CA1322151C - Device for expanding pipes - Google Patents

Abstract

ABSTRACT
The device is intended for expanding profile pipes set in a well for patching off a troublesome zone, and also for straightening crumpled casings.
The device comprises a housing having an expanding member mounted thereon in bearings on a journal exten-ding at an acute angle to the longitudinal axis of the housing. The expanding member is shaped as a spherical segment having its external surface defined by alterna-ting portions of a spherical surface and the lateral surfaces of cylinders whose geometric axes belong to a plane perpendicular to the axis of the journal.

Description

1 3221~1 The present invention relates to well-drilling technologies, and more particularly it relates to a device for expandiny pipes.

The invention can be employed to the utmost effect for expanding profile pipes used for patching off troublesome ~ones in a well-drilling operation, such troublesome zones being those associated with intsnse losses of the drilling mud and cement slurries, the inflow of either liquid or gas into the borehole from exposed formations, or caving-in of the rock being drilled.

It is not unfreguent nowadays that in the drilling of d~ep wells for oil or gag production there are encountered ~ormations which are incompatible from the drilling viewpoint, eOg. having a~normally high and low formation pressures, and also formations with the rock displaying a tendency towards crumbling or caving-in into the borehole.

The hitherto used pra~tice has been tn close off such formations by running into the well additional intermediate ~:
or curtailed casing strings. However, this practice involves considerable material inputs and costs incurred by the necessity of cementing the strings in the well and the need for additional metal, cement and operation time.
Furthermore, with every additional casing string set, the diameter of the well becomes smaller, which adversely affects the production conditions.

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A~ present, in ord~ tD provide ~Dr further dril-ling without reducing the predetermined diameter of the well, a porbion of the well in the zDne of an e~posed troubla~Dme ~DrmatlDn has a patcher set therein~ ~g.
in the form Df a atrin~ of profile pipes urged into engagement with bhe walls D~ the expanded por~ion Df the well by building up fluid pressure inside them, followed ~y calibration Df their internal passage bD
the predetermined well diam0ter by mean~ Df a pipe expan-ding device.
~ herc is know~ a devic3 for e~panding ca~ing tSU,A73n340) cDmprising a hDusing rigidly connected with a tapering guide member with slots receiving therein the expanding membars in the for~ o~ cylindrical rollers. ~he slots ex~end at an angle to bhe axis of the hDu~ing, their lDwermDst part being offset with reapec~ tD the upper-most part ln~the intended rotation direction ~f the device.
~ his known device i9 run on the drill pipe string intD the well to face a crumpled pDrtion of the casing string, and then rotated under a preset load~ so tha~
the rollers rDll in en~agement with t~e crumpled portiDn Df the casing st~ing, straightening it.
A drawback of this known device is its inadequate performanc~ reliabiliby9 as ths rollers received in the slots of thà tapering guide member D~ the 'r sing are exp~sed bD tha hazard Df bard particlas s~spended in the b~rehole ~luid findlng thalr wa~ in~o the slDts~

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causing jamming of the rollers, and ~ith some of such particles being abrasive, their rapid wearO
An~ther shortcoming of the known device i~ bhe relativel~ low axpansiDn rate imposed by th~ gr~ab frictiDn fDxces expsrienced by bhe rollers in the slobs oP the tapering guide member of bhe housing.
There i~ further known a device for expanding w011 casings upon their crumpling in a well ~SU,A,467994) comprising a hDusing in ~he ~orm D~ a dir~ck tapering guide member made in~egral with an inverse tapering guide member, the guide members having 910t5 r~ceiving therein with the aid of bearing maans the expanding members in the form o~ tapering roll~rs set at an angle to the geomat.ric longitudinal axi~ Df the housing and having their greatsr ends facing tha centre of the housing.
The last-described de~ice is operated similarly t D the previDusly described DneO
A major drawback o~ this device is the inadequate strength o~ the bearing means of its rollers, which prDhibit~ the application to the device of a su~ficiently heavy lDad9 eOg. Df a magnitude required fDr expanding profile pip~s, which adversely affects the efficiency D~ eXp~SiDtl Df pipes Df thi8 kind.
Another shDrtcoming of this last~described known d~vice i~ its lnadequa~e perform~nce reli3bilit~, on account o~ the hazard D~ suspendsd particles vf the bDre-- . ..... . .

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hole fluid, some of them abrasive, getting into the slots, threatening jamming of the rollers in the slots and their rapid wear.

Still another shortcoming of the Xnown device is its xelatively low efficiency on account of the great friction forces experienced by the rollers in the slots of the tapering guide memhers, particularly, at moments when they become 3ammed in the slots of the guide members.
There is known yet another device for expanding pipes (SU,A, 39~133) comprisiny a housing and an expanding member mounted in bearings on a j ournal at an angle with respect to the longitudinal geometric axis of the housing.
This devic~ of the prior art, however, is of a complicated structure and of inadequate efficiency on account o~ the great friction forces in the working zcne, which cuts down the effort transmitted from the expanding member to the pipe, so that this deuice of the prior art is suitable only for expanding the end portions of profile pipes.

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In one aspect, the invention provides a device for expanding pipes, comprising a housing having an expanding member mounted thereon in bearings on a journal at an angle with respect to the longitudinal axis of the housing, in which device, in accordance with the present invention, the expanding member is shaped as a spherical segment having its external surface defined by alternating portions of a spherical surface and the lateral surfaces o~ cylinders whose :~
geometric axes belong to a plane perpendicular to the axis of the journal~

Owing to the disclosed streamlined shape of the working surface of the expanding member, the device in accordance with the present invention provides for reducing significantly the friction in the zone of its engagement with the pipe being worked upon, and also for stepping up considerably the effort transmitted to this pipe, thus substantially enhancing the quality of the expanding operation and stepping up its rate.
The present invention will be made more apparent in the following description of its preferred embodiment, with xeference being made to the accompanying drawings, whereino FIG. 1 is a general view of a device embodying the present invention in the operation of expanding a profile pipe in a well;
FIG. 2 shows the device of FIG. 1, with the expanding member shown in a sectional view;

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FIG. 3 is a ~iew taken along arrow line A in ~IG. 1;
FIG. 4 is a ssctional view taken Dn line IV-IV of FIG~ 2; and FIG. 5 i~ a sectiDnal view taken Dn lins V-V of FIG. 2.
The device fDr expandin~ pipes~ embDdying the pra-sent inventiDn, cDmprise~ a~-hDu~ing 1 (FIG. 1) with a Durnal 2 (FIGo 2) having an expanding member 3 mDunted there~n ~or rDtatiDn~ ~he juurnal 2 exbends at an acute angle to the IDngitudin~l geometric axis D~ the hDusing 1, the expanding member 3 bei~g mDunted Dn the journal 2 with the aid of ball bearings 4 and 5J To inject lubri-cating grease intD the bearings 4 and 5, the expandi~g member has an Dpening 6 cl~Dseable with a screw 7~ A
sealing element 8 seals o~f the area Df engagement Df the journal 2 wlth the expanding memb~r 3~
~ he e~pandlng ~ember 3 is shaped as a spherical segmsnt 9 whose Duter working surface i9 defined by alternating portiDns 10 D~ a sp`nerical sur~ac~ ~see FIGS 1 and 3) and t~e lateral sur~aces o~ cylinders 11 whos~ respecti~e geDmetric axes 12 belong to a plane pQrp~ndicular to the longitudinal geometric agis 13 D* ~hs jDurnal 2 (i~e. extend at right angles with this axis ~3) and include ~he centre "0" D~ the sphsre de~i-ning the spherical segment 9. The cDmmDn point 14 (FIG,3) ~ inter~sctiDn of the lateral surfaces of the respective ~3221~1 cylinders 11 i9 at ~he apex of the expanding member 3.
~ he cxpanding member 3 may be in several modified vexsiDns ~nDt shDwn), e.g. with the axes 12 being sDme-what o~fset from the axis 13 of ~he expanding member 3 (iOe. Df its journal 2) in a plane normal tD this axis 13;
or else with the plane including the axes 12 being shi~ted belDw bhe cerltre "O" of the e~panding member 3;
or els~ wi~h the cylindrical surfaces 11 being substit-utcd by concave (hyperbDlic) sur~aces of revDlution.
The devics is operated, as follDws~
With profile pipes 15 having been run intD the bore-hole~ or elsc into a casing string 16 (as shDwn in ~IG. 1) ~Dr patching off a troublesome zDneS and with the pipes 15 having been s~raightened from inside by ex-cessive fluid pressureS they still have un8~raightened cDrrugatiDns 17 (FIG. 4) left about their peripheries.
Tha disc~osed devica i9 sc~`ewed ontD the drill strin~
18 (FIGS 1 and 2) a~d run ~nto ~he borehole, or else into the casing string 16~ Owing tD the streamlined shape of its working sur~ace, the expanding member enter3 the internal space of the pro~ile ~ipes 15 and, with the drill pipe string 18 being rotated, ~traightens out the corrugation~ 17 unstraightened by the ~luid pressure, while at the same time calibrating the entire inner sur~ace o the profile pipes 15 and urging them into tight en~agcment with either the wall Df the borehola of the casing string 16, as shown in FIG. 5.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY OR
PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
A device for expanding pipes, comprising:
a housing;
a journal provided on said housing at an angle with respect to the longitudinal geometric axis thereof;
an expanding member mounted on said journal;
ball-bearing means supporting said expanding member on said journal;
said expanding member being shaped as a spherical segment having its external surface defined by alterna-ting portions of a spherical surface and the lateral surfaces of cylinders whose geometric axes belong to a plane perpendicular to the axis of said journal.