US 2809013 A
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Description (OCR text may contain errors)
oct. s, 1.957
L.. W. LEDGERWOOD, JR., ETAL APPARATUS Foa MATNTAINTNG CONSTANT WEIGHT oN A WELL Toor.
Filed Jan. 29.1952
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APPARATUS FOR MAINTAININGCONSTANT WEI'GHT 0N A WELL TOOL 3 Sheets-Sheet 2 Filed Jan. 29, 1952 ..-.-I ..--ll.-. -1-. Y a A ,f A 5 TIC-Sfil- QIF' @nA/cahors 0d 8, v1957 L. w. LEDGERwooD, JR.. ElM 2,809,013
APPARATUS FOR MAINTINING CONSTANT WEIGHT ON A WELL TOOL United States Patent() APPARATUS FOR MAINTAINING CONSTANT WEIGHT ON A WELL TOOL Leroy W. Ledgerwood, Jr. and Fredric H. Deily, Tulsa,
Okla., assignors to Esso Research and Engineering Company, a corporation of Delaware Application January 29, 1952, Serial No. 268,885 1 Claim. (Cl. 2505-24) This invention concerns a novel apparatus primarily to be employed in a string of drill'pipej in order toV insure maintenance of a constant weight on a tool suspended by the drill pipe. The apparatus comprises a sliding sleeve assembly to be positioned at some point in a drill string above a tool on which it is desired to maintain a constant force. The sleeve of this invention serves to weight the tool referred to dependent on the weight of` apparatus below the sleeve element but independently of the weight or amount of drill string which may be employed above the sliding sleeve arrangement. It is a particular feature of this apparatus that means are provided for giving positive hydraulic information at the surface `of the earth as to the critical positioning of the sleeve element so as to avoid changes of weight on the drill tool which isemployed.
In drilling bore holes in the earth inA the search for and production of petroleum from the earth, a wide variety of tools may be suspended from a tubular string of piping ordinarily called a drill string. Thus the drill string may be employe-d to support and turn drilling apparatus, reaming apparatus, coring apparatus, logging apparatus, well cementing tools, and other types of drilling apparatus. in many cases .it becomes desirable to force the apparatus against the bottom of thebore hole with a constant force and in some cases to provide little force on the tool at the bottom of the bore hole. It is the purpose of this invention to provide apparatus which will permit maintaining a constant force on a tool suspended from a drill string independent of the length of the drill string and the weight of the drill'string. The invention is particularly desirable in providing means to maintain a minimum downward Vforce onthe tool employed.
The present invention is of particular application to a type of drilling which has been called pellet impact drilling. Employing this `drilling technique, a jet nozzle is employed to direct and propel a stream of high velocity pellets against the bottom of a bore hole to secure drilling action; ln the simplest form of pellet impact drilling apparatus, it becomes desirable to space the jet nozzle assembly at'a fixed distance froml the bottom of the. bore hole without permitting direct contact of any portion of the pellet impact drilling tool. In another form of drill bit 'used in pellet impact drilling, a mechanicalV standoi arrangement may `be used to maintain the nozzles associated therewith at a fixed distance from the bottom of the bore hole. Some weight may be tolerated and preferably is employed to maintain the standolf arrangement in Contact with the bottom of the bore hole at all times. However, it is desirable that the weight applied to a tool of this character be small and substantially constant. The present invention provides a means for maintaining a pellet-impact drilling apparatus in close proximity but free of actual contact with the bottom of a bore hole. ,Again, the present invention provides a means,if desired, for forcing the drilling tool employedagainst. the bottom of a bore hole with a constant force. For 4purposes of `claritythe invention 2,809,013 Patented Oct. 8, 1957 ICC will be described with particular reference to the use of pellet impact drilling tools. However, it is to be understood that the invention is broadly applicable to critically maintaining desired weight on any type of tool employed in conjunction with a drill string in a bore hole. In this connection, for example, in one embodiment of this invention it is practical to use the apparatus for the purpose of maintaining a large but constant Weight on a conventional rotary drilling tool. This is particularly valuable in the drilling of deep bore holes since it becomes necessary to relieve a portion of the weight of the drill string lfrom the tool at bottom to prevent buckling and failure of the drill string.
Three different and preferred modifications of this invention are illustrated in the accompanying drawings. ln these drawings Figures 1, 4 and 5 illustrate the three embodiments of the invention in cross-sectional, elevational detail.
Figure 2 is a cross-sectional View of Figure l along the line II-II while Figure 3 is a cross sectional view of Figure l along the line IIIIII.
Figure 6 is a cross-sectional View of the apparatus of Figure 5 along the line VI-VI, the sectional elevation constituting Figure 5 being taken on the line V-V of Figure 6.
Finally, Figure 7 shows a cross-sectional, elevation view of a desirable adjunct to each of these embodiments if desired to minimize the weight applied to the drilling tool.
Referring first to Figure l, an embodiment of the invention is illustrated as applied to the critical positioning of a pellet impact drilling tool from the bottom of a bore hole. The apparatus is illustrated in operative drilling position within a bore hole 1. The numeral 2 designates a type of pellet impact drilling tool. A primary nozzle 3 is employed which is in uid communica tion with a drill .string 5. Immediately below and concentric with the primary nozzle 3 is a venturi element 4. Fluid pumped through the drill string is ejected from the primary nozzle as a high velocity directed jet of fluid which ilows downwardly through the venturi element 4. As will be described, hard, dense, spherical pellets are entrained in the jet of fluid between the primary nozzle 3 and the Venturi element 44 and directed downwardly towards the secondary nozzles 6. As illustrated, a plurality of secondary nozzles may be employed which, if desired, may have the general arrangement shown in Figure 3. The enlarged chamber 7 in the drill head 2 between Venturi element 4 and the secondary nozzles 6 performs a particular function. The diverging contiguration of this chamber transforms the kinetic energy of the jet of fluid passing through venturi element 4, into internal energy. Mixing of the pellets and fluid takes place in chamber 7, and then the fluid-pellet mixture is re-accelerated through nozzles 6. Chamber 7 is preferably elongated sufliciently to secure effective distribution of the mixed fluid and pellets to each of nozzles 6. Alternatively deflectors may be positioned in chamber 7 or the orifice size of the nozzles 6 may be adjusted to obtain the desired distribution of fluid and pellet ow. It will be observed that the secondary nozzles 6 extend through a drilling head member providing a substantially llat termination which is positioned above the bottom of the bore hole. Pellets ejected through the nozzles 6 to some extent rebound against the flat drilling head member. Again the fluid employed to propel these pellets exerts a jet reaction which combines with the action referred to so as to provide an upward component of force tending to maintain 4the drilling tool in the position shown at a spaced distance from the bottom of the bore hole. In addition, the fluid moving upward after 3 contact with bottom will exert an upward force on head 2.
The general uid ow at the bottom of the 'bone hole carries the pellets outwardly and then forces the pellets upwardly in the restricted annular channel provided between the wall of the bore hole and the periphery of the drilling member 2. Pellets carried upwardlykin this annular space may settle from the stream of drilling fluid above the upper lip of the drilling head 2 which is arranged as la sleeve member 8 to form an annular channel between the nozzle support member 9 and the sleeve 8. This separation of the pellets occurs in lange part due to the `fact that fluid above sleeve element S has =a substantially reduced upward linear flow velocity due to the enlarged annular space available for ow of uid. Again, nozzle 3 arranged as shown, creates a-n aspirating action effective to cause the circulation of pellets downwardly within the sleeve member 8 into the path of fluid ejected from nozzle 3. Consequently, the continued circulation of pellets, las described, occurs duri-ng passage of fluid through the nozzles referred to.
As brought out, in the operation of a tool of this character there are one or more components of force directed upwardly against the tool. It is the purpose of this invention to provide a practical means `for using these upward components of force to maintain the desired positioning of the tool with respect to the bottom of the bore hole. Alternatively, it may be considered that means are required to maintain a constant weight or downward force on the type of tool referred to.
ln accordance with this invention a sleeve coupling is provided between an upper portion of the drill string and a lower portion of the drill string to which the tool is attached. Thus in Figure 1 drill string 5 is provided with an internal recess acting as -a sleeve to accommodate the lower section of tubing identified by numeral 9. The upper termination of tubing 9 is permitted to slide freely within the lower sleeve termination of tubing 5. It is necessary that the sleeve connected tubings be maintained in fluid tight relationship. To accomplish this an annular packing member 10 may rbe positioned rat one or more points of contact between tubing 9 and the sleeve on tubing 5. Provision is also required to limit the extent of relative movement of the interconnected tub-ing members. Thus, in introducing or removing the tool illustrated from the bore hole, it is necessary that tubing 5 be enabled to hold and lift the lower tubing section 9 carrying the attached tool. For this purpose pins 11 may be fixed in the outer sleeve member 5 extending inwardly to lit in slots provided in the inner sleeve member 9. This arrangement is particularly illustrated i-n Figure 2. By virtue of the arrangement of pins referred to in suitable longitudinals slots in the inner tubular member 9, the pins impose denite limits of relative movement between the two interconnected tubing elements. Again, this arrangement permits transmission of rotary torque from the upper tubular element to the lower tubular element to permit the drilling operations contemplated.
It is a particular feature of this arrangement that ports 12 are arranged within the inner sleeve member 9. These ports are so positioned that when tube 9 has moved so as to approach the lower limit of movement with respect to drill string 5, the ports 12 extend below the lower edge of the sleeve element of drill string 5. A fluid passage is thus exposed so that lluid may pass through the drill string and through the ports 12 into the bore hole. Ports 12 are shaped to have suflicient open area so that when this occurs a substantial pressure drop will occur within the drill string. This condition can readily be detected at the surface of the earth to inform an operator that the drilling tool lhas approached the limit of movement with respect to the drill string 5.
In employing the Yapparatus of Figure l the drilling tool 2 Vattached as illustrated may be Ilowered to the bottom of a bore hole. Drilling uid is pumped downwardly through the drill string to permit circulation and drilling with the pellets referred to. The upward force provided by the rebounding and circulation of the pellets and fluid against the drilling head may be considered to lioat the lower portion of the apparatus at a predetermined offbottom position within the sleeve connection provided. However, as drilling proceeds, if 4drill string 5 is held at a fixed level, the lower portion of the apparatus will eventually drop until ports 12 Iare exposed. At this time the drop in hydraulic pressure within the drill string will establish the necessity of lowering the drill string 5 a distance less than the limit of movement provided by the pins described. Lowering the -drill string as required will not increase the weight on the drilling tool and this quential type of operation may be continued as required. Alternatively, if desired, in employing the apparatus described, the drill string 5 may be lowered at a constant rate, somewhat slower than the drilling rate. In this case it is only necessary to infrequently increase the lowering rate whenever ports 12 become exposed so as to cause a drop in the back pressure of the drill string.
Referring now to Figure 4, an embodiment of the invention is illustrated employing the same principles of operation but providing hydraulic information when the interconnected sleeve elements approach either limit of relative movement. Referring to Figure 4, an inner tubular member 15 is employed which may consist of or may be connected to a drill string extending to the surface of the earth on which the entire apparatus may be suspended. As illustrated, a sleeve element 16 may be maintained in close sliding relationship with the inner tubular element 15. The sleeve element 16 may Ibe attached to a drilling tool to be employed in the bore hole or may be attached to any desired length and weight of tubing suspended on the sleeve member 16 and connected at its termination to -a ldrilling tool. A number of ports 17 may be cut through the wall of tubular member 15. A
firstY set of ports 18 arranged at `a particular level on sleeve 16, are also provided which are adapted to register with ports 17 -at -a fixed position of sliding relationship between the elements 15 and 16. A second set of Vports 19 Iare also cut through sleeve member 16 which, as illustrate-d, are arranged at a displaced point along sleeve 16 above the first set of ports 18. Again, ports 19 are adapted to register with the inner ports 17 when the inner tubular member 15 is moved upwardly so that the ports 17 are at the same level as the ports 19. Packing elements 20 may be positioned around the ports 17 to maintain sleeve 16 in fluid tight relationship with tubular member 15.
In the apparatus of Figure 4 an outer sleeve member 22, fixed to and suspended from the upper tubular member 15 extends downwardly to provide shoulder elements 23 on which latches 24 of sleeve 16 may bear. Consequently in introducing or lowering this apparatus into a bore hole, sleeve 16 may slide downwardly so that lzaztches 24 will bear on shoulders 23 of the outer sleeve Projections 25 are positioned on the inner surface of the sleeve 16. These projections are adapted to limit the downward movement of tubular member 15 with respect to sleeve 16.
The operation of this apparatus is similar to that of the apparatus of Figure 1 formerly described. Assuming that drill string .15 is held at a constant level while a drilling .-tool lattached to sleeve 16 is progressing downwardly in a bore hole, sleeve 16 will gradually drop downwardly with respect to the inner tubular member 15. This will cause ports 19 to register with ports 17 in time. As a result, fluid may pass from the inside of tubular member 15 through these ports and through the multitudinous perforations Z9 provided in the outer supporting sleeve member 22. An operator at the surface of the earth will, therefore, appreciate the necessity for lowering drill Os tri'ng 15. Drill string 15 may then be lowered until ports 17 register with ports 18. At this time the pressure in the drill stem will again drop informing an operator that the lower limit of movement has been reached. Y
In order for this apparatus to operate in the most desirable manner, certain modifications are desirably included in the apparatus. It is important that the inner tubular member'1`5 extend downwardly for a substantial distance belowthe ports 18 in sleeve member 16. An annular seal member 31, which may be xed to the lower termination of tubular member 15, is employed to maintain a fluid tight seal between this member and sleeve 16. It is necessary that this packing seal 31 be positioned below ports 17, a distance greater than the distance between ports 18 and 19 which` are positioned in the sleeve member 16. Y
Effective sliding relation of tubular member l5 and sleeve 16 may be maintained by providing annular collars on tube which may be machined to close limits of tolerance within sleeve 16.
. As described, it is not necessary to retain the rotational register between the sleeve elements of this apparatus. This becomes practical by usinga sufficient number and angular arrangement of the ports intended to register so that at least one pair of ports will register regardless of the rotational relationship of tube 15 with sleeve 16. However, if this apparatus is to be employed with'a tool to be rotated in a bore hole, it is necessary to provide a slotted key-way or the equivalent between tube 15 and sleeve 16 for the transmission of torque.
Referring now to Figure 5 and Figure 6, a modiiied form of the apparatus of Figure 4 is illustrated. ln the apparatus of Figure 5 the drill string or tubular member attached thereto is designated by number 35. An outer sleeve member 36 is maintained in itted sliding relationship with tube 35. Sleeve 36 extends downwardly for attachment to a tool to be employed in the bore hole. Ports 37 are provided which pass through the wall of tube 35. Packing seals 38 are employed around these ports so as to maintain a fluid seal between these ports and the clearance passageway between sleeve 36 and tube 35. A first set of ports 39 are provided at one level in sleeve 36 and a second set of ports 40 are maintained at a different level in sleeve 36. As illustrated, in Figure 6, in this embodiment of the invention, longitudinal keyways are cut in tube 35 and sleeve 36 to accommodate the keys 48. These keys are employed to maintain a tixed rotational register between members 36 and 35 and to permit transmission of rotary torque from member 35 to sleeve 36. Again the keys 48 serve to maintain ports 37 of tube 35 in the same vertical plane as ports 39 and 40 of sleeve 36.
Latch recess 45 may be cut in an upper portion of sleeve 36. This latch recess is adapted to engage latching dogs 46 which are pivotally attached to tubular member 35. Latching dogs 46 are at all times urged outwardly by means of suitable springs. Consequently, as illustrated in the drawing, if sleeve member 36 is lowered with respect to tubular member 35, the latching dogs 46 will be forced into the recess 45. By this means tube 35 can be used to lift the entire apparatus from the bore hole. It will be observed from Figure 6 that latching dogs 46 and recess 45 are positioned on members 35 and 36 out of vertical alignment with the ports 37, 39, and 4l). Again, in the apparatus of Figure 5, a lower packing seal 38 is employed to maintain the fluid seal between the inner tubular member 35 and sleeve 36. It is necessary that this packing seal 38 be positioned below the latching dogs 46 at a distance greater than the distance between ports 39 and ports 40.
In the apparatus of both Figure 4 and Figure 5 it is possible to secure positive hydraulic information as to which of the sets of ports are exposed on movement of the innertubular member... Thus,.referring to Figure 5, for example, `the upperports 40 may be cut to have a substantially greater area than the lower ports 39. Consequently, when ports 37 register with ports 40, a substantially greaterdecrease from initial or operating pressure will occur than when ports 37 register with the ports 39. This provision enables an operator at the surface of the earth to immediately tell the relative position of tube with respect to sleeve 36.
Itshould be observed that in each of the embodiments described, the tubular and sleeve elements of the apparatus may be reversed.
It may be noted that the apparatus as described is particularly adapted for automatic lowering of a drill string while maintaining constant weight on a tool suspended in a bore hole. Thus the hydraulic indications provided by the sleeve arrangements described may be employed to operate theAhydraulic brake associated with a lowering winch. Release of hydraulic pressure caused on the sleeve arrangement reaching a limiting position may thus automatically release the brake on the winch to secure a desired lo'weringof the drill string. An arrangement of this nature is disclosed in co-pending application Ser. No. 268,883, of Leroy W. Ledgerwood, Jr., tiled January 29, 1952, now Patent No. 2,724,574.
In the use of this invention to maintain a tool displaced from the bottom of a bore hole, or in light contact therewith, it is desirable to supplement upward forces acting on` the sleeve arrangements described. For example, in positioning a jet nozzle at some distance from the bottom of a bore hole, the upward jet reaction against bottom may be aided by-a hydraulic arrangement acting on the sleeve arrangement. A suitable hydraulic arrangement for this purpose is illustrated in Figure 7.
In this drawing, the numeral 5i identities the drill string extending from the surface of the earth. Sleeve element 53 maintained in sliding relationy with drill string 5l is connected to a lower tubular member 52 which may be connected in turn to any desired drilling tool. A -cylinder 54 is fixed to and extends around drill string 5l, depending downwardly to enclose the upper portion of sleeve 53. The upper lip of sleeve 53 may be enlarged to form a piston 57 slidable within cylinder 54. A packing seal 55 is maintained at the lower termination of cylinder 54 to provide a uid seal between the cylinder and sleeve 53. A -conduit passage 56 may extend through the wall of the cylinder terminating in an orifice on the inside of cylinder 54, near the bottom thereof. This provides a uid passage between the interior of drill string 51 and the interior 0f the cylinder beneath piston 57.
In operation the apparatus functions as follows: drilling mud will be pumped down drill string 52 to supply a tool such as shown in Figure l, for example. The pressure within drill string 51 will consequently lbe higher than the pressure exterior of the drill string. As a result, drilling Huid will pass through conduit 56 into cylinder 54, providing an upward force against piston 57. A port 58 in the upper portion of the lcylinder permits this force to move the piston upwardly if this force exceeds downward force components on sleeve 53. In this way, the piston acts to provide a constant upward -force on the lower sleeve elements independently of any upward forces contributed by the tool used. The upward force contributed by the piston arrangement may critically be set by xing the area of the piston and the pressure differential maintained across the piston. A lower port 59 is provided in sleeve element 53 to provide hydraulic information of the approach to the limiting position of movement of the sleeve arrangement.
It is to be understood, as already stated, that the principal purpose lof the structure shown in Figure 7 is to supplement the upward forces that tend to maintain the jet nozzle at some distance from the bottom of the bore hole. When the pressure of the fluid in the drill pipe exceeds the pressure of the fluid in the well, which is the situation l that would obtain during drilling, an upward pressure will be exerted against piston 57. If the pressure differential i`s suficiently great tor overcome the downward forces contributed by the Weight of members Slaandl 53 and any elements depending therefrom, and by the downward pressure exerted on piston 57 'by the fluid in the bore hole, and counterbalanced by anyv upward reaction 4from the jet nozzle at the bottom of the bore hole, piston 57 would travel to the top of the cylinder. The apparatus would not be designed to bring about this result, however, since the structure of Figure 7 is intended merely to supplement the upward forces exerted on the drill nozzle. Hence the cylinder and piston arrangement should be of selected size, for the operating pressures being used and for the weight of the elements depending from. the piston, such that the upward force againstpiston S7 would not be great enough to cause piston 57 to move to the top of the cylinder by this hydraulic force alone. If this hydraulic force, plus therupward force exerted against the drill nozzle is sufiiciently great, piston 57 will tend to move upwardly. It should be entirely obvious, however, that as soon as piston 57 begins to move upwardly to any extent the jet nozzle on the drill will be lifted a greater distance from the bottom of the bore hole, which will in turn reduce the lifting effect of the jet reaction at the bottom of the bore hole. Hence piston 57 will move upwardly only to the extent necessary to bring the upward and downward forces into balance.
What is claimed is:
A coupling arrangement for a drill string and a well tool which is connected to and depending from the drill string comprising a pair of tubular members maintained inv fluid-tight telescopic sliding relationship, one of said members being iixed to the drill string, and the other of said members being fixed to the tool,means limiting the retracted and extended positional relations of the tubular members, at least one first port in a first of said tubular members, at least onel second port in the second of said tubular members, said first andsecond ports being so positioned as to register with each other when the tubular members reach a position adjacent their outermost extension from each other, at least one third port in said first tubular member spaced longitudinally from said first port, said third and said second ports being so positioned as to regi-ster with each other when said tubular members are retracted relative to each other, the total aggregate cross-sectional area of said third ports differing substantially from the total aggregate cross-sectional area of said first ports.
References Cited in the file of this patent UNITED STATES PATENTS 1,660,033 Braswell Feb. 21, 1928 1,891,328 Le Comptel et al; Dec'. 20, 1932 2,317,021 Bassinger Apr. 20, 1943 2,341,832 Verheul et al. Feb. 15, 1944 2,549,198 Hayward Apr. 17, 1951 2,586,015 Edwards Feb. 19, 1952 FOREIGN PATENTS 545,271 Great Britain Y May 18, 1942