CA2050953A1 - Conductivity log for boreholes - Google Patents
Conductivity log for boreholesInfo
- Publication number
- CA2050953A1 CA2050953A1 CA002050953A CA2050953A CA2050953A1 CA 2050953 A1 CA2050953 A1 CA 2050953A1 CA 002050953 A CA002050953 A CA 002050953A CA 2050953 A CA2050953 A CA 2050953A CA 2050953 A1 CA2050953 A1 CA 2050953A1
- Authority
- CA
- Canada
- Prior art keywords
- antenna
- magnetic field
- borehole
- formation
- central axis
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
- G01V3/18—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation specially adapted for well-logging
- G01V3/26—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation specially adapted for well-logging operating with magnetic or electric fields produced or modified either by the surrounding earth formation or by the detecting device
- G01V3/28—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation specially adapted for well-logging operating with magnetic or electric fields produced or modified either by the surrounding earth formation or by the detecting device using induction coils
Abstract
CONDUCTIVITY LOG FOR BOREHOLES
Inventor:
Louis H. RORDEN
Abstract A method and apparatus is described for measuring the resistivity of a formation adjacent a borehole. It relies on a modified induction approach and preferably is incorporated into a metal drill collar for MWD measurements. Directional nulls are created in a primary changing magnetic field formed in a formation by a transmitting antenna which is in a groove on the surface of the drilling collar.
Detecting antennas are placed at the directional nulls to enable the primary magnetic field to be distinguished from the secondary field caused by the current induced in the formation by such primary field. The drill collar also carries a plurality of current detectors which detect the value of current which is induced in the formation to provide a resistivity profile immediately adjacent the borehole. The preferred embodiment described uses a hybrid modified induction and electrical approach.
Inventor:
Louis H. RORDEN
Abstract A method and apparatus is described for measuring the resistivity of a formation adjacent a borehole. It relies on a modified induction approach and preferably is incorporated into a metal drill collar for MWD measurements. Directional nulls are created in a primary changing magnetic field formed in a formation by a transmitting antenna which is in a groove on the surface of the drilling collar.
Detecting antennas are placed at the directional nulls to enable the primary magnetic field to be distinguished from the secondary field caused by the current induced in the formation by such primary field. The drill collar also carries a plurality of current detectors which detect the value of current which is induced in the formation to provide a resistivity profile immediately adjacent the borehole. The preferred embodiment described uses a hybrid modified induction and electrical approach.
Description
SENT BY:BAKtR HU~H~S, ~louston; 9 5-91; 11;59 ; BAK~R HU~HES~ 91613232~44~;# 3 i O ~
CO~WCTIVITS! ~ ~OR BOR3DHO~
tor~
~oul~ ~. RORD~SN
D~aC~
~h~ praa;e~nt ln ~ntion 2~ela~ to ~ns~3r~round ~eoll~glo ~nd ~o~ u~ e~ tion~ and, nlorG
p~rticula:rly ~ to z~ mQthod and ~ r~tu~ ~or d~3terminin~ th~a resi~ativity oP z~ go~tlon ~d~o~nt ~ -looatian ln a bo~hole~
Electrical resi~tlvl~y of formation~
surroun~ing bor~ehola~ impor~ t ln ~oological studies and inv~3~tiS~tion~ ~or ~o~ u~ e4au~e dl~f~rlng matRrial~ whlch mlgh~ c¢ up ~ tc>~m~tion h~ve di~f~erent re~ Lti~, m~ur~ment o~ th~
re~i~tivity provid~a~ an lnd~ cat$on o~ th6~ ~ormatior make-up .
~h~3re now are b~io~llly two ~ rent appr~c:he~ ~or measurln~ r~ tivl~y ~Erom bor~3hol One i~ to pc)~ition a so-callqd l'eleo't~io" log tnstrum~n~ ln ~h~ J~or~hol~. ~i;uah in~trum~nt ~c~rc:~
s~Nr B~:BAKER HUGH~S, Houston ; 9- 5-~il ; 12:ûO ; BAK~R HU~H~S~ 916132328440;# 4 2 ~
curr6~nt ~om ~he bor6~holo through th~a ext~nal ~o~m~tlon ~nd me~ur~s ~h~ eo~ on liuoh o~r~nt o~
th~ m~}ca-up o~ th~3 ~orm~ti~n, by d~tea~in~ ~e~ulting volt~ge~ a~ v2~rious lo~a~lon~. ~hi~ 1:yp~ o~ log hA$1 baen ~ound ~o b~ par~ larly 0~ v~ ~or obt~inin~
ra~i~tl~rity m~a~urem~nt~ hi¢Jb~re~i~tlvlty :e4rm~ LOn6~ :rt o~t~n, thou~h, ~ uir~ nductiv~
~o~ehol~3 ~lui~ deo op~r~e. ~hi~ ~proaab h~ al~o be~n aà~tad to m~ur~wh~ d~illlng ~MWD~ tool~ lby ae~ lln~ ms~ r~ma~t al~o~rod~ on th~ me~l drlll collar no~mally p~ovld~d b~ n th~a ~o~u~l drill and tha main pa~ of tho ~rill ~m. B~u~a ~uoh ma~l drll~ oolle~r~ ~rd el~ctrically ac~n~.uc:tiv~, the ma~u~emsn~ otrod~s mu~ b~ in~ul~t~d ~rom ono ~nother to pr~vent ~ortln~. ~he in~u~tion proviAed on th~a dr~ll aollar ln tha pq~ or t~i~ purpo~e h~
been axpo~e~ And oon~aguently ~ub~ oct to o~ve~o ero~lon du~in~ tual ~rllllngt ~n~rum~nt~ ~nd o~her a~r~ngem~nts utili2inS~ th~ ~oxaQd au~nt 2 0 approa ::h are ~ rlb~ ln U . ~ . P~nt Nc~ . 2, 9 ~3, ~ o ~n~4,451,7~- G j~J~
Th~ ~ec4nd ba~ pp:Foe~sh ~ h~ b~n u~3ed has b~3~n ~r, lnduc~is:?n ~pproach. ~ne or ~no~
~ypl ::~lly ~n a~r~y) o~ ~olq~noids e2: ~ha l ike ~r2 po61t~ oned in the bor~hole to d~v~lop a primarY
Alt~rna~ing magn~tic ~ilald i~ ~che ~ ion. ~hi~
will induc~ a ciroulatlng electrlcal curr~nt within the ~oSm~tion, ~n~ ~h~ r~sultln~ ~econdary m~gn~tic ~ield is ~e~ured. 5'his ~ppro~:h 1l3 gen~rhlly ~ec~ve in low-reoi~tlvity ~o~ tlon~ o~ th~ ~yp~
llkQly to be encounterad in o~Ldim,~ant~ry b~sino which contaln p~trc~leu~" r~ervo~r~. Induc~13n l~g in~trurn~nt~ al~o h~v~ bean ~ound to woxX wh-n th~
~orshole ina}llde~ a ~igh r~si3~i~rity ~luid. ~h~
~pproaoh d~ not l~nd ~t;3~lr W~ to ~WD, ~hou~h, b~o~u~ o~ ~he nea~ 'cy o~ pro~idln~ doep SENI BY:BAKER HUGH~S, Housto~ 5-91; 12'01 ; BAKER HUûhES~ 916132328440;# 5 5 ~
~
circ:u~n~er~n~ial cut~ or çlro~v~a~ ln kh~ outer ~lam~ta~
o~ t~ drlll Goll~r to ~oid ~13ily dil~a~J$Id prot~U~ions~ In ~hi~ ~onno~tion, i~ ,~u~
rem~ e~4d that ~he ~bil~y ~f ~n ~n~ nn~ Ito gf~n~rat~
!3 A p~imAry ma~n~tio Pi~ld or ~o s~n~s I!ln induce~
~ec~ndary ~lold~ depend~ oJ~ ~he ~ n~ o~ non-~nducting oro~ otlon~l a~ t~at ~uch ~Int~nna has, ~ha r~ult~ng dæ~p ual~r4u~ in th~ out~
~i~me~e~ o~ the me~al ~ oll~ w~ak~n~
uJlac~ept~bly~ tl . S . phten~ Noo . a, ~1~, 396 ~ 3, ~33, 5~:
~nd 4,~0~73 d.i~lo~ ins~rum~nt~ u~lliæin~
induotion .
Bo~h o~ appro~ah~ ly on ~h~ ~orma~ion o~ a prlm~ry ~l~at~olna~7n~tl ~ ld which 1~ no~
di~ort~d be~us3a ~f ~r~y ~1~30~romi~gn~t~
conduo~ o~h~r than ~ho~ whi~h ml~h'c be C~u~$ed ~y th~ ~orm~tlon ko b~ m~a~ured. ~n~trum~nt~ ~nd o~h~ oonst~uc~ions utillzlng ~lt~l~r o~ t~h~
~pproach~ ho~n~lly oper~ a~ ~r~ n~ s ill ~he r~nge o~ 10 to 200 lc~z. Th~ aqu~nc~ o~ op~r~tion 1~ high ~anou~h ~o avold low~rQqu~ay noi~ bu~ low ~nough ~o neglec:t cap~cl~llre o?~r~n~ c~o~ponant~, ~lmpliPyln4 the oquationa ~:hat mu~3lt bo solvo~ to obtain a d~ r~p~ion o~ ~b~ c:tromagrl~tlo gl~ld~ ~ n '25 ~he ~ormation. ~ var~ion o~ an ;Lndu~tion in~tru~ent known ~ an "eleotromagr~tlc w~v~ r~si~tivity'l ~EW~) instrum~2nt ha6~ r3cently c:ome into ~18~. Th~ nA~e de~ives ~ro~n it~ operatlon a~ el high ~4n~u~h ~r~ n~y (A~)OUt: ~! MHZ) tha~ c~pa~tive curx~ent oannot b~
CO~WCTIVITS! ~ ~OR BOR3DHO~
tor~
~oul~ ~. RORD~SN
D~aC~
~h~ praa;e~nt ln ~ntion 2~ela~ to ~ns~3r~round ~eoll~glo ~nd ~o~ u~ e~ tion~ and, nlorG
p~rticula:rly ~ to z~ mQthod and ~ r~tu~ ~or d~3terminin~ th~a resi~ativity oP z~ go~tlon ~d~o~nt ~ -looatian ln a bo~hole~
Electrical resi~tlvl~y of formation~
surroun~ing bor~ehola~ impor~ t ln ~oological studies and inv~3~tiS~tion~ ~or ~o~ u~ e4au~e dl~f~rlng matRrial~ whlch mlgh~ c¢ up ~ tc>~m~tion h~ve di~f~erent re~ Lti~, m~ur~ment o~ th~
re~i~tivity provid~a~ an lnd~ cat$on o~ th6~ ~ormatior make-up .
~h~3re now are b~io~llly two ~ rent appr~c:he~ ~or measurln~ r~ tivl~y ~Erom bor~3hol One i~ to pc)~ition a so-callqd l'eleo't~io" log tnstrum~n~ ln ~h~ J~or~hol~. ~i;uah in~trum~nt ~c~rc:~
s~Nr B~:BAKER HUGH~S, Houston ; 9- 5-~il ; 12:ûO ; BAK~R HU~H~S~ 916132328440;# 4 2 ~
curr6~nt ~om ~he bor6~holo through th~a ext~nal ~o~m~tlon ~nd me~ur~s ~h~ eo~ on liuoh o~r~nt o~
th~ m~}ca-up o~ th~3 ~orm~ti~n, by d~tea~in~ ~e~ulting volt~ge~ a~ v2~rious lo~a~lon~. ~hi~ 1:yp~ o~ log hA$1 baen ~ound ~o b~ par~ larly 0~ v~ ~or obt~inin~
ra~i~tl~rity m~a~urem~nt~ hi¢Jb~re~i~tlvlty :e4rm~ LOn6~ :rt o~t~n, thou~h, ~ uir~ nductiv~
~o~ehol~3 ~lui~ deo op~r~e. ~hi~ ~proaab h~ al~o be~n aà~tad to m~ur~wh~ d~illlng ~MWD~ tool~ lby ae~ lln~ ms~ r~ma~t al~o~rod~ on th~ me~l drlll collar no~mally p~ovld~d b~ n th~a ~o~u~l drill and tha main pa~ of tho ~rill ~m. B~u~a ~uoh ma~l drll~ oolle~r~ ~rd el~ctrically ac~n~.uc:tiv~, the ma~u~emsn~ otrod~s mu~ b~ in~ul~t~d ~rom ono ~nother to pr~vent ~ortln~. ~he in~u~tion proviAed on th~a dr~ll aollar ln tha pq~ or t~i~ purpo~e h~
been axpo~e~ And oon~aguently ~ub~ oct to o~ve~o ero~lon du~in~ tual ~rllllngt ~n~rum~nt~ ~nd o~her a~r~ngem~nts utili2inS~ th~ ~oxaQd au~nt 2 0 approa ::h are ~ rlb~ ln U . ~ . P~nt Nc~ . 2, 9 ~3, ~ o ~n~4,451,7~- G j~J~
Th~ ~ec4nd ba~ pp:Foe~sh ~ h~ b~n u~3ed has b~3~n ~r, lnduc~is:?n ~pproach. ~ne or ~no~
~ypl ::~lly ~n a~r~y) o~ ~olq~noids e2: ~ha l ike ~r2 po61t~ oned in the bor~hole to d~v~lop a primarY
Alt~rna~ing magn~tic ~ilald i~ ~che ~ ion. ~hi~
will induc~ a ciroulatlng electrlcal curr~nt within the ~oSm~tion, ~n~ ~h~ r~sultln~ ~econdary m~gn~tic ~ield is ~e~ured. 5'his ~ppro~:h 1l3 gen~rhlly ~ec~ve in low-reoi~tlvity ~o~ tlon~ o~ th~ ~yp~
llkQly to be encounterad in o~Ldim,~ant~ry b~sino which contaln p~trc~leu~" r~ervo~r~. Induc~13n l~g in~trurn~nt~ al~o h~v~ bean ~ound to woxX wh-n th~
~orshole ina}llde~ a ~igh r~si3~i~rity ~luid. ~h~
~pproaoh d~ not l~nd ~t;3~lr W~ to ~WD, ~hou~h, b~o~u~ o~ ~he nea~ 'cy o~ pro~idln~ doep SENI BY:BAKER HUGH~S, Housto~ 5-91; 12'01 ; BAKER HUûhES~ 916132328440;# 5 5 ~
~
circ:u~n~er~n~ial cut~ or çlro~v~a~ ln kh~ outer ~lam~ta~
o~ t~ drlll Goll~r to ~oid ~13ily dil~a~J$Id prot~U~ions~ In ~hi~ ~onno~tion, i~ ,~u~
rem~ e~4d that ~he ~bil~y ~f ~n ~n~ nn~ Ito gf~n~rat~
!3 A p~imAry ma~n~tio Pi~ld or ~o s~n~s I!ln induce~
~ec~ndary ~lold~ depend~ oJ~ ~he ~ n~ o~ non-~nducting oro~ otlon~l a~ t~at ~uch ~Int~nna has, ~ha r~ult~ng dæ~p ual~r4u~ in th~ out~
~i~me~e~ o~ the me~al ~ oll~ w~ak~n~
uJlac~ept~bly~ tl . S . phten~ Noo . a, ~1~, 396 ~ 3, ~33, 5~:
~nd 4,~0~73 d.i~lo~ ins~rum~nt~ u~lliæin~
induotion .
Bo~h o~ appro~ah~ ly on ~h~ ~orma~ion o~ a prlm~ry ~l~at~olna~7n~tl ~ ld which 1~ no~
di~ort~d be~us3a ~f ~r~y ~1~30~romi~gn~t~
conduo~ o~h~r than ~ho~ whi~h ml~h'c be C~u~$ed ~y th~ ~orm~tlon ko b~ m~a~ured. ~n~trum~nt~ ~nd o~h~ oonst~uc~ions utillzlng ~lt~l~r o~ t~h~
~pproach~ ho~n~lly oper~ a~ ~r~ n~ s ill ~he r~nge o~ 10 to 200 lc~z. Th~ aqu~nc~ o~ op~r~tion 1~ high ~anou~h ~o avold low~rQqu~ay noi~ bu~ low ~nough ~o neglec:t cap~cl~llre o?~r~n~ c~o~ponant~, ~lmpliPyln4 the oquationa ~:hat mu~3lt bo solvo~ to obtain a d~ r~p~ion o~ ~b~ c:tromagrl~tlo gl~ld~ ~ n '25 ~he ~ormation. ~ var~ion o~ an ;Lndu~tion in~tru~ent known ~ an "eleotromagr~tlc w~v~ r~si~tivity'l ~EW~) instrum~2nt ha6~ r3cently c:ome into ~18~. Th~ nA~e de~ives ~ro~n it~ operatlon a~ el high ~4n~u~h ~r~ n~y (A~)OUt: ~! MHZ) tha~ c~pa~tive curx~ent oannot b~
3 o negl~ted t ~nd ~h~ equatlon~ do~r~blng th~
~urrounding ~eld~ and th~ propa~z~ting w~ nod~
mu~t b~ ~on~3~d~red. AltAoug~ ~e ~eom~'try in~truma~ g~ne~ally æimil~r ~o that o~
c:onven~ional lnd~lctlon in~rumQnt~, ~he o~allow~
unde~ut p&rmit~e~ by it~ high~ s;tuen~:y oper~ion ha~ r~33u~ d ~n i~ u~e wlt~ s~ndard ~WD ~oll~r~. .
SENT B~':BAKER HUGHES, Houston, 9- 5-91; 12:02; 3AK~R HUGHES~ 916132328440;# 6 4 ~
Howqv~:, th~ ~ttenu~ion or WelV1~8 ~rav~lllng in a conductirlg fo~ tion inara~ wlth Pr~ 4n~y. ~he re~;ul~ ~a6~ be63n EW~ ~rran~R~nt~ provld~ ~ow~ d~th o~ inY~ lg~tlon in low ~oi~t~vitl~a ~h~n ty~lo~lly arQ of ir~t6!~e~. A~ ~n ~xample o~ att~u~tlon, at e~ r~ ity o~ ~ 2 ob~-~o~rED ~ho a~ n~ on ;l~
grQ~t~r ~han on~ de~b~ p~3~ lnc~ ~ trav~ n 'ehis ~or~nec:tion, it ~l~o mu~l; b~ r~m~ e~ ~h~k ~luglrlg ur~ment it 1~ necse~$~ry ~h~t ~hs p~ sr y ele~tromagn~tic: risld w~i~h 1~ inducad ~r~ hr~u~h fluid (~yp~ ::ally csAlled a drillln~ "~ud") ~hi~h is circuln~d ~h~ou~ e ~ hol~, ~rhe p~ n~ ;Invcllntion r~la~ to ~ method and app~2~Atu~ c:orpo~ m4dl~1ed lnduc~lon ~ppro~c:h~ whiCh not only a~n b~ u~d wlth ~n rom~n~lc:Ally c:onduc~iv~ ~a~rl~l ~u~h A~ tln Mwr) d2~ill coll r, ~ut t~k~ adv~n~ag~ o~ lts F~ndu~tivl~y . In ~undunen~æl ~mB, a ~na~ o~ ~p~ot Qi~ t~e ~nv~3n~ion i8 direota~ to ta~e~ng ndv~nt~ o~
tho null locu~ o~ a ~ompon~n~ Or a p~lm~r~f Ghanq~ng magnetic ~leld ~orm~d ln ~ ~ormzltion, and plaalng detecting an~3nne~; a~ ~p~ po~aition3 ~ c~
relativ~ ~o l:h~ nu~l Qna~llng th~ pxl~ary ~gn~tlc ~lel~ to l~o ~ inguioh~ rrom ~he ~a¢on~ry ~i~ld cau~c~ by th~ ourrsnt ind~ed in th~ ~o~m~tion by ~he primary ~iald. Mo~t ~ irA~ly~ ~A~h o~ th~ det~ting ~ntenn~s i~ po~ onl3d rlg~t ~t~ a null 30 as to b~
directly de~oupl~ad i':rom th~ pr~mAry ~i~lcl p~ttern, alimina~ing the n~ce~sity oP c:~ncq~lin~ th~3 p~iIQ~ry ~ial~!l by ~ uo~clngl~ corm~oti~ o~ r~ vln~
ant~nn~3.
T~ tr~n~mi~tlng ant~nr~ ) and ~h~3 d~a~tin~
antenna(~ not po~ n~d circum~rontiA~ly Abc~ut SEN, B~`~AKER ~UGHES, Houston ~ 9- 5-91 ; 12:02 ; ~A~ER HUGH~S' 91613232B440;~ 7 .~ , th~ oll~r. Rakh~, th~y ~ AC:~d ~n corr~sponding groo~s or ~ llk~ h~3 clrill oollar~s escte~ior 3uraV~ hi~ ~nn~otlon, th~
an~nna~ ~n b~ gonarAlly ~lon~t~d an~ bly ~nolude a magn~tlc: ~or~ A~ b~ough~: ou~ ~bov~, ~n t~ p~t 1~ ha~ b~3n n6l~a~ o p2-ovlde rol~tl~fsly dll~lap out5 or groo~v~ ln ~l~o out~r c~a~D~at~r o~ a drlll ~oll~ to, amc,ng o~ r ~cblng~, provido ~&ho non-~olldu~ting cro~ o~tional ~ or ~ho ~nt~nn~ ~:ha~
10 i~ r~uir~ in~tan~ ~mr~n~ion ~llow~ th~
ln~lu~ion o~ ~ magnRtia c~ore ~:o c:ono~ntr~to th~ ~lux, th~re~y re~du~lng ~h0 cros~ c~lonal ~r~A th~t 1 n~ed ~
A~ ~no~h~r ~t3atur~a o~ tha lnv~nt~on, ~ho 15 ~uppo:rt ~u~ture rox ~h~ ~n~nne~ 4trloally ~on~uct~v~ arld ~axrie~ A plu~ali~y o~ sur~nt d~ec~ors bu~ in in~u~ d ral~ion~hip ~h~r~o.
EA~h o~ ~h~ de~ooto~a i8 po~ on~d to fl~c~ ~he VAllUe O:e ourrenl: b~ing x~03iv~1 by th~ ~m~ from ~e ~0 forma~ion~ In thi~ c:onnac~ h~ ~t~c~ors Ar~
po~1~ion~d ~ ring r~di~l pwltion~ ~el~iYo to tne axi~ ~ th~ ~upport struci:uXe, wh~ar~y ~s~b ~a~ct~s A ~i:e~r~n~ valu~ o~ oux~n~C. TheAe cu~r~nts wlll reE;peotively ~low through $ucoe~ roly d~ap~ar 25 lay~rs o~ the Pormatio~. This set ~P ~a6~ men~
then produc:e~ ~n ~e~ima~e of the radi~l r~ tivity pro~lle o~ ~he ~ormal;~on immediAtaly ~d~ ~a~n~ th3 ~orohol~ .
It will b~3 reco~n~z~3~ thAt ~h~ abovqs ~u3:r~n~
3 0 m~a~ur~ng ~ahniqu~ h~ re~ult o~ u~ing a ~h~gnq!tlc ~i~ld sc~urc~ t:hat iCI not axi~lly sy~T~otrio, i. ~., tha$ i~a o~ xlo ~ela~iv~ ~o th~ bor~ol-l ~xl~. ~rh~
o~-axl~ ri31~10n~ip ~ orlo ~r ~or~ o~ th~ ~n~rmaa may ~l~o Allow d~exmlnation o~ b~d~in~ pl~no d~p and ~he dlret~ n s:~ a b~àdtng pl~n~.
SENT B~:BAKER HUGHES~ Houaton ; 9- 5-91 ; 1~:03 ; BAKER HUGHES' 91613232a440;~ ~
~ ano~her ~at:ur~ h~ ln~ ion, la~ a pl~rall~ o~ d,e~ec~t~ n~enn~ ~r p~ovld~ 2t n-amine~l dir~ i~af~h~ ~ pxovld~d by e~oh ~11 havfa ~/i3rta~n c:om~o~ o~a;~aJt~ tlc:oO Blnco 30~, ~hi~ ~ommon mod~ a ~ ot ~ pon~o to ~h~ ual p~i~ary ~iel~, lt ~oe~ not helv~ to ~ oomp~n~atsd ~or ~h~ fir~t-order ~ ct~ ~ mud r~ ti~lty, oDl~Lr ~smp~a~:ure, ~rivo ~mpl ituda, e~ n~ are pr~ide~ ~o ~n; ~ th?3 ne$~ v~lra o~ in-phe~
0 ~n~ r~ture c:o~o~s ~od~2 in~ the~ m~in sl~n~l ~hAn~l to ~omp~n~e ~or tll~ ~ac:ond-ord~ ull rs~idu~
'rha primary ma~net;io ri~ld, ~a~in~d ~ th~t ~ 1d wh~c~ ~xi~ in the ~bsen4e c~ arly aon~u~ting ~oxmatlon o~ bo~hole ~lul~ o~mpo~ ld mad~ up not only o~ th~ o~ ed ~y ~h~
tr~ mittlng ar~enna, but ~130 by ~ d ~at~d J~y th~ c~ric~l our~ent induc:~d tr~ ~h6~ ~onduc:tiv~3 ~rlll col~a~ l.
Th~ prim~ry ~iQld p~ttern o~ b~ aynth~i3ed by gi~ sev~al tr~omltl;ln~ ~nt~nn~
eimul~;aneou~ly~ ~hi6 mod~ h~ null lo~l and, hence, th~ pi~c~em2n~ o~ ~ho datocti~g ant~lnna ~o~ .
Moreo~ror, plural null locl oan ~o roxm~d to permlt more ox~noi~re ~i3trlbution o~ ~etQ~éln~ ~n~nn~s.
It i~ al~o pos~ibl~ to pl~oe! aàditionAl dat~oting ant~nnaa in po~i~10n~ ~h~ ~r~ no~ ~alec:~d ba~ad o~
the null loc::i, U~in~7 ~p~ropriRt~ w~algh~ln51 Or Inultip~ lqmen~s ~c aohi~vl~ c:anc~llat~on a~ ln corlv~ntlon~l 10~6.
W~ th ~fe~enc~ to th~ ompanyin~ th~ e~t~
~f drawlng~:
SENT UY:BA5~ER HUGHES, Houston; ~- 5-91 ; 12'~4 . BAK~R HUGHES~ 91613232844~;# 9 .
~ O ~ ~
t'~
~.
. . -7 ~IG. 1 i8 a ~hem~tlo, broken ~ q~ elevs~on i $ ~ 3`~ - b~ T'I;~r~ 3 ,. , , . ~~;: , .1~;?1 /t~q ~ t~q~ r~ r~i~? ~
, . . i, :- : , ,' "`,. ,' ~ .i.?.. ~ 3 ? ~ q~ r~ ; Si ?~
,' ' ~ . ' ;'/ ~ ~'' ' , , ` ' ~' .. ' " .;~ '`
. ~ . .
SEN~ ~Y:BAKER HUGHES, Houston; 9- 5-91; 12:05; BAKER HUGHES~ 916132328440;#1~
a;
FIG. ~ , A seC~ oJl~l viaw ~imil~,:r t:~ FI~. 1 taken on a plane in~i~at~d by ~e ~in~ llA~A in ~I~. 10;
FI~ Ano~hor ~ct~on~,l vi~w ~Aken ~n a plan~ indi~ d ~y th,~ lln~ in ;~ . 10 7 Bn~
FIG, 1~ oh~,mAtl~ bl~ok di~g~m ~rl@~ o~ a p~er~d r~oe:l~ing ~h~nn~l o~ ~he ~n~ ntt~n.
~IGS . 1 ~nd ~, illu41trat~ the ~undAmantA~`
lo prin~ipl~ o~ ~h~ stAnt ln~r~n~l~n, ~nd ~. 3 inalud,e~ r ~ b~ a~ us~der~t~nding o~ th~ ~am3.
Wlth r~r~n~e ~o ~I~S. 1 ~r~d ~, ~ w~o~na~ia r~pr~en~At~On 11 o~ ~ metal ~rill c:oll~
~llu~t~at~d, As t~ known, ~U~h ~ dr~ oll~r i~
~5 located b~tw~en th~ drillln~ ~t~ or pip~ ~nd th~
drlll~ng bi~ during th~ forma~ion ~ ~ boreh~
r 11 includ~ a ~ln ~xl~ 1~ which when tho ~tru~tur~ 1E; wi~hin a borehole i~ ~ean'c to b~
gen~rally aoinc:ldent with th~ boxehol~ ~en~r~l ~xl~, 2 o :L . o ., ~ llne ~r~wn centr~lly through ~h~ b~eh~le hlQng its l~nyth. c:011Ar 11 1~ ~ypioal in th~ ik 1 metal, u~d ~or drill ~ o imp~t w~lght and 3~r~ng~h .
MWD (Me~ rç-Wh~ D~ ng) 1~ a~c~mpli~h~d by 2 ~ in~trumentation whlah i~ a~ooiat~ wlth tho ~tAl drlll ~ollar. ~8 ~nention~d abov~, the tw4 ~ppro~ah~
whioh h~v~ been U8B~ he pas~ to m@asu~ the re~i~tivity o~ ~ :eorm~tion aurroun~lng th~ borehole h~vo no~ b~en ad~ptod ~a~ torlly to MWD
3 o op~ratlon . ~n~ ~ea~n fo~ ~hi~ ia ~hAt, b~aau~ h~
dr~lling ¢oll~r typic~lly 1~ el~Gtrlcslly conduat~vs, induotior~ type ~pproa¢h~ hav~ ~e~ r~lativ~ly SENT BY:BAKER HUGHES, Houston , 9- 5-91 ; 12:~5 ; BAKER HU~HES~ 91B13232~44~;#11 , g de~p circ:um~er~n~ial yr~ov~ t~ ~e ~ortned ~n th~ dril 1 oollar to hc~u~e th~ ~n~e~n~(s).
~he pr~on~ invantion ~ak~ d~nta~o o~ 'eh~
~l~ctric:~lly ~nnduotiVe natura o~ ~h6~ Ll asll~r.
I~ has been ~ound ~llat i.~ ~he ~r~ mit~in~ ~ntonn~
i~ po~ltlon2tl o~ xl~ o~ th~ m~in ~XiB 0~ th~
~ol ~ a~ ., radi~lly o~ om the b~hol~
c6!n~r~ axi~ a ¢h~ngln~ prlmary ~ n~ ield iE~
îonn0~ w~ioh ~aa3 loa~1 o~ ~x~ oo~nponont mlni~a on lo th~ ooll~r l3ur~ , That ie, a "prlmary" 3i~as~n~tic f isld 1~ f~ 3d whioh hfl~ ~ lo~t~on ~t whi~h th~
diraati~n o~ th~a ~xia~ ~ompon~n~ o~ ~h~ ld nomin~lly ~ n-ph~e~ wi~h ~h~ allt~nn ~l~ld wil~
~ve~ h~ loou~ o~ tbi~ x~Ye~al 1~ r~er~d t~
1~ herein ~8 a "dlr~a~ional null . " ~inae the ~gn~tio gi~ld o~ ~h~ tran0mlt~1n~ ~nt~nraa indllaa~ a cur~enk in tho metal ooll~r lt7~ th~ prlm~ry m~gne~i~
~i~ld a~ u~e~ }~ex~in ~ a~tu~ a c:omposlte ~l~ld m~d~ up by the ~up~rpo~ition o~ sna~n~o ~i~ld 2 0 c~a~e~ by tha tr~n~mittlng ~n~nnA dl;E ~ctly, an~l the ~Gondary ~ reated by th~ qur~ whloh i~
induoed ln th~ condu~lng ~oll~r~
Mo~t ~sirably, ~ r~ns~ lng antennA ~ 18 loo~od on or n~3Ax a ~u~ e o~ th~ drlll 4011ar by, f~r ~x~mplo, ~lng plaosd wi~hln ~ groov~ A5 lllustr~ted, A~ ~3hown ln FI~. 3, auch ~r~n~mitt~ng an~enn~ ~ylln~rio~l or / /~
rod ~hap df~(elaat m~ ~or~ 14 wh ~h iB 4pir~11y ~/V r, wr~pped wlth c~ndu~iv~ wire 15. ~hlo ~ono~ruc~t~n wlll reBult ~n optl3~um ~lux tr~nsr~ls~ion ~lno~ Plux ~ ~7G
ln ~h~ ~nt~nn~ i~681~ ~o~m~d by csurrent ~lowlrlg 6 throu~h the w~ re lS wlll b* c~onc~antr~t~d by th~ ro~
1~ .
SENT BY:~AKER HUGHES, Houston ; 9- 5-91 , 12:06 , BAKER HUGHES~ 9161323Z~440;#12 ~ has been ~ound that a d~rRc~ional mlll r~p~ ted at 16 will b~ ~oxm~ on l:h~ ~}r~e o~
the drill ~ollar ~lr~um~e~ntiall~ ~bout th~ ~am~.
~n k~eplng w~th ~h~ lhv~ntiorl, th~ d~t~otin~ Qntenna ~or det~ct~ng th~ ~ield produ~ed by l:he c:ur~ent lndu~d ln th~ ~orm~tion i~ poQ~loned ~t a lo~a~lon relativ~ ~o ~uoh null ~t whir~h ~uoh ~ond3.ry magn~tit~ ld 1~; di~tingul~hable ~om ~he p~ na~y magnetlc~ ld. Morsov~r, ~ox m~Xim~m t!l~pth o~E
1~ ln~.rs~tiga~ion ~rhen a ~lngl~ de~:~c~ing ~ntennA i~
u~ed, ~ t i~ p~Pe~A~le tha~ lt b~ di~m~ a~lY
oppoai~e ~h6~ ~ransmi~ting Qnterln~. Antonn~ 17 i~
~uc~h a d~t~ g ~nt~nna. ~t~ ~on~ltrua1:~.on 1~
~imlla~ ~o that o~ the tr~n~mit~ing ~n~nn~ 13. Mo~t d~sl~a)~ly ~ t i~ deooupled ~r~ h~ pri~nary m~g~e~
~iald by beln~ po~ icnad rlght ~ null~ muE;~
b~ r~m~m~o~ ough, that: ~u~b ~.ek~ln~ ~nt~nn~
h~ a ~lnit~ l~n~th, nn~l wh~n th~r~ ou~olon ln thl~ ~oo~m~nt a~Du~ po~i~ioninsa ~e ~ lny Oy~O~n 2~ ~t th~ null tk io ~eanl: po~ ion$nçl th~ d~t~ting an~nni ~or nominal z4ro ou~5~ut.
Although ~ per~e~t ~root~on~l null ~heor~ti~ally wlll o~.cur, tl~ with ~h~ u~nptior that th~ colla~ iB a pGr~s~t: oonduotar. ~hQ
pr~ct~l Oel92 C)~ ~inlte c~nduotl~rl4~ r~u~t~ in ~
~rQry do~p mlnimum, bu~ with ~ome r~dual qu~d~Atuse oomponon~ whiah mu~t be com~ç~n~ato~ ~or to as~ure p~oper opex atl~n .
~i~ld lln~ 18 ~ra ~uperimpo3ed an th~ drswlng 3 o ln FIC . 1 to ~how ~he natur~ o~ ~h~ ~rimary ~Dagnetic fi~ld. ~hi~ ld i~ a ~omposi~ o~ tho ~-ld cFe~ted ou~side t~lo collar by th~ kr~n0mittlng ~ntenn~/ an~ a pro~ction on tne ~lane og ~uch Xleld, o~ tA~ ~econdary fleld cau~ed by Guxr~nt induoe~ ~n th~ con~uotill~ ool1a~D A~ ~hown, ~ iald ~t th~
SE~T BY:~AKER HUGHES, Houston; Y- 5-91; 12:37; E~AKER HU~ES~ 9161~232~440;#13 205~vn~3 ~aUX'~AC:e and Oultgia~ tha c~ollar iri ~h~ ~rD.n~vorse b~ tlng plane o~ ~h0 ~r~n8mitti.ng ant~nr~ 13 i~
ev~ywh~e axial an~ dlr~ot~ oppQ~1t~ly ~o th~ ld ln the ~ntenna oo~ will be ~ec:ognlz~d that th~
dixa~tlonal hu~l 10~UQ in ~a~ lr~um~ ib~ tha m~tal c:ollax. Mor~ov~, ther~ will be two null lo~li th~t e~Q ~m~d ~bou~ a plan~ bi~ ing tho tran~mlttlng antenn~, Ax~slly ~y~Nne~r~O o~ ~h~ 0411~r 11 r~lAtiv~ ~o the ooll~r m~ln axl~ la o ~l~ul~n~ou~
10~s~tl~ m~u~m~ h~ r6! ~n ~ w~
axiAl ~para~lon. Thase oou' ~ be u~d ~ r~y elem~n~ ts ~ynthe~z~ dl~eront in~e3ti~tlon p~ttornR, or on ~ rota~ng ~oll~ to ~oi~
d~t~mlning 2~ppsr~nt b~d~ing pl~ne dip.
15F~G. 4 i4 ir~cludqd ~o ~llitA~ ~n und~rQ~ndln~ be in~t~n~ lmr~n~lon. I~
lllu~tr~t~s ~he fl~ld ~o~ by a eonv~nl:ional wl~
1 ln~ lo6~ arranyam~nt ~ Suoh ?~,xrang~men~ l ncJl ud ~tran~ ter c:oil 21 whlch i8 ~ dded ln a non~
~l~c~ricAlly aonducting, ~loslgat~d body 22~ ~lnco ~uch l~od~ 1~ non-condu ::ti~re, ~h~ magn0tia ~lux pAtte~n o~ ~h~ primar~ ld form~d by the ~ra~mitt~r ~oll 21 will not be "~ls~or~qd" ~y the flxio~tanc~ o~ ~uch body . Although ~or ~i~pl io ~ ty the ~5 ~lux p~t~rn i~ ~nly ~hvwn in ~wo dlm~n~ions, it will b~ r~co~nl~d ~hn'c ~here i.B 11 th2~0~-dlm~n~lonal ~lux patt~n which i~ ~imply ~n Axl21~ rla ~igure O:e r~volution o~ that ~howr~, ~ co~vent1onal Arr~ngoment as P,hown in FI~. 4 3 o typio~lly 1nalude~ two ~epar~t~ r~o~lver coil~ .
~e6e ~o11~, repr~en~d a~ 23 an~ ~4, ~ po~tioll~d on th~ body ~o that ~he ~urr~nt in~uc~d ~n the ~am~
wlll ~o in ph~E3e. Th~ ~mplitu~o~ o~ t~ ou~ont oallsed by the pr$m~ry mAgn~io ~ld will 1:~
appr~xlmat~ly inve~se to ~h~ ~ube o~ t,hoi~ ra~p~otiYe SENT BY:BAK~R HU~HES, Houston, 9- 5-91, 12:~8, ~AKER HUGHES~ 91613232844~;#14 2 ~ 3 dl~tanc~ ro~n the trah~mi~i;ing ~:oil ;~1. To ellmln~ primary ~i~ld biaEI o~ k~le ~og outpul:, I;hb ect c~upl~ny ~ 4h~ p~imary ~ ld io c~nc:el~ ou~
l~y ~ g ~h~ appropria~oly w~i~h~od t3~ oo~ ~
IBign~ll8 induc~d in ~he~ two noil~ . ~n ~l:hær word~, lt ~ nac:¢2~ary ~o h~rs two r~celvin~ ¢oll~ to enahl~
elimtna~lon o~ prim~y ~leld b~Ae. q!wo r~aivlhg cc~ils ~re no~ nec:es~ry ~02~ the in~t~nt lnvontlon, ~lth~ugh, 1~ d~lr~d, ~nultipl~ Clet~¢ting (o~
~an~rqitt~ngJ ~n~nna~ ~ay be u~ o ~yn~h~s~n di~or0n~ depth~e~olu~ion ~ t~3~n~, ~o~ove~, ~h~
~ah~me ~ h~3 ln~ta~ lnvontion enabl~3s on~ to p~.AC~
~h~ ~et~a~lng and ~an$m~tt~ng ~s~n~enna~ ~u~h olo~or ~ ~n~ Ano~h~r an~ t~es muoh 1Q~Et POWeX th~n 1~ conven~lonQl a~ran~ment~
F~Gs, 5 and 6 illustr~te a ~lmple ~r~Ay u~lng ~wo t~An~ tlng a~tonnhs ï3~ wh~oh ar-a dl~Jnetri~
oppo~d to one ~no~her and ~wo ?~ceivlng ant~nn~ 17 w~ioh ~ alEso diamots~tcally oppog2d to on~ Anothor~
2o but ln a plano pe2~pendi~ular ~o ~h~a p~an~ o~ th~
tran~mltting antOnn~B- Th~ Islmples~ ~lectrii::al ¢on~lgur~ on ~o~ thl~ arr~y 1EI on~ in whic:h a~oh antenn~ pair i9 oonn~q~ed oithe~r in par~ l o~ in 3erl~, r~ ltlng ln ~ oin~l~a tran~sm~ttln~J ohannol an;l a olngle reGei~r~ng cn~nn~ hl~ g~m~t~y i~
0ensiti~e to ~ircum~ren~i~l inhomog~n~iti~s of ~orm~tion r~ stivity ~h~n th~ un~ rlc:~l configuratlon illuetr~t~d in F~G~3. 1 and 2 .
Mor~over, it has #omewh~t bQtter ~hln-l:ed r~solution.
~y the ~lmplo expodlont o~ fl~teot~ng th~ 3~gn~13 fro~n the two r~c:eiving ant~nna~ ~e~arat~ly and cclrrolating Wit~l rotation durlng rotAry drllling by, ~or ~x~mpla, u~ing dat~ rrOm ~ixeot~onal ~en~o~s lncorpor~od 1 thQ tool, ~6ddin~ pl~ne dip ~nd ~ik~ ~an be 3 5 resolved .
. . .
SENT ~Y:~AKER HU~HES, Houston, 9- 5-91; 12:~9, BAKER HU~HES~ ~161~232~40,#15 The ue~ Q~ a tran~mi~tirJ~ ant~nna ~h~t i~ not ~xiAlly ~y~nm~tric provi~ a di~e~anlt ~pp:roAah to r~ vl~y mea~ure~ment. FI~. 7 ~ olud~l t~
~cili~te D.n und~3rotandlng ~ thi ~ appro~c:h ~
d~piotoe lin~g ~epresontln~ th~ el~a'cr~.~al ~leld ndu~ed by ~he primary mag~tla ~i~ld t2~ ~he ~ioinity ~ tho o~n~r~.l plan~ of a t~ansmi~;ln~ ~nt~nn~ 13 in ~ dr~ ollar r~p~e~antæ~ in eros~-~eetlon. .
Th~e ~lectria ~eld lines sre ~uperi~po6ed on l:hQ
~adl~l re~ r~ty z~na~ that ~asl ~ di:~erentiate~
ent a d~;llling ::oll;~r ln a bo~eh~ xosp~ ~or di~tor~ion~ ~n~roduced by boundary ::onditl~n~ b~tw~bn ~on~ ondu~on ou~ront~ w~ ll k~nd to follow ~h~e ~l~ct~ioal ~iel~ . A~ illu~tr~t~3~, all c)~ the hybrid aurrer~ pa~h~ aro ln~er~ept~ y ~he aoll2l~ at a normal in~id~nce r~sluixæ~l by ~t~ h~gh o~nducl:lv~ty~
~hi~ ~omplet~ th~ c:los~d ~:~ndua~lon p2lth~ . In k~epin~ wi~h ~ inventlon, ~n ~rr~y o;~ el~trQd~ 31 arQ pooitlon~d ~o tnte:rc~pt th~s~ cu~ren~, oach o~
o whi~h will ~low through a ~uc: ~a~ ely de~p~r laye~
of the ~ox~nati~n. I~h~ B ~rray i~ b~t ~ JB1:r~t~ in ~IGB. 8 ~nd 9. I~ will b~ ap~ro~a~ that ~o~ o th~0~ elec~ro~eE~ in~ul~tad rrom the ;:~lla~ ' ~u~a~ ~ut i~ ~nalntaino~ at ~h~ ~oll~r pot~ntlA~
~et o~ m~sur~ments o~ ~rolt~eo x~ ul~ing ~roYu those cllr2~nt~ will produc~ 2In ~stl~te of kho radial re~lotlvity p~o~lle t~ ~ ~apth or oeVera~ G~ r radii lnto tho ~orma~io~. It ehould be noted tha~ ~
althou~h the Array o~ ~lo~ro~ ar~ aho~7n in 3 o partlc~ular po8itlon~ on ~h~3 ~ollur ~u~ce ro}~lva ~o ~ho trAnsm~ ing an~nna, other poa~ion0 on ~uoh 8Url~2!1C:4 ~Dr ths ols30trodeo could b~ cted, dopenAlng upon ~h~ rrent i~ i3 t~ c31 tC~ -int-r~ept .
3 5 ~t~tg~ thAt ~h~ hybrld ~urren~ paths illu~tra~d ln I~G. 7 are radi~lly well c:olliJn~sd ~nd a~n .
SEN~ BY:BAK~R HUGHES, Houston , 9- 5-91 12:09 ; BAKER HUGHES~ 91~13232~44~;~16 2 ~
~4-thqr~ ro provi~ ~xa~ nt b~3d~ing-pl~ne ~olutionO
tn ~pl~a of pr~iding r~ iv~ly oh2l110W
inva~tlgA~on, ~hi~ mea~u~m~n~ ~ uo~u~ ~or llthogr~p~y while lnv~lDn 1~ ~till ~allow. Al~o, th~ hybri~ pro~ilo i~ U8e~l~Ul ~or bo~ohol~luid ~o~rectlon~ of ~h~ ~4~p~r ~n~re3:~iç7atlon pro~d~d ~y th~ lnc!~uc~orl mod~ o~ ~he B~m~ c:on~igu~;~tl~n.
~oreo~rer, i~s radial re~olution should ald ~tlm~tlon o~ ~oxma~ion p~ ility hy t~aoing th~ p~o~o~ O:e in~ra~un~ par~ioularly whan ~ pre~ 3usly-drill~
in~er~ lo~g~d b~k du~in~T tri~ping.
~I~S~ 10 through 11~ sllow ~ pre~r~d a~r~ng~ nt ~olnh~ nin~ b~th the D~gn~ n~ng and ourr~n~ ~en~ g ~spe~t3 o~ ~be lnv~nt~on~ A
tran6mittirlg xrl~nna l~ ~ep~e~ent~d ~ 13 " ' .
plurali~ oX d~tecting a~t~nn~ ~7 ~ ' ~r~ po~itlonRd cir~um~er~n~lally about ~h~ drill coll~ ~t ~As ~wo oi~auD~ 2ren~ial di2q~etioh~1 null~ ~orm~a on op~o~lte ~lde~ o~ th~ tran~mlttlng ~nt~nn~. ~or~ov~r, a plur~lity o~ ~e~o~tors 31~ Are po~ltl~ne~ ~o ~et~4t ~urr~n~.
The unlque g~o~netri~o 1)~ th~ inv~sntion pormit the ~10e of magne~io ex~itation wi~h c:urrent ~ensing 'ch~t ~eln ~ oonstxucted to h~ ry hl~h 2~vlutio~
both radially anfl ax:L~lly. Although limi~ed ~o ~latively ~hal~ow inv~tl~e~tlon, 1~ can be U~ to resolve lnva~lon pro~lleo, co~ ens4~Q ~or borol~ol~
~ect~, ~nd resol~re thin bed~ in fl ~re~hly-drilled hol e. Th~ ao~bin~tlon o~ magnetic~ n31n~ ~Y;Lth 3 ~ ~ ndu~d c:urren~ sen~ing ~esults ln ~n arrangem~nt which p~ovl~es both ~hallow ~nd d.~ep ln~o~tig~iorls.
Anothar ~ature o~ th~ in~ n~ insrentlon is th~
pre~ncQ o~ a common-~ode ~ignal ~2-om ~aoh ræoo~ring ~ntenn~ ~h~t o~n ~e u~ed kc~ ~u~pr~ h~ re~ldual SEN~ ~Y:~AKER ~U~ES, ~ouston, 9- 5-91; 12.10; ~AKER HUG~ES-~ gl~l3232~44~;~17 2 ~ 3 primary-pi~d respon~ ~o ~ho nomin~l dlreqtlon~l null. slno~ thi~ o~mmon mo~ diroot ~e~pon&e ~o the ~tual p~lm~ry ~i~ld, aom~na~tâon ~o~ not hav~
to ~a mAde ~or ~ho ~ t-Qxdor o~n~ o~ m~ld ro~i#tivi~y, collar t~mp~ra~u~e,. ~rive ~mpll~ude, ~t~. In~tead, ~ ml~rop200a~0r c~n~roll~r can b~
provlded ~o ~n~ ~o~ th~ n~a~ y lev~l~ oi~ ln-Rh~e An~ tauadr~tura common-mode ~nt~ th~ ~aln ~gnal c:hannel ~o c:l~mps~nsA~e ~or ~h~ ~oaon~ and hiSlhor o~dor null ~e~iduals, ~ollowing 2i ~ao~al oon~t~ t~ rom t:QBt me~sur~men~ Xn othor wc~ ho d~t~c)ting ~ntann~ ~n ha~re a ~c~ntro;l.l~x ~or addin~ eon~kant char~c~ri~ s o~ a E~ign~l ~o ~h~ cu~en~ lndu~ed :ln th~ ~am~, to ~o~peno~te ~or ~ign~l o~ara~t~rl~
1~ ~aus~d by t~ rim~ry m~n~ iol~.
~G. 12 s~hom3~ioally ~llu~rat~o ~uch ~aoelv~r channel, ~h~ ~urrent indu~d ~y the pr~m~
f ~ el~ ~aa6 a 81gnA1 value over th~ len~th o~ tb~
re~lv~n~ ank~r,n~ ts) . ~ow~var, in ~ho pr~rr~d ~o &rr~ngQm~ hq roceivin~ ~ntannat~ ~pan{E~) ~
~ire~on~l null. ~uoh an ant~nna, r~r~ent~ t ~1, ie aoupl~ to a ~z~in ~l~nal p~eampll~l~r g2 through ~ ~ran~f c~ r 4 3 with ~ c:ant~ pp~ p~im~ry windinq. ~ince th~ ~ur~b~t lnduc~d by tho prima~y ~lold r~v~r~e~ po~rity n~ar ~ nt~nna con~ , the Comm~ mode ~rolt~ge be~w~n the ~ntennn eLnd trane~ormer C~e~tQr ~ap~ Will be proport:l onAl to ths ~u~n o~ gnltud~ o~ th~ r~pon~e o~ ~-h~ ~n~nna halves to the priTnary fia'~ d. ~hea~e wlll ~ oan~ele~
3 0 ~o khe ~lrst ord~ar. At the ~ame tlm~ h~ ~ec:ondax y sign~l~ o~ in~ereet will be in ph~s2 otrer th~ l~n~h the ~ntenna, cr~tlny a dl~tr3n~i~1 8i~nal that lve~d to lthe sl~n~l pr~ampl~ r 4 conunon-~node pr~ampli~ 44 i~ connec~ed ~we~n th~
oant~r ~p~ o~ ~h~ dato~ttn5~ ant~na a~ illu~tr~tsd.
It ampl~fies l:ha prl~nary ~ield r3plioa1 wi~h thæ
SENT By:BAKER HuaHEsl ~ou~ton; g- 5-91: 12~AKER ~U~HES~ ~1613232~44~
2 ~
~16;
la~oollda~y rs3pon~e s: ~noel~hl~ p~ mp~ r dr~v~ ~ pais~ o~ m~ opr~or-~on'croll~
Att~nU~ 4~ ndl 47 ~th~r~p~ooae~r l~
r~p~ n~ld ll~ 4~ lllu~at~ rullto~ ~7 ~v~n b~ ~:ho pre~mpllP~o~ 4~1 ~hrou~ ph~
ng ~a~2t~ork r~pr~ od çlt ~ g~nua~or~
4B æ.nCI 47 l~pl~men~ ~h~ mc~dRll~ oond order p~im~ry ~1 ald ~irelction~l nulls prov~ by the microprc~ s30r oontro'~ he ~ig~ sre ~umm~d with th~ output ~ror~ ~he m~in ~lgnal pr~ampli~ie~ a~
i~ xepre~ente~ ~ 51 ~nd 52. ~ outp~lt ~n~
th~ d~lr~d d~teation ~ ~gn~1 wi~h th~ com~n~n moci~
~lgnal remov~d.
ra~:?ly, pr~mpl~ r~ 4~ ~nd ~4 ~n~
~3 ~ e ~th~ ~h~n vol~ h~ o~
o~trr~nt 1~ n~ 1y ~nd~pendent o~ oor~
1?erm~bility, wh~ c:h ~n ohahg~ with t~mp~tur~ and ~t~e~s .
I'c i~ ~}~o pre~erabl~ to ope~a~a ~hio ~yst~n 2 o over a wide range o~ ~r~ nc~ uah a8 from ~ ~o 200 k~. Th~ h~yh~r ~r~quen;:ia~ 2Ichif~lv~ ~en~ltivlty ~or lnveetig2~ion of higb r~ ativlty ~ormation~ but ir ~ on~ r~ul'c ln oxo~ pro~as~tlon )"~
ar~ to~tlon ln low re~lst~v~.t~oOE, t~l~h mi~roproc:e~or 4~q ave,ilable, the P~ogu~3n~y c2~n bo Ad~ua~ed to m~intain ~daguats ~3n~aitivi~y ~
~on~ ont dept~l o~ ~nve~ti~ation wi~h minilnum ~icin-a~eot oorr~ction. A pr~ rr~ m~thod o~ ~chieving this ~lexibillty i~ ~o use bro~d. band 8i~nal ~orld~tlonlng e~e~tr~nl~, elim~nal~ln~ ~ho na~d ~oX
mul~lpl~ ~llte~r6 and aau~ phh3e ~rur~nt ~t~o~lon, tb~r~by pr~0e~rlllg botll a~pl 51 tu~ n~ ~ha0a o~ ~ha oi~nal ~lthou'c clon'ca~ln~ n by ou~;o~ nn nol~.
SENT BY:~AKER HUGtlES, Hou9ton; 9- 5-91: 12:12; ~AKER HU(3HE5~ 91613232344~;#19 2 ~ 3 In ~d~ition ~o ~he ~bili~y ~o oE: ePra~e ovqr ~id~ 0~u~nc:y r~n61~ wi~out ~g~at~c~n, thi~
appro~h perml~ ~lmul~neou~ an~ at multipl~
~re~uanciof~ by ~rAn~m;lttins~ s hZ!~mon~ Qh wavo~qxm.
For in~naa, wi~h ~quare-wa~re ~ive ~nd a ~oann~ng ~ynohrc~nous del~e~tor Arr~ tha~ ~ampla~ ~h~ ~ign~l ln ~on~ uo~ ne oegmont~ h l~ h v~ ~ ~yc~ lon~, th~ amplitu~e and p~aoo c~ the ~und~men~l, th~rd, ~1~th ~d ~ nth h~monio~ may g~ o ~l~t~nin~l. A
~ known teol~nl~u~ wh~h oould be u~ 1 would ~o th~
Fa~t ~ourier Tr~nE:~rm m~thDâ. Tha rQ~pon~o clould al~o b~ analy~d u~ g ~ d~ 0~ion m~tho~
tr~sn~ ~ en~ ~ n ~h~ time ~omain, oi;~ ~our~, rAthor t~
~lr~ ~r~n~ ormin~ i~ into the ~quon~y ~lomail~.
1~ ~t w111 b~ appar~n~ Xrom ~h~ v~ that ~h~
.~nvent1o~ an app~atu~ And ~ me~hod ~o~ a now approaqh to r~ tiv1 ty m6~urement whi~h ~an b~ u~d ~n an ~WD ~oll~ hout we~lcen1n~ l,t. ~aca~ls~ o.
th~ uni~e riold p~ct~rn whioh ~ ~re~t~ad~ ~he sonsin~ el~m~n~ a~ b~ plRc:ed m~1c:h ~:108~ to ~hQ
80u~0~ m~3n~ ~han in oonves~1OnAl indu~tlo31 c~
Rl~trlo~l ~pproaoh~ hl~ pe~ very ~hort ~sombly, oJ~-ha1~ ~o ono-~our~h ~h~ l~ngth o~
conven~lonal P~ re~isti~ y lo~ nd lowe;r pow~r c:on~ump~ion be~au~e o~ the ht~he2 ~ nc~y oP
m~n~t~c-~ored ~ntennn~ and tho shorter pa~h trav~3lled ~y lnv~t~i tion laignals~, It ~Yill al~o be ~een th~t antenna~ oan b~
plA~ed in con~igurat1OIlQ d~lgnod to re~lv~
3 o oir~lm~er,~ntlal inhomog~n~lt1~ o~ r~ tivllty, ~uah ao a~e ~n~untere~ in dippin5~ b~d ma~ur~mentA, uo~ ~h~ inv~ti~Atlon pat~ern~ ~r~s no~ axially sy~ t~1G, ~y comb1rl1ng csl~alsn~ls wlth d$~ron~
w~iyhting, pa~l:a~n~ o~ varl~u~ r~olution~ and deptb3 o~ inv~a~ig~on ~n be ~ynth~ d ~lmult~n~ou~ly.
SENT BY~AKER HUUHES, Houston; g- 5-91; 12:13; BAt~ER HU~HES~ gl613232~440;#20 - 2 ~ 3 1~-The use o~ ~ymmetr~ n~nn~ ~r~ay~ 0~ th~ ~nvon~lon p~nnits r~olution o~ !~eddin~ pl~nea p~r~ or ir~cl ~ n~d ~o B tool axi~ ~ ~h ~ ~ prop6~ y pA~icula~ly ~lua~l~3 ln hor$zon~1 drilllng ~o~o i~
~ equently de~r~bl~ to dtlll 21t A ~on~nt d~t~n~e from ~ome lnter~ac~
~e balAna~d con~l~ur~tio~ o~ s~ec~ivlng ~ntenn~ provld~ by ~oma implaraenta~iorl~ or ~he in~ an~ ~nv~n~lvn ~ lt3 in ~ 6~ron~ oo~Nnon-~node rospon~3 to the prim~ry ~lald, *aailit~illg oo~put~-¢ont~oll~d n-Jll c:ompsn~ation. Th~ nnin~
~ynahronous ~tea~o~ ~rrAy allcsw~ ~;lmultanoc~u~
analy~ t mul~iplq ~requenoleE~ or analy~ n th~
tisna domain .
~l though th~ in~n~on ~aao b~en ~soribfld in oonnsotion ~i~h pre arre~ ~mbod~msnts, ~ ~ wlll b~
reo~gniæQd by ~hos~ ~kill~a in thQ ~rt ~ha~ varlou~
oh~nge3 ~nd v~ria~ion~ can b~ m~ae ~nd ~:hat ~e prlnc:ipl~38 Are ~ppli~2ble to ~y roel~tlv~ty ~o measurem~nt geometrl~. For exampl~, ~t ~n b~ useR
ln convention~l ~ nduc~ion log or ~ on~igur~ton~
by ropla~:ing ~ach un~ercut ~olenoid by a ~oll~
~ontaining ~v~ral magne~ic-~o~ xial antenna~ o~
thel inv~n~ion in ~lo~ uch arran~m~n~ WOUld ~RV13 v~rt~l~lly tlle ~me r~pons4~ ~ th~ orl~ln~l~. Th~y would ben~it from thR ~ull-str~ang~h collar ~n~ ~rom tho minl~n~1 expo~ura o~ inoulatitlg ~aterlal to ab~At~on .
I~ will b~ r~alizod t~ hg~ pr~ ry ~iel~
p~ttern oould be ~ynthesizad by ~ivlng ~everal slelnen~s simultanebu ly. Th~ wnuld m~dify ~he null looi and the plac~men~ of reo~iv~n~ ~nter.n~.
Moreovor, re~lving an~ennas oould ?o~ lo~a~ed in po~it~on~ that elrs no~ assoo~a~ed with null~, ~nd SEhT BY:BAK~R HUG~ES, Houston ; Y- 5-91 ; 12:13 ; BAKE~ HU~HES~ 91613232~440,#21 2 ~ 3 Approp~îR~e wei~htlng o~ mult~ple ~lem~nt~ to a~hiove can~ a~ion ~uld be u~ed, as in oon~entlonAl ~ 8 ~t 1~ thare~ore int~nded th~t tll~ cov~ra~ ai~orde~
applioo~nt ba llml~od only ~y th~ clal~ns ~nd ~h~ir e~ ralant~. .
~urrounding ~eld~ and th~ propa~z~ting w~ nod~
mu~t b~ ~on~3~d~red. AltAoug~ ~e ~eom~'try in~truma~ g~ne~ally æimil~r ~o that o~
c:onven~ional lnd~lctlon in~rumQnt~, ~he o~allow~
unde~ut p&rmit~e~ by it~ high~ s;tuen~:y oper~ion ha~ r~33u~ d ~n i~ u~e wlt~ s~ndard ~WD ~oll~r~. .
SENT B~':BAKER HUGHES, Houston, 9- 5-91; 12:02; 3AK~R HUGHES~ 916132328440;# 6 4 ~
Howqv~:, th~ ~ttenu~ion or WelV1~8 ~rav~lllng in a conductirlg fo~ tion inara~ wlth Pr~ 4n~y. ~he re~;ul~ ~a6~ be63n EW~ ~rran~R~nt~ provld~ ~ow~ d~th o~ inY~ lg~tlon in low ~oi~t~vitl~a ~h~n ty~lo~lly arQ of ir~t6!~e~. A~ ~n ~xample o~ att~u~tlon, at e~ r~ ity o~ ~ 2 ob~-~o~rED ~ho a~ n~ on ;l~
grQ~t~r ~han on~ de~b~ p~3~ lnc~ ~ trav~ n 'ehis ~or~nec:tion, it ~l~o mu~l; b~ r~m~ e~ ~h~k ~luglrlg ur~ment it 1~ necse~$~ry ~h~t ~hs p~ sr y ele~tromagn~tic: risld w~i~h 1~ inducad ~r~ hr~u~h fluid (~yp~ ::ally csAlled a drillln~ "~ud") ~hi~h is circuln~d ~h~ou~ e ~ hol~, ~rhe p~ n~ ;Invcllntion r~la~ to ~ method and app~2~Atu~ c:orpo~ m4dl~1ed lnduc~lon ~ppro~c:h~ whiCh not only a~n b~ u~d wlth ~n rom~n~lc:Ally c:onduc~iv~ ~a~rl~l ~u~h A~ tln Mwr) d2~ill coll r, ~ut t~k~ adv~n~ag~ o~ lts F~ndu~tivl~y . In ~undunen~æl ~mB, a ~na~ o~ ~p~ot Qi~ t~e ~nv~3n~ion i8 direota~ to ta~e~ng ndv~nt~ o~
tho null locu~ o~ a ~ompon~n~ Or a p~lm~r~f Ghanq~ng magnetic ~leld ~orm~d ln ~ ~ormzltion, and plaalng detecting an~3nne~; a~ ~p~ po~aition3 ~ c~
relativ~ ~o l:h~ nu~l Qna~llng th~ pxl~ary ~gn~tlc ~lel~ to l~o ~ inguioh~ rrom ~he ~a¢on~ry ~i~ld cau~c~ by th~ ourrsnt ind~ed in th~ ~o~m~tion by ~he primary ~iald. Mo~t ~ irA~ly~ ~A~h o~ th~ det~ting ~ntenn~s i~ po~ onl3d rlg~t ~t~ a null 30 as to b~
directly de~oupl~ad i':rom th~ pr~mAry ~i~lcl p~ttern, alimina~ing the n~ce~sity oP c:~ncq~lin~ th~3 p~iIQ~ry ~ial~!l by ~ uo~clngl~ corm~oti~ o~ r~ vln~
ant~nn~3.
T~ tr~n~mi~tlng ant~nr~ ) and ~h~3 d~a~tin~
antenna(~ not po~ n~d circum~rontiA~ly Abc~ut SEN, B~`~AKER ~UGHES, Houston ~ 9- 5-91 ; 12:02 ; ~A~ER HUGH~S' 91613232B440;~ 7 .~ , th~ oll~r. Rakh~, th~y ~ AC:~d ~n corr~sponding groo~s or ~ llk~ h~3 clrill oollar~s escte~ior 3uraV~ hi~ ~nn~otlon, th~
an~nna~ ~n b~ gonarAlly ~lon~t~d an~ bly ~nolude a magn~tlc: ~or~ A~ b~ough~: ou~ ~bov~, ~n t~ p~t 1~ ha~ b~3n n6l~a~ o p2-ovlde rol~tl~fsly dll~lap out5 or groo~v~ ln ~l~o out~r c~a~D~at~r o~ a drlll ~oll~ to, amc,ng o~ r ~cblng~, provido ~&ho non-~olldu~ting cro~ o~tional ~ or ~ho ~nt~nn~ ~:ha~
10 i~ r~uir~ in~tan~ ~mr~n~ion ~llow~ th~
ln~lu~ion o~ ~ magnRtia c~ore ~:o c:ono~ntr~to th~ ~lux, th~re~y re~du~lng ~h0 cros~ c~lonal ~r~A th~t 1 n~ed ~
A~ ~no~h~r ~t3atur~a o~ tha lnv~nt~on, ~ho 15 ~uppo:rt ~u~ture rox ~h~ ~n~nne~ 4trloally ~on~uct~v~ arld ~axrie~ A plu~ali~y o~ sur~nt d~ec~ors bu~ in in~u~ d ral~ion~hip ~h~r~o.
EA~h o~ ~h~ de~ooto~a i8 po~ on~d to fl~c~ ~he VAllUe O:e ourrenl: b~ing x~03iv~1 by th~ ~m~ from ~e ~0 forma~ion~ In thi~ c:onnac~ h~ ~t~c~ors Ar~
po~1~ion~d ~ ring r~di~l pwltion~ ~el~iYo to tne axi~ ~ th~ ~upport struci:uXe, wh~ar~y ~s~b ~a~ct~s A ~i:e~r~n~ valu~ o~ oux~n~C. TheAe cu~r~nts wlll reE;peotively ~low through $ucoe~ roly d~ap~ar 25 lay~rs o~ the Pormatio~. This set ~P ~a6~ men~
then produc:e~ ~n ~e~ima~e of the radi~l r~ tivity pro~lle o~ ~he ~ormal;~on immediAtaly ~d~ ~a~n~ th3 ~orohol~ .
It will b~3 reco~n~z~3~ thAt ~h~ abovqs ~u3:r~n~
3 0 m~a~ur~ng ~ahniqu~ h~ re~ult o~ u~ing a ~h~gnq!tlc ~i~ld sc~urc~ t:hat iCI not axi~lly sy~T~otrio, i. ~., tha$ i~a o~ xlo ~ela~iv~ ~o th~ bor~ol-l ~xl~. ~rh~
o~-axl~ ri31~10n~ip ~ orlo ~r ~or~ o~ th~ ~n~rmaa may ~l~o Allow d~exmlnation o~ b~d~in~ pl~no d~p and ~he dlret~ n s:~ a b~àdtng pl~n~.
SENT B~:BAKER HUGHES~ Houaton ; 9- 5-91 ; 1~:03 ; BAKER HUGHES' 91613232a440;~ ~
~ ano~her ~at:ur~ h~ ln~ ion, la~ a pl~rall~ o~ d,e~ec~t~ n~enn~ ~r p~ovld~ 2t n-amine~l dir~ i~af~h~ ~ pxovld~d by e~oh ~11 havfa ~/i3rta~n c:om~o~ o~a;~aJt~ tlc:oO Blnco 30~, ~hi~ ~ommon mod~ a ~ ot ~ pon~o to ~h~ ual p~i~ary ~iel~, lt ~oe~ not helv~ to ~ oomp~n~atsd ~or ~h~ fir~t-order ~ ct~ ~ mud r~ ti~lty, oDl~Lr ~smp~a~:ure, ~rivo ~mpl ituda, e~ n~ are pr~ide~ ~o ~n; ~ th?3 ne$~ v~lra o~ in-phe~
0 ~n~ r~ture c:o~o~s ~od~2 in~ the~ m~in sl~n~l ~hAn~l to ~omp~n~e ~or tll~ ~ac:ond-ord~ ull rs~idu~
'rha primary ma~net;io ri~ld, ~a~in~d ~ th~t ~ 1d wh~c~ ~xi~ in the ~bsen4e c~ arly aon~u~ting ~oxmatlon o~ bo~hole ~lul~ o~mpo~ ld mad~ up not only o~ th~ o~ ed ~y ~h~
tr~ mittlng ar~enna, but ~130 by ~ d ~at~d J~y th~ c~ric~l our~ent induc:~d tr~ ~h6~ ~onduc:tiv~3 ~rlll col~a~ l.
Th~ prim~ry ~iQld p~ttern o~ b~ aynth~i3ed by gi~ sev~al tr~omltl;ln~ ~nt~nn~
eimul~;aneou~ly~ ~hi6 mod~ h~ null lo~l and, hence, th~ pi~c~em2n~ o~ ~ho datocti~g ant~lnna ~o~ .
Moreo~ror, plural null locl oan ~o roxm~d to permlt more ox~noi~re ~i3trlbution o~ ~etQ~éln~ ~n~nn~s.
It i~ al~o pos~ibl~ to pl~oe! aàditionAl dat~oting ant~nnaa in po~i~10n~ ~h~ ~r~ no~ ~alec:~d ba~ad o~
the null loc::i, U~in~7 ~p~ropriRt~ w~algh~ln51 Or Inultip~ lqmen~s ~c aohi~vl~ c:anc~llat~on a~ ln corlv~ntlon~l 10~6.
W~ th ~fe~enc~ to th~ ompanyin~ th~ e~t~
~f drawlng~:
SENT UY:BA5~ER HUGHES, Houston; ~- 5-91 ; 12'~4 . BAK~R HUGHES~ 91613232844~;# 9 .
~ O ~ ~
t'~
~.
. . -7 ~IG. 1 i8 a ~hem~tlo, broken ~ q~ elevs~on i $ ~ 3`~ - b~ T'I;~r~ 3 ,. , , . ~~;: , .1~;?1 /t~q ~ t~q~ r~ r~i~? ~
, . . i, :- : , ,' "`,. ,' ~ .i.?.. ~ 3 ? ~ q~ r~ ; Si ?~
,' ' ~ . ' ;'/ ~ ~'' ' , , ` ' ~' .. ' " .;~ '`
. ~ . .
SEN~ ~Y:BAKER HUGHES, Houston; 9- 5-91; 12:05; BAKER HUGHES~ 916132328440;#1~
a;
FIG. ~ , A seC~ oJl~l viaw ~imil~,:r t:~ FI~. 1 taken on a plane in~i~at~d by ~e ~in~ llA~A in ~I~. 10;
FI~ Ano~hor ~ct~on~,l vi~w ~Aken ~n a plan~ indi~ d ~y th,~ lln~ in ;~ . 10 7 Bn~
FIG, 1~ oh~,mAtl~ bl~ok di~g~m ~rl@~ o~ a p~er~d r~oe:l~ing ~h~nn~l o~ ~he ~n~ ntt~n.
~IGS . 1 ~nd ~, illu41trat~ the ~undAmantA~`
lo prin~ipl~ o~ ~h~ stAnt ln~r~n~l~n, ~nd ~. 3 inalud,e~ r ~ b~ a~ us~der~t~nding o~ th~ ~am3.
Wlth r~r~n~e ~o ~I~S. 1 ~r~d ~, ~ w~o~na~ia r~pr~en~At~On 11 o~ ~ metal ~rill c:oll~
~llu~t~at~d, As t~ known, ~U~h ~ dr~ oll~r i~
~5 located b~tw~en th~ drillln~ ~t~ or pip~ ~nd th~
drlll~ng bi~ during th~ forma~ion ~ ~ boreh~
r 11 includ~ a ~ln ~xl~ 1~ which when tho ~tru~tur~ 1E; wi~hin a borehole i~ ~ean'c to b~
gen~rally aoinc:ldent with th~ boxehol~ ~en~r~l ~xl~, 2 o :L . o ., ~ llne ~r~wn centr~lly through ~h~ b~eh~le hlQng its l~nyth. c:011Ar 11 1~ ~ypioal in th~ ik 1 metal, u~d ~or drill ~ o imp~t w~lght and 3~r~ng~h .
MWD (Me~ rç-Wh~ D~ ng) 1~ a~c~mpli~h~d by 2 ~ in~trumentation whlah i~ a~ooiat~ wlth tho ~tAl drlll ~ollar. ~8 ~nention~d abov~, the tw4 ~ppro~ah~
whioh h~v~ been U8B~ he pas~ to m@asu~ the re~i~tivity o~ ~ :eorm~tion aurroun~lng th~ borehole h~vo no~ b~en ad~ptod ~a~ torlly to MWD
3 o op~ratlon . ~n~ ~ea~n fo~ ~hi~ ia ~hAt, b~aau~ h~
dr~lling ¢oll~r typic~lly 1~ el~Gtrlcslly conduat~vs, induotior~ type ~pproa¢h~ hav~ ~e~ r~lativ~ly SENT BY:BAKER HUGHES, Houston , 9- 5-91 ; 12:~5 ; BAKER HU~HES~ 91B13232~44~;#11 , g de~p circ:um~er~n~ial yr~ov~ t~ ~e ~ortned ~n th~ dril 1 oollar to hc~u~e th~ ~n~e~n~(s).
~he pr~on~ invantion ~ak~ d~nta~o o~ 'eh~
~l~ctric:~lly ~nnduotiVe natura o~ ~h6~ Ll asll~r.
I~ has been ~ound ~llat i.~ ~he ~r~ mit~in~ ~ntonn~
i~ po~ltlon2tl o~ xl~ o~ th~ m~in ~XiB 0~ th~
~ol ~ a~ ., radi~lly o~ om the b~hol~
c6!n~r~ axi~ a ¢h~ngln~ prlmary ~ n~ ield iE~
îonn0~ w~ioh ~aa3 loa~1 o~ ~x~ oo~nponont mlni~a on lo th~ ooll~r l3ur~ , That ie, a "prlmary" 3i~as~n~tic f isld 1~ f~ 3d whioh hfl~ ~ lo~t~on ~t whi~h th~
diraati~n o~ th~a ~xia~ ~ompon~n~ o~ ~h~ ld nomin~lly ~ n-ph~e~ wi~h ~h~ allt~nn ~l~ld wil~
~ve~ h~ loou~ o~ tbi~ x~Ye~al 1~ r~er~d t~
1~ herein ~8 a "dlr~a~ional null . " ~inae the ~gn~tio gi~ld o~ ~h~ tran0mlt~1n~ ~nt~nraa indllaa~ a cur~enk in tho metal ooll~r lt7~ th~ prlm~ry m~gne~i~
~i~ld a~ u~e~ }~ex~in ~ a~tu~ a c:omposlte ~l~ld m~d~ up by the ~up~rpo~ition o~ sna~n~o ~i~ld 2 0 c~a~e~ by tha tr~n~mittlng ~n~nnA dl;E ~ctly, an~l the ~Gondary ~ reated by th~ qur~ whloh i~
induoed ln th~ condu~lng ~oll~r~
Mo~t ~sirably, ~ r~ns~ lng antennA ~ 18 loo~od on or n~3Ax a ~u~ e o~ th~ drlll 4011ar by, f~r ~x~mplo, ~lng plaosd wi~hln ~ groov~ A5 lllustr~ted, A~ ~3hown ln FI~. 3, auch ~r~n~mitt~ng an~enn~ ~ylln~rio~l or / /~
rod ~hap df~(elaat m~ ~or~ 14 wh ~h iB 4pir~11y ~/V r, wr~pped wlth c~ndu~iv~ wire 15. ~hlo ~ono~ruc~t~n wlll reBult ~n optl3~um ~lux tr~nsr~ls~ion ~lno~ Plux ~ ~7G
ln ~h~ ~nt~nn~ i~681~ ~o~m~d by csurrent ~lowlrlg 6 throu~h the w~ re lS wlll b* c~onc~antr~t~d by th~ ro~
1~ .
SENT BY:~AKER HUGHES, Houston ; 9- 5-91 , 12:06 , BAKER HUGHES~ 9161323Z~440;#12 ~ has been ~ound that a d~rRc~ional mlll r~p~ ted at 16 will b~ ~oxm~ on l:h~ ~}r~e o~
the drill ~ollar ~lr~um~e~ntiall~ ~bout th~ ~am~.
~n k~eplng w~th ~h~ lhv~ntiorl, th~ d~t~otin~ Qntenna ~or det~ct~ng th~ ~ield produ~ed by l:he c:ur~ent lndu~d ln th~ ~orm~tion i~ poQ~loned ~t a lo~a~lon relativ~ ~o ~uoh null ~t whir~h ~uoh ~ond3.ry magn~tit~ ld 1~; di~tingul~hable ~om ~he p~ na~y magnetlc~ ld. Morsov~r, ~ox m~Xim~m t!l~pth o~E
1~ ln~.rs~tiga~ion ~rhen a ~lngl~ de~:~c~ing ~ntennA i~
u~ed, ~ t i~ p~Pe~A~le tha~ lt b~ di~m~ a~lY
oppoai~e ~h6~ ~ransmi~ting Qnterln~. Antonn~ 17 i~
~uc~h a d~t~ g ~nt~nna. ~t~ ~on~ltrua1:~.on 1~
~imlla~ ~o that o~ the tr~n~mit~ing ~n~nn~ 13. Mo~t d~sl~a)~ly ~ t i~ deooupled ~r~ h~ pri~nary m~g~e~
~iald by beln~ po~ icnad rlght ~ null~ muE;~
b~ r~m~m~o~ ough, that: ~u~b ~.ek~ln~ ~nt~nn~
h~ a ~lnit~ l~n~th, nn~l wh~n th~r~ ou~olon ln thl~ ~oo~m~nt a~Du~ po~i~ioninsa ~e ~ lny Oy~O~n 2~ ~t th~ null tk io ~eanl: po~ ion$nçl th~ d~t~ting an~nni ~or nominal z4ro ou~5~ut.
Although ~ per~e~t ~root~on~l null ~heor~ti~ally wlll o~.cur, tl~ with ~h~ u~nptior that th~ colla~ iB a pGr~s~t: oonduotar. ~hQ
pr~ct~l Oel92 C)~ ~inlte c~nduotl~rl4~ r~u~t~ in ~
~rQry do~p mlnimum, bu~ with ~ome r~dual qu~d~Atuse oomponon~ whiah mu~t be com~ç~n~ato~ ~or to as~ure p~oper opex atl~n .
~i~ld lln~ 18 ~ra ~uperimpo3ed an th~ drswlng 3 o ln FIC . 1 to ~how ~he natur~ o~ ~h~ ~rimary ~Dagnetic fi~ld. ~hi~ ld i~ a ~omposi~ o~ tho ~-ld cFe~ted ou~side t~lo collar by th~ kr~n0mittlng ~ntenn~/ an~ a pro~ction on tne ~lane og ~uch Xleld, o~ tA~ ~econdary fleld cau~ed by Guxr~nt induoe~ ~n th~ con~uotill~ ool1a~D A~ ~hown, ~ iald ~t th~
SE~T BY:~AKER HUGHES, Houston; Y- 5-91; 12:37; E~AKER HU~ES~ 9161~232~440;#13 205~vn~3 ~aUX'~AC:e and Oultgia~ tha c~ollar iri ~h~ ~rD.n~vorse b~ tlng plane o~ ~h0 ~r~n8mitti.ng ant~nr~ 13 i~
ev~ywh~e axial an~ dlr~ot~ oppQ~1t~ly ~o th~ ld ln the ~ntenna oo~ will be ~ec:ognlz~d that th~
dixa~tlonal hu~l 10~UQ in ~a~ lr~um~ ib~ tha m~tal c:ollax. Mor~ov~, ther~ will be two null lo~li th~t e~Q ~m~d ~bou~ a plan~ bi~ ing tho tran~mlttlng antenn~, Ax~slly ~y~Nne~r~O o~ ~h~ 0411~r 11 r~lAtiv~ ~o the ooll~r m~ln axl~ la o ~l~ul~n~ou~
10~s~tl~ m~u~m~ h~ r6! ~n ~ w~
axiAl ~para~lon. Thase oou' ~ be u~d ~ r~y elem~n~ ts ~ynthe~z~ dl~eront in~e3ti~tlon p~ttornR, or on ~ rota~ng ~oll~ to ~oi~
d~t~mlning 2~ppsr~nt b~d~ing pl~ne dip.
15F~G. 4 i4 ir~cludqd ~o ~llitA~ ~n und~rQ~ndln~ be in~t~n~ lmr~n~lon. I~
lllu~tr~t~s ~he fl~ld ~o~ by a eonv~nl:ional wl~
1 ln~ lo6~ arranyam~nt ~ Suoh ?~,xrang~men~ l ncJl ud ~tran~ ter c:oil 21 whlch i8 ~ dded ln a non~
~l~c~ricAlly aonducting, ~loslgat~d body 22~ ~lnco ~uch l~od~ 1~ non-condu ::ti~re, ~h~ magn0tia ~lux pAtte~n o~ ~h~ primar~ ld form~d by the ~ra~mitt~r ~oll 21 will not be "~ls~or~qd" ~y the flxio~tanc~ o~ ~uch body . Although ~or ~i~pl io ~ ty the ~5 ~lux p~t~rn i~ ~nly ~hvwn in ~wo dlm~n~ions, it will b~ r~co~nl~d ~hn'c ~here i.B 11 th2~0~-dlm~n~lonal ~lux patt~n which i~ ~imply ~n Axl21~ rla ~igure O:e r~volution o~ that ~howr~, ~ co~vent1onal Arr~ngoment as P,hown in FI~. 4 3 o typio~lly 1nalude~ two ~epar~t~ r~o~lver coil~ .
~e6e ~o11~, repr~en~d a~ 23 an~ ~4, ~ po~tioll~d on th~ body ~o that ~he ~urr~nt in~uc~d ~n the ~am~
wlll ~o in ph~E3e. Th~ ~mplitu~o~ o~ t~ ou~ont oallsed by the pr$m~ry mAgn~io ~ld will 1:~
appr~xlmat~ly inve~se to ~h~ ~ube o~ t,hoi~ ra~p~otiYe SENT BY:BAK~R HU~HES, Houston, 9- 5-91, 12:~8, ~AKER HUGHES~ 91613232844~;#14 2 ~ 3 dl~tanc~ ro~n the trah~mi~i;ing ~:oil ;~1. To ellmln~ primary ~i~ld biaEI o~ k~le ~og outpul:, I;hb ect c~upl~ny ~ 4h~ p~imary ~ ld io c~nc:el~ ou~
l~y ~ g ~h~ appropria~oly w~i~h~od t3~ oo~ ~
IBign~ll8 induc~d in ~he~ two noil~ . ~n ~l:hær word~, lt ~ nac:¢2~ary ~o h~rs two r~celvin~ ¢oll~ to enahl~
elimtna~lon o~ prim~y ~leld b~Ae. q!wo r~aivlhg cc~ils ~re no~ nec:es~ry ~02~ the in~t~nt lnvontlon, ~lth~ugh, 1~ d~lr~d, ~nultipl~ Clet~¢ting (o~
~an~rqitt~ngJ ~n~nna~ ~ay be u~ o ~yn~h~s~n di~or0n~ depth~e~olu~ion ~ t~3~n~, ~o~ove~, ~h~
~ah~me ~ h~3 ln~ta~ lnvontion enabl~3s on~ to p~.AC~
~h~ ~et~a~lng and ~an$m~tt~ng ~s~n~enna~ ~u~h olo~or ~ ~n~ Ano~h~r an~ t~es muoh 1Q~Et POWeX th~n 1~ conven~lonQl a~ran~ment~
F~Gs, 5 and 6 illustr~te a ~lmple ~r~Ay u~lng ~wo t~An~ tlng a~tonnhs ï3~ wh~oh ar-a dl~Jnetri~
oppo~d to one ~no~her and ~wo ?~ceivlng ant~nn~ 17 w~ioh ~ alEso diamots~tcally oppog2d to on~ Anothor~
2o but ln a plano pe2~pendi~ular ~o ~h~a p~an~ o~ th~
tran~mltting antOnn~B- Th~ Islmples~ ~lectrii::al ¢on~lgur~ on ~o~ thl~ arr~y 1EI on~ in whic:h a~oh antenn~ pair i9 oonn~q~ed oithe~r in par~ l o~ in 3erl~, r~ ltlng ln ~ oin~l~a tran~sm~ttln~J ohannol an;l a olngle reGei~r~ng cn~nn~ hl~ g~m~t~y i~
0ensiti~e to ~ircum~ren~i~l inhomog~n~iti~s of ~orm~tion r~ stivity ~h~n th~ un~ rlc:~l configuratlon illuetr~t~d in F~G~3. 1 and 2 .
Mor~over, it has #omewh~t bQtter ~hln-l:ed r~solution.
~y the ~lmplo expodlont o~ fl~teot~ng th~ 3~gn~13 fro~n the two r~c:eiving ant~nna~ ~e~arat~ly and cclrrolating Wit~l rotation durlng rotAry drllling by, ~or ~x~mpla, u~ing dat~ rrOm ~ixeot~onal ~en~o~s lncorpor~od 1 thQ tool, ~6ddin~ pl~ne dip ~nd ~ik~ ~an be 3 5 resolved .
. . .
SENT ~Y:~AKER HU~HES, Houston, 9- 5-91; 12:~9, BAKER HU~HES~ ~161~232~40,#15 The ue~ Q~ a tran~mi~tirJ~ ant~nna ~h~t i~ not ~xiAlly ~y~nm~tric provi~ a di~e~anlt ~pp:roAah to r~ vl~y mea~ure~ment. FI~. 7 ~ olud~l t~
~cili~te D.n und~3rotandlng ~ thi ~ appro~c:h ~
d~piotoe lin~g ~epresontln~ th~ el~a'cr~.~al ~leld ndu~ed by ~he primary mag~tla ~i~ld t2~ ~he ~ioinity ~ tho o~n~r~.l plan~ of a t~ansmi~;ln~ ~nt~nn~ 13 in ~ dr~ ollar r~p~e~antæ~ in eros~-~eetlon. .
Th~e ~lectria ~eld lines sre ~uperi~po6ed on l:hQ
~adl~l re~ r~ty z~na~ that ~asl ~ di:~erentiate~
ent a d~;llling ::oll;~r ln a bo~eh~ xosp~ ~or di~tor~ion~ ~n~roduced by boundary ::onditl~n~ b~tw~bn ~on~ ondu~on ou~ront~ w~ ll k~nd to follow ~h~e ~l~ct~ioal ~iel~ . A~ illu~tr~t~3~, all c)~ the hybrid aurrer~ pa~h~ aro ln~er~ept~ y ~he aoll2l~ at a normal in~id~nce r~sluixæ~l by ~t~ h~gh o~nducl:lv~ty~
~hi~ ~omplet~ th~ c:los~d ~:~ndua~lon p2lth~ . In k~epin~ wi~h ~ inventlon, ~n ~rr~y o;~ el~trQd~ 31 arQ pooitlon~d ~o tnte:rc~pt th~s~ cu~ren~, oach o~
o whi~h will ~low through a ~uc: ~a~ ely de~p~r laye~
of the ~ox~nati~n. I~h~ B ~rray i~ b~t ~ JB1:r~t~ in ~IGB. 8 ~nd 9. I~ will b~ ap~ro~a~ that ~o~ o th~0~ elec~ro~eE~ in~ul~tad rrom the ;:~lla~ ' ~u~a~ ~ut i~ ~nalntaino~ at ~h~ ~oll~r pot~ntlA~
~et o~ m~sur~ments o~ ~rolt~eo x~ ul~ing ~roYu those cllr2~nt~ will produc~ 2In ~stl~te of kho radial re~lotlvity p~o~lle t~ ~ ~apth or oeVera~ G~ r radii lnto tho ~orma~io~. It ehould be noted tha~ ~
althou~h the Array o~ ~lo~ro~ ar~ aho~7n in 3 o partlc~ular po8itlon~ on ~h~3 ~ollur ~u~ce ro}~lva ~o ~ho trAnsm~ ing an~nna, other poa~ion0 on ~uoh 8Url~2!1C:4 ~Dr ths ols30trodeo could b~ cted, dopenAlng upon ~h~ rrent i~ i3 t~ c31 tC~ -int-r~ept .
3 5 ~t~tg~ thAt ~h~ hybrld ~urren~ paths illu~tra~d ln I~G. 7 are radi~lly well c:olliJn~sd ~nd a~n .
SEN~ BY:BAK~R HUGHES, Houston , 9- 5-91 12:09 ; BAKER HUGHES~ 91~13232~44~;~16 2 ~
~4-thqr~ ro provi~ ~xa~ nt b~3d~ing-pl~ne ~olutionO
tn ~pl~a of pr~iding r~ iv~ly oh2l110W
inva~tlgA~on, ~hi~ mea~u~m~n~ ~ uo~u~ ~or llthogr~p~y while lnv~lDn 1~ ~till ~allow. Al~o, th~ hybri~ pro~ilo i~ U8e~l~Ul ~or bo~ohol~luid ~o~rectlon~ of ~h~ ~4~p~r ~n~re3:~iç7atlon pro~d~d ~y th~ lnc!~uc~orl mod~ o~ ~he B~m~ c:on~igu~;~tl~n.
~oreo~rer, i~s radial re~olution should ald ~tlm~tlon o~ ~oxma~ion p~ ility hy t~aoing th~ p~o~o~ O:e in~ra~un~ par~ioularly whan ~ pre~ 3usly-drill~
in~er~ lo~g~d b~k du~in~T tri~ping.
~I~S~ 10 through 11~ sllow ~ pre~r~d a~r~ng~ nt ~olnh~ nin~ b~th the D~gn~ n~ng and ourr~n~ ~en~ g ~spe~t3 o~ ~be lnv~nt~on~ A
tran6mittirlg xrl~nna l~ ~ep~e~ent~d ~ 13 " ' .
plurali~ oX d~tecting a~t~nn~ ~7 ~ ' ~r~ po~itlonRd cir~um~er~n~lally about ~h~ drill coll~ ~t ~As ~wo oi~auD~ 2ren~ial di2q~etioh~1 null~ ~orm~a on op~o~lte ~lde~ o~ th~ tran~mlttlng ~nt~nn~. ~or~ov~r, a plur~lity o~ ~e~o~tors 31~ Are po~ltl~ne~ ~o ~et~4t ~urr~n~.
The unlque g~o~netri~o 1)~ th~ inv~sntion pormit the ~10e of magne~io ex~itation wi~h c:urrent ~ensing 'ch~t ~eln ~ oonstxucted to h~ ry hl~h 2~vlutio~
both radially anfl ax:L~lly. Although limi~ed ~o ~latively ~hal~ow inv~tl~e~tlon, 1~ can be U~ to resolve lnva~lon pro~lleo, co~ ens4~Q ~or borol~ol~
~ect~, ~nd resol~re thin bed~ in fl ~re~hly-drilled hol e. Th~ ao~bin~tlon o~ magnetic~ n31n~ ~Y;Lth 3 ~ ~ ndu~d c:urren~ sen~ing ~esults ln ~n arrangem~nt which p~ovl~es both ~hallow ~nd d.~ep ln~o~tig~iorls.
Anothar ~ature o~ th~ in~ n~ insrentlon is th~
pre~ncQ o~ a common-~ode ~ignal ~2-om ~aoh ræoo~ring ~ntenn~ ~h~t o~n ~e u~ed kc~ ~u~pr~ h~ re~ldual SEN~ ~Y:~AKER ~U~ES, ~ouston, 9- 5-91; 12.10; ~AKER HUG~ES-~ gl~l3232~44~;~17 2 ~ 3 primary-pi~d respon~ ~o ~ho nomin~l dlreqtlon~l null. slno~ thi~ o~mmon mo~ diroot ~e~pon&e ~o the ~tual p~lm~ry ~i~ld, aom~na~tâon ~o~ not hav~
to ~a mAde ~or ~ho ~ t-Qxdor o~n~ o~ m~ld ro~i#tivi~y, collar t~mp~ra~u~e,. ~rive ~mpll~ude, ~t~. In~tead, ~ ml~rop200a~0r c~n~roll~r can b~
provlded ~o ~n~ ~o~ th~ n~a~ y lev~l~ oi~ ln-Rh~e An~ tauadr~tura common-mode ~nt~ th~ ~aln ~gnal c:hannel ~o c:l~mps~nsA~e ~or ~h~ ~oaon~ and hiSlhor o~dor null ~e~iduals, ~ollowing 2i ~ao~al oon~t~ t~ rom t:QBt me~sur~men~ Xn othor wc~ ho d~t~c)ting ~ntann~ ~n ha~re a ~c~ntro;l.l~x ~or addin~ eon~kant char~c~ri~ s o~ a E~ign~l ~o ~h~ cu~en~ lndu~ed :ln th~ ~am~, to ~o~peno~te ~or ~ign~l o~ara~t~rl~
1~ ~aus~d by t~ rim~ry m~n~ iol~.
~G. 12 s~hom3~ioally ~llu~rat~o ~uch ~aoelv~r channel, ~h~ ~urrent indu~d ~y the pr~m~
f ~ el~ ~aa6 a 81gnA1 value over th~ len~th o~ tb~
re~lv~n~ ank~r,n~ ts) . ~ow~var, in ~ho pr~rr~d ~o &rr~ngQm~ hq roceivin~ ~ntannat~ ~pan{E~) ~
~ire~on~l null. ~uoh an ant~nna, r~r~ent~ t ~1, ie aoupl~ to a ~z~in ~l~nal p~eampll~l~r g2 through ~ ~ran~f c~ r 4 3 with ~ c:ant~ pp~ p~im~ry windinq. ~ince th~ ~ur~b~t lnduc~d by tho prima~y ~lold r~v~r~e~ po~rity n~ar ~ nt~nna con~ , the Comm~ mode ~rolt~ge be~w~n the ~ntennn eLnd trane~ormer C~e~tQr ~ap~ Will be proport:l onAl to ths ~u~n o~ gnltud~ o~ th~ r~pon~e o~ ~-h~ ~n~nna halves to the priTnary fia'~ d. ~hea~e wlll ~ oan~ele~
3 0 ~o khe ~lrst ord~ar. At the ~ame tlm~ h~ ~ec:ondax y sign~l~ o~ in~ereet will be in ph~s2 otrer th~ l~n~h the ~ntenna, cr~tlny a dl~tr3n~i~1 8i~nal that lve~d to lthe sl~n~l pr~ampl~ r 4 conunon-~node pr~ampli~ 44 i~ connec~ed ~we~n th~
oant~r ~p~ o~ ~h~ dato~ttn5~ ant~na a~ illu~tr~tsd.
It ampl~fies l:ha prl~nary ~ield r3plioa1 wi~h thæ
SENT By:BAKER HuaHEsl ~ou~ton; g- 5-91: 12~AKER ~U~HES~ ~1613232~44~
2 ~
~16;
la~oollda~y rs3pon~e s: ~noel~hl~ p~ mp~ r dr~v~ ~ pais~ o~ m~ opr~or-~on'croll~
Att~nU~ 4~ ndl 47 ~th~r~p~ooae~r l~
r~p~ n~ld ll~ 4~ lllu~at~ rullto~ ~7 ~v~n b~ ~:ho pre~mpllP~o~ 4~1 ~hrou~ ph~
ng ~a~2t~ork r~pr~ od çlt ~ g~nua~or~
4B æ.nCI 47 l~pl~men~ ~h~ mc~dRll~ oond order p~im~ry ~1 ald ~irelction~l nulls prov~ by the microprc~ s30r oontro'~ he ~ig~ sre ~umm~d with th~ output ~ror~ ~he m~in ~lgnal pr~ampli~ie~ a~
i~ xepre~ente~ ~ 51 ~nd 52. ~ outp~lt ~n~
th~ d~lr~d d~teation ~ ~gn~1 wi~h th~ com~n~n moci~
~lgnal remov~d.
ra~:?ly, pr~mpl~ r~ 4~ ~nd ~4 ~n~
~3 ~ e ~th~ ~h~n vol~ h~ o~
o~trr~nt 1~ n~ 1y ~nd~pendent o~ oor~
1?erm~bility, wh~ c:h ~n ohahg~ with t~mp~tur~ and ~t~e~s .
I'c i~ ~}~o pre~erabl~ to ope~a~a ~hio ~yst~n 2 o over a wide range o~ ~r~ nc~ uah a8 from ~ ~o 200 k~. Th~ h~yh~r ~r~quen;:ia~ 2Ichif~lv~ ~en~ltivlty ~or lnveetig2~ion of higb r~ ativlty ~ormation~ but ir ~ on~ r~ul'c ln oxo~ pro~as~tlon )"~
ar~ to~tlon ln low re~lst~v~.t~oOE, t~l~h mi~roproc:e~or 4~q ave,ilable, the P~ogu~3n~y c2~n bo Ad~ua~ed to m~intain ~daguats ~3n~aitivi~y ~
~on~ ont dept~l o~ ~nve~ti~ation wi~h minilnum ~icin-a~eot oorr~ction. A pr~ rr~ m~thod o~ ~chieving this ~lexibillty i~ ~o use bro~d. band 8i~nal ~orld~tlonlng e~e~tr~nl~, elim~nal~ln~ ~ho na~d ~oX
mul~lpl~ ~llte~r6 and aau~ phh3e ~rur~nt ~t~o~lon, tb~r~by pr~0e~rlllg botll a~pl 51 tu~ n~ ~ha0a o~ ~ha oi~nal ~lthou'c clon'ca~ln~ n by ou~;o~ nn nol~.
SENT BY:~AKER HUGtlES, Hou9ton; 9- 5-91: 12:12; ~AKER HU(3HE5~ 91613232344~;#19 2 ~ 3 In ~d~ition ~o ~he ~bili~y ~o oE: ePra~e ovqr ~id~ 0~u~nc:y r~n61~ wi~out ~g~at~c~n, thi~
appro~h perml~ ~lmul~neou~ an~ at multipl~
~re~uanciof~ by ~rAn~m;lttins~ s hZ!~mon~ Qh wavo~qxm.
For in~naa, wi~h ~quare-wa~re ~ive ~nd a ~oann~ng ~ynohrc~nous del~e~tor Arr~ tha~ ~ampla~ ~h~ ~ign~l ln ~on~ uo~ ne oegmont~ h l~ h v~ ~ ~yc~ lon~, th~ amplitu~e and p~aoo c~ the ~und~men~l, th~rd, ~1~th ~d ~ nth h~monio~ may g~ o ~l~t~nin~l. A
~ known teol~nl~u~ wh~h oould be u~ 1 would ~o th~
Fa~t ~ourier Tr~nE:~rm m~thDâ. Tha rQ~pon~o clould al~o b~ analy~d u~ g ~ d~ 0~ion m~tho~
tr~sn~ ~ en~ ~ n ~h~ time ~omain, oi;~ ~our~, rAthor t~
~lr~ ~r~n~ ormin~ i~ into the ~quon~y ~lomail~.
1~ ~t w111 b~ appar~n~ Xrom ~h~ v~ that ~h~
.~nvent1o~ an app~atu~ And ~ me~hod ~o~ a now approaqh to r~ tiv1 ty m6~urement whi~h ~an b~ u~d ~n an ~WD ~oll~ hout we~lcen1n~ l,t. ~aca~ls~ o.
th~ uni~e riold p~ct~rn whioh ~ ~re~t~ad~ ~he sonsin~ el~m~n~ a~ b~ plRc:ed m~1c:h ~:108~ to ~hQ
80u~0~ m~3n~ ~han in oonves~1OnAl indu~tlo31 c~
Rl~trlo~l ~pproaoh~ hl~ pe~ very ~hort ~sombly, oJ~-ha1~ ~o ono-~our~h ~h~ l~ngth o~
conven~lonal P~ re~isti~ y lo~ nd lowe;r pow~r c:on~ump~ion be~au~e o~ the ht~he2 ~ nc~y oP
m~n~t~c-~ored ~ntennn~ and tho shorter pa~h trav~3lled ~y lnv~t~i tion laignals~, It ~Yill al~o be ~een th~t antenna~ oan b~
plA~ed in con~igurat1OIlQ d~lgnod to re~lv~
3 o oir~lm~er,~ntlal inhomog~n~lt1~ o~ r~ tivllty, ~uah ao a~e ~n~untere~ in dippin5~ b~d ma~ur~mentA, uo~ ~h~ inv~ti~Atlon pat~ern~ ~r~s no~ axially sy~ t~1G, ~y comb1rl1ng csl~alsn~ls wlth d$~ron~
w~iyhting, pa~l:a~n~ o~ varl~u~ r~olution~ and deptb3 o~ inv~a~ig~on ~n be ~ynth~ d ~lmult~n~ou~ly.
SENT BY~AKER HUUHES, Houston; g- 5-91; 12:13; BAt~ER HU~HES~ gl613232~440;#20 - 2 ~ 3 1~-The use o~ ~ymmetr~ n~nn~ ~r~ay~ 0~ th~ ~nvon~lon p~nnits r~olution o~ !~eddin~ pl~nea p~r~ or ir~cl ~ n~d ~o B tool axi~ ~ ~h ~ ~ prop6~ y pA~icula~ly ~lua~l~3 ln hor$zon~1 drilllng ~o~o i~
~ equently de~r~bl~ to dtlll 21t A ~on~nt d~t~n~e from ~ome lnter~ac~
~e balAna~d con~l~ur~tio~ o~ s~ec~ivlng ~ntenn~ provld~ by ~oma implaraenta~iorl~ or ~he in~ an~ ~nv~n~lvn ~ lt3 in ~ 6~ron~ oo~Nnon-~node rospon~3 to the prim~ry ~lald, *aailit~illg oo~put~-¢ont~oll~d n-Jll c:ompsn~ation. Th~ nnin~
~ynahronous ~tea~o~ ~rrAy allcsw~ ~;lmultanoc~u~
analy~ t mul~iplq ~requenoleE~ or analy~ n th~
tisna domain .
~l though th~ in~n~on ~aao b~en ~soribfld in oonnsotion ~i~h pre arre~ ~mbod~msnts, ~ ~ wlll b~
reo~gniæQd by ~hos~ ~kill~a in thQ ~rt ~ha~ varlou~
oh~nge3 ~nd v~ria~ion~ can b~ m~ae ~nd ~:hat ~e prlnc:ipl~38 Are ~ppli~2ble to ~y roel~tlv~ty ~o measurem~nt geometrl~. For exampl~, ~t ~n b~ useR
ln convention~l ~ nduc~ion log or ~ on~igur~ton~
by ropla~:ing ~ach un~ercut ~olenoid by a ~oll~
~ontaining ~v~ral magne~ic-~o~ xial antenna~ o~
thel inv~n~ion in ~lo~ uch arran~m~n~ WOUld ~RV13 v~rt~l~lly tlle ~me r~pons4~ ~ th~ orl~ln~l~. Th~y would ben~it from thR ~ull-str~ang~h collar ~n~ ~rom tho minl~n~1 expo~ura o~ inoulatitlg ~aterlal to ab~At~on .
I~ will b~ r~alizod t~ hg~ pr~ ry ~iel~
p~ttern oould be ~ynthesizad by ~ivlng ~everal slelnen~s simultanebu ly. Th~ wnuld m~dify ~he null looi and the plac~men~ of reo~iv~n~ ~nter.n~.
Moreovor, re~lving an~ennas oould ?o~ lo~a~ed in po~it~on~ that elrs no~ assoo~a~ed with null~, ~nd SEhT BY:BAK~R HUG~ES, Houston ; Y- 5-91 ; 12:13 ; BAKE~ HU~HES~ 91613232~440,#21 2 ~ 3 Approp~îR~e wei~htlng o~ mult~ple ~lem~nt~ to a~hiove can~ a~ion ~uld be u~ed, as in oon~entlonAl ~ 8 ~t 1~ thare~ore int~nded th~t tll~ cov~ra~ ai~orde~
applioo~nt ba llml~od only ~y th~ clal~ns ~nd ~h~ir e~ ralant~. .
Claims (44)
1. In apparatus for measuring the resistivity of a formation surrounding a borehole having a central axis, the combination comprising:
(a) a first, axially asymmetric antenna for forming a changing magnetic field within said formation;
(b) a supporting structure for said antenna to be placed in said borehole, which structure has a main axis meant to be generally coincident with said borehole central axis when said structure is in said borehole; and (c) a second detecting antenna for detecting the secondary magnetic field resulting from the electrical current induced in said formation, positioned at the location of a null in said primary magnetic field.
(a) a first, axially asymmetric antenna for forming a changing magnetic field within said formation;
(b) a supporting structure for said antenna to be placed in said borehole, which structure has a main axis meant to be generally coincident with said borehole central axis when said structure is in said borehole; and (c) a second detecting antenna for detecting the secondary magnetic field resulting from the electrical current induced in said formation, positioned at the location of a null in said primary magnetic field.
2. The apparatus of claim 1 wherein said supporting structure is electrically conductive and said first antenna induces electrical current therein, said changing magnetic field being a composite field including the field formed in said formation by transmission from said antenna and the magnetic field due to current induced within said supporting structure by transmission from said first antenna.
3. The apparatus of claim 2 wherein said detecting antenna is generally decoupled from said primary magnetic field.
4. The apparatus of claim 2 wherein there are a pair of detecting antennas, each of which is generally opposed to the other relative to said borehole central axis.
5. The apparatus of claim 1 wherein said first antenna is supported by said support structure at a position which is radially offset from said main axis.
6. The apparatus of claim 5 wherein said second antenna is also supported by said support structure at a position radially offset from said support structure main axis.
7. The apparatus of claim 6 wherein said supporting structure is generally cylindrical, and said first and second antennas are positioned in corresponding grooves in the exterior surface thereof.
8. The apparatus of claim 2 wherein said first antenna is adapted to form a changing magnetic field having a plurality of nulls; and there are a plurality of said detecting antennas, each of which is respective null to enable said secondary magnetic field.
9. The apparatus of claim 8 wherein said detecting antennas are symmetrically located relative to said transmitting antenna in the direction of said main axis of said support structure.
10. The apparatus of claim 1 further including a plurality of said detecting antennas located at differing distances from said first antenna.
11. The apparatus of claim 1 wherein means are connected to said detecting antenna responsive to electrical current induced therein upon the detection of said secondary magnetic field, which means includes a controller for adding constant characteristics of a signal to said induced current to compensate for signal characteristics caused by said primary magnetic field.
12. The apparatus of claim 1 further including means radially off-set from said main axis for measuring from said borehole, the different values of current induced within said formation at respectively differing distances.
13. The apparatus of claim 12 wherein said current measuring means comprises a plurality of electrodes supported within said borehole by said supporting structure at differing distances from said first antenna.
14. In a method of measuring the resistivity of a formation surrounding a borehole at the time the borehole is being formed by a drill and during the presence therein of a fluid for drilling, which borehole has a central axis and which method includes the steps of:
(a) forming with a first electromagnetic energy transmitting antenna, a changing primary magnetic field in said formation having a directional null; and (b) locating a second antenna to detect the magnetic energy resulting from the current induced in said formation, at a position relative to said directional null at which said magnetic energy is distinguishable from said primary magnetic field.
(a) forming with a first electromagnetic energy transmitting antenna, a changing primary magnetic field in said formation having a directional null; and (b) locating a second antenna to detect the magnetic energy resulting from the current induced in said formation, at a position relative to said directional null at which said magnetic energy is distinguishable from said primary magnetic field.
15. The method of claim 4 wherein said step of locating includes locating said second antenna relative to said directional null to be decoupled from said primary electromagnetic field.
16. The method of claim 14 further including the step of supporting said at least one of said antennas within a groove on the exterior surface of a cylindrical electrically conductive support structure disposed within said borehole.
17. The method of claim 14 or of claim 16 wherein said step of locating further includes locating both of said antennas within said borehole.
18. The method of claim 14 wherein said step of locating includes locating a pair of detecting antennas at opposed positions relative to said central axis.
19. The method of claim 14 wherein said step of locating includes locating at least one of said antennas at opposed positions relative to said central axis.
20. The method of claim 14 wherein said step of forming said changing magnetic field includes forming a magnetic field within said formation having a plurality of directional nulls, and said step of locating includes locating each of a plurality of said second detecting antennas at a position selected relative to a corresponding null at which said magnetic energy is distinguishable from said primary magnetic field.
21. The method of claim 20 wherein said step of locating said second detecting antennas includes locating the same symmetrically relative to said transmitting antenna in the direction of said central axis.
22. The method of claim 14 wherein said step of locating includes locating a plurality of said second antennas at differing distances from said transmitting antenna.
23. The method of claim 14 wherein said step of locating includes locating said detecting antenna radially off-set from said central axis.
24. The method of claim 23 wherein said step of locating includes placing both of said detectors at positions which are radially off-set from said central axis.
25. The method of claim 14 wherein said first transmitting antenna is radially off-set from said central axis, and further including the step of measuring the different values of current induced within said formation at respectively differing circumferential positions relative to said central axis.
26. The method of claim 14 wherein said step of locating said second antenna to detect the magnetic energy from the current induced in said formation includes adding at least one constant characteristic of a signal to current induced in said second antenna to compensate for signal characteristics caused in said second antenna by said primary magnetic field.
27. In apparatus for measuring the resistivity of a formation surrounding a borehole having a central axis, the combination comprising:
(a) a first antenna for electromagnetic energy reactive with said formation;
(b) supporting structure for said antenna to be placed in said borehole, which structure has a main axis meant to be generally coincident with said borehole central axis when said structure is in said borehole; and (c) the location of said first antenna relative to said support structure being radially off-set from said main axis.
(a) a first antenna for electromagnetic energy reactive with said formation;
(b) supporting structure for said antenna to be placed in said borehole, which structure has a main axis meant to be generally coincident with said borehole central axis when said structure is in said borehole; and (c) the location of said first antenna relative to said support structure being radially off-set from said main axis.
28. The apparatus of claim 27 wherein said first antenna transmits a changing magnetic energy to induce an electrical current within said formation, and further including means circumferentially off-set from said transmitting axis for measuring from said borehole the differing values of current induced within said formation at respectively differing distances.
29. The apparatus of claim 28 wherein said current measuring means comprises a plurality of electrodes supported within said borehole by said supporting structure at differing distances from said main axis.
30. The apparatus of claim 27 wherein said support structure is generally cylindrical and said first antenna is positioned in a groove on the exterior surface thereof.
31. The apparatus of claim 27 wherein said first antenna is elongated and positioned on said support structure generally parallel to said main axis.
32. The apparatus of claim 31 wherein said first antenna includes a core of magnetic material surrounded by a coil of electrically conductive material.
33. The apparatus of claim 27 wherein said support structure is electromagnetic and there also is a second antenna that is part of said combination, one of said antennas being an antenna for transmitting changing magnetic energy into said formation to form a primary magnetic field having a directional null therein and induce an electrical current in said structure, and the other of said antennas being a detecting antenna for detecting the secondary magnetic field resulting from the electrical current induced in said formation by said primary field, positioned at a location relative to said null at which said secondary magnetic field is distinguishable from said primary magnetic field.
34. The apparatus of claim 33 wherein said detecting antenna is located relative to said null to be generally decoupled from said primary magnetic field.
35. In a method of measuring the resistivity of a formation surrounding a borehole at the time the borehole is being formed by a drill and during the presence therein of a conductive cooling fluid for drilling, which borehole has a central axis and which method includes the steps of:
(a) generating a changing magnetic field in said formation with a first transmitting antenna;
(b) detecting with a second antenna the magnetic energy resulting from the electrical current induced in said formation; and (c) locating at least one of said antennas within said borehole radially off-set from said central axis.
(a) generating a changing magnetic field in said formation with a first transmitting antenna;
(b) detecting with a second antenna the magnetic energy resulting from the electrical current induced in said formation; and (c) locating at least one of said antennas within said borehole radially off-set from said central axis.
36. The method of claim 35 wherein said first transmitting antenna is radially off-set from said central axis and further including the step of measuring the different values of current induced within said formation at respectively differing radial positions relative to said central axis.
37. The method of claim 35 further including the step of supporting at least one of said antennas within a groove on the exterior surface of a cylindrical magnetically conductive support structure disposed within said borehole.
38. The method of claim 35 wherein said step of generating a changing magnetic field in said formation includes generating a changing magnetic field in said formation having a directional null therein, and said step of locating at least one of said antennas radially off-set from said central axis includes locating the same at a position relative to said null at which said magnetic energy is distinguishable from magnetic energy of said changing magnetic field.
39. The method of claim 38 wherein said step of locating further includes positioning said antenna at a location relative to said null at which it will be generally decoupled from said changing magnetic field.
40. In apparatus for measuring the resistivity of a formation surrounding a borehole having a central axis, the combination comprising:
(a) a first antenna for electromagnetic energy interactive with said formation;
(b) supporting structure for said antenna to be placed in said borehole, which structure has a main axis meant to be generally coincident with said borehole central axis when said structure is in said borehole; and (c) said first antenna including a central core of ferromagnetic material surrounded by an electrically conductive coil.
(a) a first antenna for electromagnetic energy interactive with said formation;
(b) supporting structure for said antenna to be placed in said borehole, which structure has a main axis meant to be generally coincident with said borehole central axis when said structure is in said borehole; and (c) said first antenna including a central core of ferromagnetic material surrounded by an electrically conductive coil.
41. In apparatus for measuring the resistivity of a formation surrounding a borehole having a central axis, the combination comprising:
(a) means for forming a changing primary magnetic field having a directional null within said formation;
(b) a detecting antenna for detecting the secondary magnetic field resulting from the electrical current induced in said formation, which antenna is positioned at a location relative to said null at which said secondary magnetic field is distinguishable from said primary magnetic field; and (c) means connected to said detecting antenna responsive to electricala current induced therein upon the detection of said secondary magnetic field, which means includes a controller for adding constant characteristics of a signal to said induced current to compensate for signal characteristics caused by said primary magnetic field.
(a) means for forming a changing primary magnetic field having a directional null within said formation;
(b) a detecting antenna for detecting the secondary magnetic field resulting from the electrical current induced in said formation, which antenna is positioned at a location relative to said null at which said secondary magnetic field is distinguishable from said primary magnetic field; and (c) means connected to said detecting antenna responsive to electricala current induced therein upon the detection of said secondary magnetic field, which means includes a controller for adding constant characteristics of a signal to said induced current to compensate for signal characteristics caused by said primary magnetic field.
42. In apparatus for measuring the resistivity of a formation surrounding a borehole having a central axis, the combination comprising:
(a) means for creating an electric field in said formation;
(b) electrically conductive supporting structure to be placed in said borehole, which structure has a main axis meant to be generally coincident with said borehole central axis when said structure is in said borehole; and (c) a plurality of current detectors carried on said electrically conductive supporting structure in insulated relationship thereto, each of said detectors being positioned to detect the value of current going thereto from said formation, which detectors are respectively at differing circumferential positions relative to said main axis whereby each detects a different value of current.
(a) means for creating an electric field in said formation;
(b) electrically conductive supporting structure to be placed in said borehole, which structure has a main axis meant to be generally coincident with said borehole central axis when said structure is in said borehole; and (c) a plurality of current detectors carried on said electrically conductive supporting structure in insulated relationship thereto, each of said detectors being positioned to detect the value of current going thereto from said formation, which detectors are respectively at differing circumferential positions relative to said main axis whereby each detects a different value of current.
43. The apparatus of claim 42 wherein said supporting structure is also magnetically conductive and said means is a first antenna supported by structure for forming a changing primary magnetic field in said formation.
44. The apparatus of claim 43 wherein said first antenna forms a changing magnetic field having a directional null and further including a second detecting antenna for detecting the secondary magnetic field resulting from the electric field created in said formation, which second antenna is positioned at a location relative to said null at which said secondary magnetic field is distinguishable from said primary magnetic field.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US581,561 | 1990-09-10 | ||
| US07/581,561 US5089779A (en) | 1990-09-10 | 1990-09-10 | Method and apparatus for measuring strata resistivity adjacent a borehole |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2050953A1 true CA2050953A1 (en) | 1992-03-11 |
Family
ID=24325672
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002050953A Abandoned CA2050953A1 (en) | 1990-09-10 | 1991-09-09 | Conductivity log for boreholes |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US5089779A (en) |
| EP (1) | EP0475715A3 (en) |
| JP (1) | JPH04233491A (en) |
| CA (1) | CA2050953A1 (en) |
| NO (1) | NO913539L (en) |
Families Citing this family (47)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5337002A (en) * | 1991-03-01 | 1994-08-09 | Mercer John E | Locator device for continuously locating a dipole magnetic field transmitter and its method of operation |
| US6002258A (en) * | 1991-03-01 | 1999-12-14 | Digital Control, Inc. | Method for locating a boring tool |
| US6417666B1 (en) * | 1991-03-01 | 2002-07-09 | Digital Control, Inc. | Boring tool tracking system and method using magnetic locating signal and wire-in-pipe data |
| US6008651A (en) * | 1991-03-01 | 1999-12-28 | Digital Control, Inc. | Orientation sensor arrangement and method for use in a system for monitoring the orientation of an underground boring tool |
| US5491488A (en) * | 1992-06-11 | 1996-02-13 | Baker Hughes Incorporated | Electromagnetic propagation tool using magnetic dipole antennas |
| US5467019A (en) * | 1994-03-01 | 1995-11-14 | Western Atlas International Inc. | Method and apparatus for balancing the electrical output of the receiver coils of an induction logging tool by use of a slidable magnetic rod for eliminating direct coupling |
| GB9404381D0 (en) * | 1994-03-07 | 1994-04-20 | Bpb Industries Plc | Induction logging instrument |
| NO314646B1 (en) * | 1994-08-15 | 2003-04-22 | Western Atlas Int Inc | Transient electromagnetic measuring tool and method for use in a well |
| US6035951A (en) * | 1997-04-16 | 2000-03-14 | Digital Control Incorporated | System for tracking and/or guiding an underground boring tool |
| US6100696A (en) * | 1998-01-09 | 2000-08-08 | Sinclair; Paul L. | Method and apparatus for directional measurement of subsurface electrical properties |
| US7659722B2 (en) | 1999-01-28 | 2010-02-09 | Halliburton Energy Services, Inc. | Method for azimuthal resistivity measurement and bed boundary detection |
| US6163155A (en) * | 1999-01-28 | 2000-12-19 | Dresser Industries, Inc. | Electromagnetic wave resistivity tool having a tilted antenna for determining the horizontal and vertical resistivities and relative dip angle in anisotropic earth formations |
| GB9916576D0 (en) * | 1999-07-15 | 1999-09-15 | Geolink Uk Limited | A directional instrument |
| US6496008B1 (en) | 2000-08-17 | 2002-12-17 | Digital Control Incorporated | Flux plane locating in an underground drilling system |
| US6703837B1 (en) * | 2000-09-15 | 2004-03-09 | Precision Drilling Technology Services Group, Inc. | Wellbore resistivity tool with simultaneous multiple frequencies |
| US7098858B2 (en) * | 2002-09-25 | 2006-08-29 | Halliburton Energy Services, Inc. | Ruggedized multi-layer printed circuit board based downhole antenna |
| US7345487B2 (en) * | 2002-09-25 | 2008-03-18 | Halliburton Energy Services, Inc. | Method and system of controlling drilling direction using directionally sensitive resistivity readings |
| US7080699B2 (en) * | 2004-01-29 | 2006-07-25 | Schlumberger Technology Corporation | Wellbore communication system |
| US7327145B2 (en) | 2004-03-01 | 2008-02-05 | Pathfinder Energy Services, Inc. | Azimuthally focused electromagnetic measurement tool |
| US7385400B2 (en) | 2004-03-01 | 2008-06-10 | Pathfinder Energy Services, Inc. | Azimuthally sensitive receiver array for an electromagnetic measurement tool |
| CA2584068C (en) * | 2004-10-22 | 2011-05-10 | Baker Hughes Incorporated | Magnetic measurements while rotating |
| RU2394270C1 (en) | 2006-07-11 | 2010-07-10 | Хэллибертон Энерджи Сервисиз, Инк. | Modular instrument unit for geo-control |
| BRPI0713267B1 (en) * | 2006-07-12 | 2018-06-19 | Halliburton Energy Services, Inc. | “METHOD FOR BUILDING AN INCLINED ANTENNA ON A RECOVERABLE SEGMENT OF A RECORDING DRILLING TOOL, A RECOVERABLE DOWN DRILLING TOOL” |
| US8593147B2 (en) | 2006-08-08 | 2013-11-26 | Halliburton Energy Services, Inc. | Resistivity logging with reduced dip artifacts |
| US7663372B2 (en) * | 2006-09-25 | 2010-02-16 | Baker Hughes Incorporated | Resistivity tools with collocated antennas |
| CN101460698B (en) | 2006-12-15 | 2013-01-02 | 哈里伯顿能源服务公司 | Antenna coupling component measurement tool having rotating antenna configuration |
| US8436618B2 (en) * | 2007-02-19 | 2013-05-07 | Schlumberger Technology Corporation | Magnetic field deflector in an induction resistivity tool |
| US20090230969A1 (en) * | 2007-02-19 | 2009-09-17 | Hall David R | Downhole Acoustic Receiver with Canceling Element |
| US8395388B2 (en) * | 2007-02-19 | 2013-03-12 | Schlumberger Technology Corporation | Circumferentially spaced magnetic field generating devices |
| US7598742B2 (en) | 2007-04-27 | 2009-10-06 | Snyder Jr Harold L | Externally guided and directed field induction resistivity tool |
| US7898259B2 (en) * | 2007-02-19 | 2011-03-01 | Schlumberger Technology Corporation | Downhole induction resistivity tool |
| US8198898B2 (en) * | 2007-02-19 | 2012-06-12 | Schlumberger Technology Corporation | Downhole removable cage with circumferentially disposed instruments |
| WO2008115229A1 (en) * | 2007-03-16 | 2008-09-25 | Halliburton Energy Services, Inc. | Robust inversion systems and methods for azimuthally sensitive resistivity logging tools |
| US7541813B2 (en) * | 2007-04-27 | 2009-06-02 | Snyder Jr Harold L | Externally guided and directed halbach array field induction resistivity tool |
| US7583085B2 (en) * | 2007-04-27 | 2009-09-01 | Hall David R | Downhole sensor assembly |
| US20090108845A1 (en) * | 2007-10-29 | 2009-04-30 | Michael Kaminski | System for seismic detection and analysis |
| WO2010068397A2 (en) * | 2008-12-10 | 2010-06-17 | Schlumberger Canada Limited | Method and apparatus for directional well logging |
| AU2008365630B2 (en) | 2008-12-16 | 2012-05-03 | Halliburton Energy Services, Inc. | Azimuthal at-bit resistivity and geosteering methods and systems |
| GB2486759B (en) | 2010-01-22 | 2014-09-03 | Halliburton Energy Serv Inc | Method and apparatus for resistivity measurements |
| US20110227578A1 (en) | 2010-03-19 | 2011-09-22 | Hall David R | Induction Resistivity Tool that Generates Directed Induced Fields |
| WO2012102705A1 (en) * | 2011-01-25 | 2012-08-02 | Halliburton Energy Services, Inc. | Apparatus and method for making induction measurements |
| US9075164B2 (en) | 2012-05-02 | 2015-07-07 | Baker Hughes Incorporated | Apparatus and method for deep transient resistivity measurement |
| AU2012383577B2 (en) | 2012-06-25 | 2015-07-09 | Halliburton Energy Services, Inc. | Tilted antenna logging systems and methods yielding robust measurement signals |
| US9310511B2 (en) | 2012-11-01 | 2016-04-12 | Baker Hughes Incorporated | Apparatus and method for deep transient resistivity measurement |
| US9354347B2 (en) | 2012-12-13 | 2016-05-31 | Baker Hughes Incorporated | Method and apparatus for deep transient resistivity measurement while drilling |
| WO2019203791A1 (en) | 2018-04-16 | 2019-10-24 | Halliburton Energy Services, Inc. | Deconvolution-based enhancement of apparent resistivity and bed boundary identification in borehole resistivity imaging |
| CN117231212B (en) * | 2023-11-16 | 2024-02-13 | 齐鲁工业大学(山东省科学院) | Direction-while-drilling electromagnetic wave logging instrument and magnetic field direction adjusting method |
Family Cites Families (24)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2919396A (en) * | 1959-12-29 | Apparatus for electromagnetic induction surveying | ||
| US2963640A (en) * | 1957-03-04 | 1960-12-06 | Welex Inc | Well bore resistivity scanning system |
| US3383586A (en) * | 1963-11-12 | 1968-05-14 | Mobil Oil Corp | Power supply including non-conductive mechanical transmission means for radio frequency exploration unit |
| US3493850A (en) * | 1964-01-20 | 1970-02-03 | Schlumberger Technology Corp | Apparatus for investigating formations surrounding a borehole including means for generating opposite polarity current flow on opposite sides of the borehole |
| US3406359A (en) * | 1965-12-15 | 1968-10-15 | Schlumberger Technology Corp | Methods and apparatus for computing a function of sampled well logging measurements derived from multiple investigating devices |
| US3388325A (en) * | 1966-02-23 | 1968-06-11 | Schlumberger Well Surv Corp | Apparatus for supplying an equal potential to circumferential portions of a circumferentially extending electrode |
| US3539911A (en) * | 1968-06-21 | 1970-11-10 | Dresser Ind | Induction well logging apparatus having investigative field of asymmetric sensitivity |
| US3748573A (en) * | 1971-06-21 | 1973-07-24 | Shell Oil Co | Electrical logging system for use with a drill string |
| US4061967A (en) * | 1977-01-03 | 1977-12-06 | Hughes Tool Company | Support system for rotatable detecting element |
| US4609873A (en) * | 1980-01-04 | 1986-09-02 | Texaco Inc. | Dielectric well logging system with at least three transmitter coils and at least two receiver coils for determining resistivity and dielectric constant of a subsurface formation adjacent a fluid invaded zone of the formation |
| US4725837A (en) * | 1981-01-30 | 1988-02-16 | Tele-Drill, Inc. | Toroidal coupled telemetry apparatus |
| US4348672A (en) * | 1981-03-04 | 1982-09-07 | Tele-Drill, Inc. | Insulated drill collar gap sub assembly for a toroidal coupled telemetry system |
| US4387372A (en) * | 1981-03-19 | 1983-06-07 | Tele-Drill, Inc. | Point gap assembly for a toroidal coupled telemetry system |
| US4451789A (en) * | 1981-09-28 | 1984-05-29 | Nl Industries, Inc. | Logging tool and method for measuring resistivity of different radial zones at a common depth of measurement |
| US4525715A (en) * | 1981-11-25 | 1985-06-25 | Tele-Drill, Inc. | Toroidal coupled telemetry apparatus |
| DE3308559C2 (en) * | 1983-03-08 | 1985-03-07 | Prakla-Seismos Gmbh, 3000 Hannover | Borehole measuring device |
| US4785247A (en) * | 1983-06-27 | 1988-11-15 | Nl Industries, Inc. | Drill stem logging with electromagnetic waves and electrostatically-shielded and inductively-coupled transmitter and receiver elements |
| US4651101A (en) * | 1984-02-27 | 1987-03-17 | Schlumberger Technology Corporation | Induction logging sonde with metallic support |
| GB2156527A (en) * | 1984-03-30 | 1985-10-09 | Nl Industries Inc | Aperture antenna system for measurement of formation parameters |
| US4712070A (en) * | 1984-05-31 | 1987-12-08 | Schlumberger Technology Corporation | Apparatus for microinductive investigation of earth formations |
| US4716973A (en) * | 1985-06-14 | 1988-01-05 | Teleco Oilfield Services Inc. | Method for evaluation of formation invasion and formation permeability |
| US4786874A (en) * | 1986-08-20 | 1988-11-22 | Teleco Oilfield Services Inc. | Resistivity sensor for generating asymmetrical current field and method of using the same |
| US4933640A (en) * | 1988-12-30 | 1990-06-12 | Vector Magnetics | Apparatus for locating an elongated conductive body by electromagnetic measurement while drilling |
| US4980643A (en) * | 1989-09-28 | 1990-12-25 | Halliburton Logging Services, Inc. | Induction logging and apparatus utilizing skew signal measurements in dipping beds |
-
1990
- 1990-09-10 US US07/581,561 patent/US5089779A/en not_active Expired - Fee Related
-
1991
- 1991-09-09 CA CA002050953A patent/CA2050953A1/en not_active Abandoned
- 1991-09-09 NO NO91913539A patent/NO913539L/en unknown
- 1991-09-10 EP EP19910308233 patent/EP0475715A3/en not_active Withdrawn
- 1991-09-10 JP JP3230510A patent/JPH04233491A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| EP0475715A2 (en) | 1992-03-18 |
| NO913539L (en) | 1992-03-11 |
| EP0475715A3 (en) | 1993-05-05 |
| NO913539D0 (en) | 1991-09-09 |
| US5089779A (en) | 1992-02-18 |
| JPH04233491A (en) | 1992-08-21 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA2050953A1 (en) | Conductivity log for boreholes | |
| CA2395515C (en) | An apparatus accurately measuring properties of a formation | |
| US10677043B2 (en) | External hollow antenna | |
| CA2485254C (en) | Induction measurements with reduced borehole effects | |
| US7888940B2 (en) | Induction resistivity cover | |
| CA2345567C (en) | A permanently emplaced electromagnetic system and method for measuring formation resistivity adjacent to and between wells | |
| EP1597610B1 (en) | Measuring equipment and method for mapping the geology in an underground formation | |
| CA2458395C (en) | Integrated borehole system for reservoir detection and monitoring | |
| US7345487B2 (en) | Method and system of controlling drilling direction using directionally sensitive resistivity readings | |
| US8400159B2 (en) | Casing correction in non-magnetic casing by the measurement of the impedance of a transmitter or receiver | |
| US8436618B2 (en) | Magnetic field deflector in an induction resistivity tool | |
| CA2521456C (en) | Method and apparatus for measuring mud resistivity | |
| CN101932955A (en) | Look ahead logging system | |
| US20050242819A1 (en) | Compact magnetic sensor for multi-component induction and micro-resistivity measurements | |
| US20110227578A1 (en) | Induction Resistivity Tool that Generates Directed Induced Fields | |
| EP2203764A2 (en) | Determining correction factors representing effects of different portions of a lining structure | |
| CA2595289A1 (en) | Subsurface imagery for temperature measurement and fluid flow for oil recovery using electromagnetic impedance tomography (emit) | |
| MXPA05007412A (en) | Apparatus and system for well placement and reservoir characterization. | |
| WO2010107685A1 (en) | Induction coil impedance modeling using equivalent circuit parameters | |
| EP1970733B1 (en) | An apparatus and method for electrically investigating borehole | |
| US20100295547A1 (en) | Downhole Resistivity Receiver with Canceling Element | |
| GB2382143A (en) | A method for telemetering data between wellbores | |
| US10227868B2 (en) | Electromagnetic telemetry using capacitive surface electrodes | |
| US20160259081A1 (en) | Electromagnetic formation evaluation tool apparatus and method | |
| WO2017074346A1 (en) | Inductive cavity sensors for resistivity tools |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |