GB2166177A

GB2166177A - Sleeve-type stabilizer

Info

Publication number: GB2166177A
Application number: GB08430030A
Authority: GB
Inventors: Allen Kent Rives; Roderick James Mcmahon
Original assignee: METAL X CORP OF TEXAS
Current assignee: METAL X CORP OF TEXAS
Priority date: 1984-10-26
Filing date: 1984-11-28
Publication date: 1986-04-30
Also published as: GB8430030D0

Abstract

A well string sleeve-type stabilizer includes an elongated tubular body (T) having first and second annular outer peripheral surfaces (6, 7) extending longitudinally from opposite ends, respectively, of the tubular body. An annular shoulder (8) is formed on the tubular body adjacent the juncture of the first and second surfaces intermediate the ends of the tubular body. Threads (9) are formed on the second surface adjacent the shoulder. Sleeve means (10) having a bore (11) with thread means (11a) at one end engage with the threads (9) on the second surface to secure the sleeve means (10) on the tubular body. The sleeve means (10) is of a larger diameter than the tubular body T and is provided with oppositely inclined and intersecting groove means (20, 21) to provide circumferentially and longitudinally dispersed surfaces (30) of varying width to maintain maximum surface contact with the well bore and to provide maximum fluid flow path as well as conducting fluid flow through and around the sleeve means in a manner to inhibit spinning or walking of the well string as the well is drilled. <IMAGE>

Description

SPECIFICATION Sleeve-type stabilizer This invention relates generally to a sleeve-type stabilizerfor use in well strings such as drill strings to assist in stabilizing the well string in the well bore.

Various sleeve-type stabilizers havve been proposed and are in use wherein longitudinal or spiral grooves areformed externally on the sleeve. The sleeve is threadedly secured on a mandrel and can be readily replaced when it is worn out.

The present invention provides an opposed spiral arrangement on a sleeve in a sleeve-type stabilizer which provides an opposed fluid flow path in the sleeve-typestabilizerto assist in inhibiting the drill string in which the stabilizer is employed from spinning out of a thermal well being drilled. The groove arrangement ofthe sleeve ofthe present invention provides a dispersed surface arrangement on the sleeve to maintain maximum surface contact with the well bore wall at all times while providing maximum fluid flow path through the outer surface of the sleeve for circulation of well bore fluids.

Fig. 1 is a side view ofthe mandrel ortubular body forming part ofthe sleeve-type stabilizer ofthe present invention; Fig. 2 is a side view ofthe sleeve with one form of the groove configuration of the present invention thereon; and Fig. 3 is a side viewofa longer sleeve.

Attention is first directed to Fig. 1 wherein the sleeve-type stabilizer of the present invention includes an elongated tubular bodyTwhich may be of any desired length such as the normal 30 foot length of a drill or well string member, or a shorter sub if desired.

Suita ble th readed mea ns at 4 at one end 4a and 5 at the other end 5a of the bodyTare provided for connecting the tubular body T in a well string for use in a well bore.

Afirst annular peripheral portion 6 extends longitudinallyfrom an end such as one end 4a ofthe body T. A second annular peripheral surface 7 extends from the other end 5a ofthetubular body T. As shown in Fig. 1, a shoulder8 is formed adjacentthejuncture ofthefirst and second annular peripheral portions 6 and 7 intermediate the ends ofthetubular memberTas illustrated in Fig. 1.The shoulder8 may be formed by an enlargement on the tubular body as shown or by having the surfaces 6 and 7 of different diameters so that theirjuncture forms the shoulder.

Suitablethreaded means as illustrate at 9 in Fig. 1 are provided on the second peripheral surface 7 adjacenttheshoulder8.Thesleevemeans 10 is provided with a longitudinal bore 11 as shown in Figs.

2 and 3 and threads 1 la are provided adjacent one end ofthe bore 11 as represented by dotted line in Figs. 2 and 3. This arrangement enables the sleeve means 10 to be slipped over and along pheripheral surface 7 and threadedly secured in position on the tubular body T against shoulder 8 as indicated by the dotted lines 5' in Fig. 1. The outer diameterofthe sleeve means 10 is greaterthan the outer diameter ofthe tubular body T, andthustheouterannularsurface l2ofsleeve means 10 projects radially beyond thetubular body T.

First groove means 20areformed in the annular surface 12 of the sleeve means 10 and the first groove means 20 is inclined at an angle in one direction relative to the longitudinal axis of the sleeve means 10 and and extends spirally about and throughout the longitudinal extent ofthe sleeve means 10. Second g roove means 21 are provided intheannularsurface 12 and are inclined in a direction opposite to the angle of inclination ofthe first groove means 20 as shown in the drawings. The second groove means 21 extends spirally about and throughout the longitudinal extent of sleeve means 10.

The first groove means 20 and second groove means 21 each include a plurality of grooves circumferentially spaced about and inclined relative to the longitudinal axis ofthe sleeve means 10 as shown in the drawings. One groove 20a of the first groove means 20 intersects one groove 21 a of the second groove means 21 to form a pair P of grooves which intersects between the ends of the annular surface 12 on sleeve means 10, one form of such intersection being more clearly demonstrated in Fig. 2 ofthe drawings as being adjacent the central portion of each first and second groove means 20,21 and which intersection is represented generally by the letters IM.

The width and depth ofthefirstand second groove means 20,21 is such that the grooves 20a and 21 a of each groove pair Pterminate attheirend portions 22 and 23 at each end ofthe sleeve means 10 whereby fluid in the well bore and around the tubular bodyT may be readily communicated into the first and second groove means 20,21 and thus through the surface 12 on sleeve means 10withoutanysubstantial restriction.

In the embodiment illustrated in Fig. 2 where the grooves 20,21 intersect only once in the sleeve means 10 as well as in the embodiment of Fig. 3 where the grooves 20,21 intersect more than once on the sleeve means 10, the angle of inclination ofthe first and second groove means 20,21 relative to each other and to the longitudinal axis of the bodyT is such that each pair P of grooves preferably intersects adjacent their end portions at each end ofthe sleeve means 10 as represented generally by the letters IE as well as adjacent the mid portion of each pair of grooves as illustrated and represented by the letters IM.This will be described more fully.Where the groove means 20, 21 intersect only one time on the sleeve means 10 as demonstrated bythe embodiment shown in Fig. 2, the intersection of the first and second groove means 20 and 21 as represented bythevertical line 26 and horizontal line 27 adjacent the mid portion of the sleeve means 10 as well as the vertical lines 28 and 29 at the intersection of the ends of adjacent pairs P of grooves of groove means 20,21 at each end ofthe sleeve means 10 demonstrates that the total lengths of intersection of the first and second groove means 20 and 21 on the sleeve means 10 relative to the total length of sleeve means 10 preferably extends over at least approximately 50% ofthetotal length of the sleeve means 10. This is also true where the sleeve means 10is longer as shown in Fig. so thatthe first and second groove means 20,21 intersect at a plurality of intervals along the longitudinal extent of sleeve means 10 as shown in Fig. 3. Thus, substantial intersection ofthefirst and second groove means 20 and 21 is provided in the sleeve means 10 to accommodate unrestricted fluid flow in the well bore as it is circulated upwardly through the enlargement E from the drilling bit on the lower end ofthe drill string to the earth's surface in a mannerwell known in the art.

However, notwithstanding the intersection ofthe oppositely inclined and intersecting first and second groove means 20, 21 over a substantial longitudinal extentof surface 12 in sleeve means 10,the angle of inclination ofthefirstandsecond groove means 20,21 and their angle of inclination is such that surfaces 1 2a ofsubstantial extent are provided in the ungrooved portionoftheannularsurface l2ofthe sleeve means 1 Oforengagementwith the well bore wall during drilling operations to assist in maintaining the drill string centered inthewell borewhileaccommodating unrestricted fluid flowtherearound. If desired, surface areas 1 2a may have hard surfacing applied thereto.

More particularly, with sleeve-type stabilizers heretofore used, where single spirals are provided thereon, the surface on the spiral may, under some circumstances, increase hole drag and may cause more erosion on the stabilisersleeve,thus requiring fre quent removal ofthe drill string from the well bore for replacement ofthe sleeve, which operation is expen siveandtimeconsuming. Further, in some types of wells such as thermal wells,the present invention tends to preventthe drill string from spinning out of the hole due to the pressures encountered.The opposed spiral arrangement of the first and second groove means 20, 21 creates an opposed flow of fluid around the stabilizersleeve of the present invention which inhibits any spiraling effect of the drill string with the present invention therein, which spiraling might otherwise be present in the prior art spiral groove stabilizers to cause the drill string to tend to spin out ofthe well bore under pressure. Also, the dual opposed spiral arrangement and intersecting fluid flow path ofthe present invention assists in inhibiting walking ofthe drill string to one side ofthewell bore which may cause the drill string to move off course during drilling operations.

In addition, the circulating fluids in the well bore create a high pressure point offluid contact in the general region represented bythe letter D at the mid-intersection ofthefirst groove means 20 and second groove means 21, and this conjunction offluid contactfurthertends to assist in centering the stabilizer ofthe present invention in thewell bore.

Any suitable number of grooves or milled slots may be employed toform the first groove means 20, and typicallytwo to four milled slots with a right-hand spiral as illustrated bythe numeral 20 representing the first groove means relative to the longitudinal axis of the sleeve means 10 may be employed. Similarly, a like number of milled slots forming the second groove means 21 and with a left-hand spiral relative to the longitudinal axis ofthe sleeve means 10 may be employed as shown.

As noted, one right-hand groove 20 ofthefirst groove means cooperates with one left-hand groove ofthe second groove means 21 to form a pair P of intersecting first and second groove means as more clearly demonstrated in Fig. 2 ofthe drawings.

Similarly, each remaining right-hand spiral groove of the groove means 20 on the sleeve means 10 intersects a left-hand groove ofthe second groove means 21 to form additional pairs P of intersecting first and second groove means on sleeve means 10. Each pair P of intersecting grooves of the first and second groove means 20, 21 is adjacent another pair P offirst and second intersecting grooves of groove means 20, 21 on the sleeve means 10.

In the embodiment illustrated in the drawings, the sleeve means 10 is of sufficient longitudinal extent so thatthe ends of each right-hand spiral groove of the first groove means 20 intersects the end of the left-hand spiral groove of the second groove means 21 ofthe next adjacent pair P as illustrated in the drawings. This intersecting arrangement ofthe pairs of grooves of each thefirstand second groove means 20, 21 forms a plurality of circumferentially spaced, generally diamond shaped portions 30 in the outer annular surface 12 between the ends ofthe sleeve means 10. Such diamond shaped portions 30 are formed between adjacent pairs P of intersecting first and second groove means 20,21.

Also, this arrangement of intersecting grooves on the sleeve means 10 forms a plurality of circum ferentially spaced, triangular surfaces 35 in the outer annular surface 12 between the ends of each adjacent pair P offirst and second groove means 20, 21 adjacent each end ofthe sleeve means 10.

Thus, although the first and second groove means 20, 21 intersect over a substantial portion of the surface 12 ofthe sleeve means 10 to provide opposed fluid conducting paths which intersect to accomplish the desired results ofthe invention, the invention also provides an outer surface arrangement by means of the surfaces 1 2a on the sleeve means 10 so thatat least some portion ofthe outerannularsurface 12 ofthe sleeve means 10 will always be positioned to contact the well bore wall to assist in maintaining the drill string properly positioned therein during drilling operations. Itwill be noted that the ungrooved surface portions 1 2a on the annularsurface 12 are dispersed about surface 12.Also, the surfaces 1 2a, by reason of the intersecting groove means 20, 21, provide a configurationforsurface portions l2awhich has substantial annularextent between its ends which impinges as it circulatesthroughthegrooves and dischargesfrom the grooves 20, 21 in the sleeve means 10. The direction of fluid flow in the plurality of grooves 20formed inthesurface 12 of the sleeve means 10 being in a direction opposite to the fluid flow in the plurality of groove means 21 tends to negate any tendency of the drill string to walk or move from one side orthe other in the well bore as may encountered where a plurality of spiraled slots is formed in a stabilizer sleeve in one direction, such as is common with the prior art.

The foregoing disclosures and description ofthe invention are illustrative and explanatory thereof, and various changed in the sizes, shape and materials as well as in the details of the illustrated construction may be made without departing from the spirit of the invention.

Claims

1. Asleeve type stabilizerfor use in a well bore including an elongated tubular body having threaded means at each end for connecting said body in a well string; a first peripheral surface extending longitudinallu of said tubular body from one end thereof and a second peripheral surface extending longitudinally of said tubular body from the other end; an annular shoulder adjacentthejuncture ofsaid first and second surfaces intermediate the ends of said tubular body; threaded surface means formed on said second surface adjacent said shoulder; sleeve means having threaded surface meansforengagingwith said threaded surface means on said second surface, said sleeve means having an outerdiametergreaterthan the outer diameter of said tubularbodyto thereby form a radially projecting annular surface for stabilizing contact with the well bore; firstgroove means in the projecting annular surface of said sleeve means inclined in one direction relative to the longitudinal axis of said sleeve and extending from one end ofthe sleeve to the other; second groove means in the projecting annular surface of said sleeve means inclined in the opposite direction relative to said first groove means; and said first and second groove means intersecting between the ends of the projecting annular surface to provide converging fluid flow paths through said projecting annular surface of said sleeve means.

2. The invention of claim 1 whereinthefirstand second groove means each has a width, depth and angle of inclination relative to the longitudial axis of said sleeve such that the intersection of said groove means in said projecting annular surface extends over at least approximately 50% ofthe total length of said sleeve means.

3. The invention of claim 1 wherein the first and second groove means each has a depth whereby fluid maybe readilycommunicatedfrom around the tubular body into the first and second groove means and through the projecting annular surface on said sleeve means.

4. The invention of claim 1 wherein the first and second groove means each has a width, depth and angle of inclination relative to the longitudinal axis of said sleeve means whereby their intersecion of said groove means between the ends of said sleeve means forms at least one generally diamond shaped portion in the annular surface between adjacent pairs of first and second groove means.

5. The invention of claim 1 whereinsaidfirst groove means comprises a plurality of grooves circumferentially spaced about said sleeve means and inclined on said sleeve means in the same direction relative to the longitudinal axis of said sleeve means and wherein the second groove means comprises a plurality of grooves circumferentially spaced about said sleeve means and inclined on said sleeve means around the tubular body into the first and second groove means and th rough the projecting annular surface on said sleeve means.

6. The invention of claim 1 whereinsaidfirst groove means comprises a plurality of right-hand grooves circumferentially spaced on said sleeve and wherein said second groove means comprises a plurality of left-hand grooves circumferentially spaced on said sleeve means.

7. The invention of claim 6 wherein said first and second groove means is arranged on said sleeve means so that each right-hand groove of the first groove means intersects a left-hand groove of the second groove means to form adjacent pairs of intersecting grooves which intersect between their ends on said sleeve means.

8. The invention of claim 7whereintheadjacent pairs of intersecting grooves form a generally diamond shaped portion on the projecting annular surface of said sleeve means between each adjacent pair of intersecting grooves whereby a plurality of circumferentially spaced generally diamond shaped portions is provided on said sleeve means.

9. The invention of claim 8 wherein the right-hand grooves of adjacent pairs intersectthe left-hand grooves of adjacent pairs adjacent the ends of said sleeve means whereby a plurality of circumferentially spaced, triangular surfaces is formed on said projecting annular surface of said sleeve means by each pair of first and second groove means adjacent each end of said sleeve means.

10. The invention of claim 9 wherein the ends of the grooves of adjacent pairs communicate with the peripheral surface portions of the tubular body on which the sleeve means is secured.

11. The inventions of claims 1,2,3,4,5 or 6 wherein said first and second groove means intersect at only one position along their lengths and between their respective end portions on said sleeve means.

12. The invention of claims 1,2,3,4,5 or6wherein saidfirstand second groove means intersectata plurality of positions.

13. The invention of claims 1,2,3,4,5 or 6wherein the angle of inclination of said first and second groove means is substantially equal and opposite on said sleeve means.

14. The invention of claim 7 wherein the adjacent pairs of intersecting grooves form a portion on the projecting annular surface which is of smallercircumferential extent adjacent the ends thereof than it is intermediate its ends.

15. A sleeve type stabilizer substantially as hereinbefore described with reference to and as illustrated in Figs. 1 and 2 or as modified in accordance with Fig. 3 ofthe accompanying drawings.