US3478826A

US3478826A - Method and apparatus for washing solids away from single or multiple tubing strings in well

Info

Publication number: US3478826A
Application number: US796433A
Authority: US
Inventors: Willard Barnes
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-02-04
Filing date: 1969-02-04
Publication date: 1969-11-18
Anticipated expiration: 1986-11-18

Description

Nov. 18, 1969 Fxled Feb 4 1969 w. BARNES 3,478,826 METHOD AND APPARATUS FOR WASHING SOLIDS AWAY FROM SINGLE OR MULTIPLE TUBING STRINGS IN WELL 3 Sheets-Sheet l flaw/7 a;

INVENTOR.

d W H W Pam wibm & AMAM A T TOR NE YS NOV. 18, 1969 w, BARNES A 3,478,826

METHOD AND APPARATUS FOR WASHING SOLIDS AWAY FROM SINGLE 0R MULTIPLE TUBING STRINGS IN WELL 3 Sheets-Sheet 2 Filed Feb. 4, 1969 W/ Nara .Barw ea INVENTOR.

Hugh lum! & Mallhwa JTTORNEYS Nov. 18. 1969 w. BARNES 3,478,826

METHOD AND APPARATUS FOR WASHING SOLIDS AWAY FROM SINGLE 0R MULTIPLE TUBING STRINGS IN WELL Filed Feb. 4. 1969 3 Sheets-Sheet F- IVENTOR Hegel mane! MAW & Mammal 90a ,4 TTOR NE YS United States Patent US. Cl. 166301 Claims ABSTRACT OF THE DISCLOSURE A wellhead workover method and apparatus for performing washing operations in a well casing to wash away solids which are around one or more tubing strings disposed in the well casing. A wash tube is removably mounted alongside the tubing string in the well casing so that washing and pulling on the tubing string may take place simultaneously.

This application is a continuation-in-part of United States patent application, Ser. No. 645,140, filed June 12, 1967 and now abandoned.

Background of the invention Oil and gas wells are usually cased and one or multiple production tubing strings are installed therein communicating the wellhead with the producing formation or formations penetrated by the well. Under normal operating conditions, petroleum fluids flow from the producing formation or formations into the casing and to the wellhead through the production tubing strings provided in the cased well. The tubing strings have a suitable packer around them and in the casing to seal oil? the easing annulus. Sometimes sand, mud and solidified materials above the packers make it diflicult, if not impossible, to pull the tubing strings from the casing. Since, sooner or later it becomes necessary to remove the tubing strings from the casing, such stuck condition is a serious problem.

Heretofore, with a single string in a well, the removal of the stuck pipe has been accomplished by removing at least a part of the free portion of the production tubing and then using a wash-over pipe to pump fluid around the stuck tubing in an attempt to dislodge and carry away the sand or other solids accumulated above the packer. With multiple strings, the problem of removal of the stuck strings has been even more severe and has required a series of relatively diflicult operations. First, using free point indicator apparatus, the stuck point of the pipes has been located, then using pipe back-off equipment, the strings were separately and alternately unthreaded at points above the stuck area and then pulled out of the well. Fishing and jarring operations were then required to try to dislodge the remaining stuck portions of the pipe strings.

Summary of the invention.

.The present invention involves the supporting and tensioning of a production tubing string or multiple tubing strings in a well casing with a washpipe alongside the tubing string or strings which may be used for circulating Washing fluid in the well casing to remove sand or other solidified material which is around the tubing string or strings above the well packer; the tubing string or strings are supported so that an upward pull or tension may be exerted thereon without removing the washpipe from the well casing and while circulating washing fluid to gradually wash out the solids and progressively lower the mice washpipe until the solids have been sufliciently loosened and/or washed up the hole to free the stuck pipe string or strings. Also, the well is kept under control during the washing and pulling steps so that the danger of a blowout is minimized with the present invention as compared to the prior art. The complete washing and pulling procedure using the present invention is accomplished without requiring a removal of the washpipe until it has been determined that the solids have been sufficiently loosened or removed from around the tubing string or strings for permitting removal thereof from the well.

Other objects and advantages of the invention will become apparent from the following description and the accompanying drawings.

Brief description of the drawing FIG. 1 is a vertical sectional view, partly in elevation, illustrating the preferred embodiment of the present invention;

FIG. 2 is a horizontal cross-sectional view taken on line 2-2 of FIG. 1;

FIG. 3 is an enlarged vertical sectional view, partly in elevation, illustrating in particular the preferred washpipe seal assembly in the open or retracted position;

FIG. 4 is a view similar to FIG. 3, but illustrating the seal assembly in the compressed or sealing position;

FIG. 5 is a vertical sectional view, partly in elevation, of a modified form of the apparatus taken on line 55 of FIG. 6, illustrating the apparatus with multiple tubing strings for dual or multiple production; and

FIG. 6 is a horizontal cross-sectional view taken on line 6-6 of FIG. 5.

Description of the preferred embodiments In the drawings, the letter S indicates generally a production tubing string or similar pipe string which is disposed in a well casing C of a well for producing oil or other fluid therethrough under normal circumstances. When sand, mud or solidified material around the production tubing string S causes it to become stuck, so that it cannot be pulled, the apparatus of the present invention is employed and the string S is displaced laterally away from the center line of the casing C to the position substantially as shown in FIG. 1 of the drawings.

For supporting such tubing string S in the casing C, a body 10 is provided which has a support assembly A therewith, as will be more fully explained. The head or body 10 is mounted in place of the conventional Christmas tree structure at the surface of a well and preferably rests upon a spool or wellhead adapter 12. The wellhead adapter or spool is secured to the upper end of the casing by any suitable means such as a coupling collar 14 of any conventional construction.

As illustrated in FIG. 1, the coupling collar 14 is made from an upper coupling section 14a and a lower coupling section 14b which are bolted together with a plurality of bolts 15, each of which as a nut 15a therewith. The lower coupling ring 14b is threaded or is otherwise secured to the well casing C. The upper coupling ring 14a is connected to the lower end of the spool or wellhead adapter 12 by threads or other attaching means.

The spool 12 may take numerous configurations, but preferably it has an inner bore substantially of the same inner diameter as the inner diameter of the well casing C and it communicates with the bore of the well casing C so that fluid may flow either inwardly or outwardly through its ports 12a and 12b during the washing action with the apparatus of this invention to remove the sand or other material with respect to the tubing string S. Suitable lengths of pipe or tubing 16, a portion of which is shown in FIG. 1, are connected in the ports 12a and 12b for controlling the inlet or the outlet of fluid with respect to the well casing C. The upper end of the spool 12 is provided with a laterally extending annular flange 120 which receives a corresponding annular flange a of the body 10. An annular resilient seal formed of rubber or'plastic is disposed between the flanges 12c and 10a and they are held in a sealed position by means of a plurality of bolts 21, each of which has a nut 22 threaded thereto. Although only two of the bolts 21 are illustrated in FIG. 1, it will be appreciated that a greater number will generally be employed for securing the flanges 10a and 120 together. Each of the bolts 21 extends through aligned openings 1% and 12d.

The supporting assembly A for the tubing string S preferably includes an annular seal which has upper and lower metal rings 25 and 26 between which is disposed a resilient seal ring 27. The lower metal ring rests upon an internal annular shoulder 10c within the bore 10a. The upper ring 25 is adapted to be moved downwardly with respect to the seal ring 27 and the lower metal ring 26 to thereby laterally compress and internally distort the seal ring 27 for more effective sealing with the external surface of the tubing string S. It is to be noted that the tubing string S preferably has a shorter length 30 or a plurality of such shorter length pipes 30 at its upper end above the upper collar 31, each length 30 being known as a pup joint. One of such pup joints 30 is actually the portion of the string S which is engaged by the seal ring 27 after the ring 25 has been moved downwardly to effect a compression of the ring 27.

For moving the ring 25 downwardly to accomplish the sealing action with the seal ring 27, a slip bowl having an inner downwardly and inwardly tapered surface 35a is disposed within the bore 10d and rests in contact with the upper surface of the metal ring 25. Such slip bowl 35 is urged downwardly by means of a boss 36 which is disposed above and is in contact with the upper end of the slip bowl 35. The boss 36 is urged downwardly by any suitable means, one of which is illustrated in FIGS. 1 and 2 as a threaded stud 37 which is threaded into a threaded opening ltle of the body 10 and which carries a nut 37 above the boss 36. A plurality of such studs 37, preferably three in number are employed. After each of the threaded studs 37 is threaded into the threaded bore 10a, the boss 36 is slipped over the studs 37 and the nuts 38 are tightened to move the boss 36 downwardly. Such downward movement results in a downward movement of the slip bowl 35 and therefore a downward movement of the ring 25 to compress the seal ring 27 into sealing engagement with the external surface of one of the pup joints 30.

A plurality of arcuate slip members 40 having upwardly directed slip teeth 40a and external downwardly and inwardly tapered surfaces 40b are disposed in the slip bowl 35. The tapered surface 40b on each of the slip members 40 corresponds with the taper on the internal surface 35a of the slip bowl 35 so that the slips 40 may slide downwardly and therefore move inwardly for gripping engagement with the external surface of the pup joint 30. It is to be noted that even though the teeth 40a are in gripping engagement with the external surface of the pup joint 30, the pup joint 30 and therefore the entire string S may be moved or lifted upwardly without releasing the slips 40 from contact with the pup joint 30. Also, the slips 40 may be wedged more tightly into contact with the external surface of the pup joint 30 by means of a slip boss 'which has a plurality of openings 45a therethrough for receiving the upper ends of the threaded studs 37. Each of the studs 37 has a nut 46 threaded thereon above the slip boss 45 so that upon a tightening of the nuts 46, the slip boss 45 is urged downwardly to move the slip members 40 downwardly with respect to the slip bowl 35. Thus, the pup joints 30 and therefore the entire pipe string S may be securely supported by the support assembly A.

The upper end of the pup joints 30 extends above the slip boss 45 a distance which may vary, depending upon the type of equipment which is available for the handling of the tubing string S. Normally, the tubing string S is handled by a conventional elevator in a well derrick which is adapted to fit around the external surface of the pup joints and grip same for lifting the string S to thereby place the string S under tension, when desired.

The upper end of the pup joints 30 is preferably provided with a plug 47 which is removable for the purpose of inserting a connector or another length of pipe for the handling of the tubing string S in some circumstances. The plug 47 preferably is provided with a passage 47a extending longitudinally therethrough and which communicates with a bleed port 47b. A threaded closure 48 is threaded into the threaded portion of the bore 47a so that it closes the bleed port 47b and prevents the escape of pressure during normal washing operations with the apparatus of this invention. However, prior to removing the plug 47, or breaking the seal at the seal ring 27, the extent of the pressure in the well can be determined by opening the bleed plug 48 to thereby expose the port 47b to the port 47a so that an operator can tell whether pressure within the well is so great as to require a killing of the well before removing the seal 27 and other seals that may be required to hold the well under control.

After the tubing string S has been supported by the support assembly A in substantially the position shown in FIG. 1, a washpipe W is adapted to be lowered into the well casing C through a bore 10] of the body 10. Also, a seal assembly B is mounted with the body 10 by means of a connector tube 50 which is welded at 50a to the upper end of the body 10 and which is threaded at 50b to the lower end of the seal assembly B.

Details of the seal assembly B are shown in FIGS. 3 and 4. The seal assembly B, in the preferred form, includes an upper cylinder or sleeve which has an annular retainer 61 threaded thereto at its upper end. Within the bore 60a of the cylinder or sleeve 60, there is disposed an annular sealing element 62 formed of rubber, plastic or other resilient compressible material. To facilitate the inward distortion of the sealing element 62 upon a longitudinal compression thereof, the upper end of the sealing element 62 is preferably engaged by a ring 63 formed of metal and which is disposed within a pocket provided by a shoulder 61a of the retainer 61. It is to be noted that when the sealing element 62 is in the retracted position of FIG. 3, its inner bore 62a is substantially the same as the inner bore of the retainer 61 and the ring -63.

Below the sealing element 62, an annular piston 65 is slidably disposed for longitudinal movement relative to the cylinder or sleeve 60. The upper end 65a of the piston 65 engages the lower end of the sealing element 62 so that upward movement of the piston 65 imparts the longitudinal compression to the sealing element 62 to decrease the internal diameter of the bore 62a to thereby effect a tight sealing contact with the external surface of the washpipe W, The piston 65 preferably carries an upper O-ring 65b and a lower O-ring 65c, with the upper O- ring in sealing engagement with the inner bore 60a and with the lower O-ring 650 in sealing engagement with an inner counterbore 60b. One or more vent openings 60c are provided in the wall of the cylinder 60 to permit the release of air or fluid during the longitudinal travel of the piston '65 relative to the sleeve 60 to thereby prevent a fluid lock. A coil spring 66 or other suitable resilient means is preferably disposed between a lateral shoulder 60d on the cylinder 60 and another annular shoulder 65d on the piston 65 to normally maintain the piston 65 in a lower position with the sealing element 62 in an uncompressed or retracted position (FIG. 3).

.An adapter body 70 having a tube 71 therewith for introducing hydraulic fluid to the piston 65 is provided. The tube 71 communicates with one or more internal passages 70a which extend upwardly to an annular passage 70b to thereby provide fluid pressure to the lower end of the piston 65. It is to be noted that the piston 65 has a lower extension or sleeve 65d which extends downwardly below the upper end of thepassage 70a and the passage 70band is thereby sealed off with an annular O-ring seal 65e or other similar sealing arrangement. Thus, when hydraulic fluid or other similar fluid is introduced through the tube 71 from any suitable source of fluid under pressure, it forces the piston 65 to move upwardly so as to overcome the force of the spring 66 and compress the sealing element 62 into sealing engagement with the external surface of the washpipe W. Upon a release of the fluid pressure, the spring 66 returns the piston 65 to the lower position wherein the sealing element 62 is uncompressed or retracted.

Preferably, two of the sealing elements 62 and the pistons 65 are employed and therefore a duplicate construction is provided therebelow. For ease of illustration, such duplicate structure has been omitted between the hydraulic inlet tube 71 and the lower hydraulic inlet tube 171 which corresponds thereto. The adaptor body 170 which mounts the tube 171 therewith corresponds with the adapted body 70. Also, the sleeve or piston extension 165d corresponds with the sleeve or piston extension 65d in the lower seal portion which is not shown in the drawings.

The extension or sleeve 165d normally extends below the inlet tube 171 so as to engage a plurality of pivoted dogs 80 which form a safety catch mechanism. Each of the dogs 80 is pivotally mounted at a pivot pin 80a, and e'ach is resiliently urged from the substantially vertical position of FIG. 3 towards the substantially horizontal position of FIG. 4 by means of resilient springs 81 or any other suitable resilient means. The extent of the upward pivoting of the dogs 80 is limited by the engagement of the upper surfaces thereof with a stop ring 82 and with the lower end of the sleeve 165d, as best seen in FIG. 4.

The sleeve 165d is in the lower position shown in FIG. 3 when the piston to which it is connected is in its lower position corresponding to the position of the piston 65 in FIG. 3 and therefore when the seal ring 62 is in the uncompressed condition and the seal ring associated with the extension 165d is also in the uncompressed position. Therefore, during the running in of the wash tube W, the seal rings 62 and the other seal ring which is a duplicate thereof and is not shown are both in the retracted or "uncompressed positions while the sleeve 165d is in its lower position to hold the catch dogs or fingers 80 in the retracted position, whereby the Wash tube W may be moved longitudinally through the sealing assembly B without interference or obstruction in either direction.

However, when the fluid is introduced into the sealing assembly B through the

inlet tubes

71 and 171, the sealing elements 62 and its counterpart therebelow are moved into sealing engagement with the washpipe Wand the extension 165d is moved upwardly to the position shown in FIG. 4 so that the dogs 80 swing upwardly to the position of FIG. 4 which enables them to restrict the upward movement of the washpipe W. Such restriction on-the upward movement of the washpipe W is obtained because the dogs 80 extend'into the bore of the sealing assemblyB a suflicient distance to be engaged by the upset'or joint 85 of the washpipe W which is just below the safety catch means provided by the dogs 8Q. T herefore, in the event of an increase in pressure tending to move the washpipe W upwardly and which might thereby result in a blowout of the well, the washpipe W is caught by the dogs 80 and is prevented from being blown out of the well.

In the operation or use of the apparatus of FIGS. l-4 of thisinvention, and in performing the method of this inventionusing the apparatus of FIGS. 1-4, the tubing string S is supported in the well casing C by the support assembly A as previously described, preferably in the position offset from the center of the well casing C so as to allow clearance for the positioning of the wash tube W along side the tubing string S. The tubing string is normally stuck so that it cannot be freely moved when initially using the apparatus of this invention. The well may be kept under control by introducing drilling mud or other relatively high density liquid during the placing of the head 10 and the supporting assembly A in position for supporting the tubing string S. After the washpipe W has been positioned through the sealing assembly B and the seals therewith have been engaged with the washpipe W, the mud or other liquid may be removed by introducing washing fluid into the well casing or into the washpipe W so that fluid circulation is either through thewashpipe W and out through the tube 16 or vice versa. The washing action with the washing fluid is provided to wash the sand or similar obstruction from around the tubing string S at or near the usual well packer or in any other location to thereby free the stuck tubing string S.

In carrying out the method, the operator pulls upwardly on the tubing string S to place the string S under tension from its stuck point upwardly to the slips 40. Such tensioning tends to straighten the string S down to the stuck point so that the washpipe W can be lowered relative thereto. As previously explained, the upper pup joints 30 of the tubing string S may be engaged by a conventional pipe elevator in a derrick to effect such lifting and tensioning of the tubing string S, and since the slip teeth 40a do not prevent upward movement of the string S but hold the tension thus applied to the string S, the string S is held in the stretched or tension condition. While the string S is under tension, the washpipe can be lowered downwardly around the string S to the upper part of the sand or other solids in the well above the packer, where washing is etfected to loosen and wash up the sand or solids so as to circulate same to the surface for removal through the tube 16.

After washing is continued long enough to loosen at least a portion of the stuck string, the loosening of the portion of the string may cause the string to have bccome slack; so, the operator again pulls upwardly on the string S to place the entire length of the string S down to the stuck portion under tension. The washpipe W is then lowered further around the loosened portion of the string to the solids, and washing is continued to loosen and wash up more of the sands or other solids to the surface by the fluid circulation to thereby loosen more of the stuck portion of the string S.

If the pipe or string S is still stuck after such pulling and testing, additional tensioning of the string S and lowering of the washpipe W with washing is effected and the circulation continued until the solids have been sufficiently loosened or removed to effect a freeing of the string S.

When it has been determined by a lifting upwardly on a tubing string S that such string S is no longer stuck, the safety plug 48 may be unthreaded to open the port 47b to bleed any pressure therethrough which may be present within the tubing string S. If an excessive amount of pressure is present in the well as indicated by such bleeding action, it is necessary to then again introduce drilling mud or a heavy liquid to bring the well under control before removing the seals around the tubing string S and the washpipe W. The washpipe W and the tubing string S are then removed so that repairs or replacements can be accomplished. The tubing string S, in new or repaired condition, then is inserted into the casing C and then the Christmas tree is placed back on the spool 12 in the conventional manner. At all times, the well is maintained under control with the heavy mud. With the well thus ready for operation, the well is swabbed or other means are used to remove the heavy mud so that production in the usual manner can be resumed.

In the form of the invention illustrated in FIGS. and 6, multiple tubing strings S1 and S2 are illustrated to show the applicability of the present invention to wells having multiple production tubing strings. The tubing strings S1 and S2 are supported in-a hanger body 110 which has a hanger or support assembly A-1 removably mounted therein, and which may be of conventional construction. The hanger body 110 is connected to a spacer spool 112 which in turn is connected to an upper flange 114b connected to the upper ends of the typical well casing C. Although only one spool 112 is illustrated, several of such spools may be employed, depending upon the length of the pup joints 130 which are mounted in each of the strings S-1 and S2 for the tensioning of such strings during the carrying out of the methods of this invention, as will be more fully explained. The lower end of the spool or spacer 112 is bolted to the casing C by a coupling collar 114 which includes the flange 114b on the upper end of the casing C and also another flange 114a on the lower end of the spool 112. Suitable retaining bolts 115 of conventional construction and corresponding to bolts 115 of FIG. 1 are employed for bolting up the flanges 114a and 114b, as will be well understood.

The upper end of the spool 112 is similarly bolted by means of coupling flanges 117a and 117b which are bolted together by a plurality of bolts 121. Fluid flow pipes 116 which correspond with the fluid flow pipes 16 of FIG. 1 are part of the hanger body 110. It is to be noted that the spool 112 and the hanger body 110 take the place of the typical Christmas tree normally connected above the casing C for the production of oil or gas from the well.

In the form of the invention shown in FIG. 5, the upper end of the hanger body 110 is closed by means of a cover plate 110a which is held in position by any suitable means such as bolts or screws 118 which are suitably spaced around the circumference of the plate 110a and a flange 11011. An opening or bore 110a is provided in the plate 110a through which the washpipe W extends. The washpipe W may be positioned in the same type of seal assembly B illustrated in connection with FIGS. 14. The seal assembly B is secured to the flange 110a by means of screws or bolts 119 or any other suitable securing means. A conventional blowout preventer (not shown) may be used in conjunction with the washpipe W in FIG. 5 and also in FIG. 1.

The washpipe W has a nozzle 90 at its lower end with a jet opening in the form of a carbide tubular insert 90a disposed therein at an angle to the longitudinal axis of the washpipe W. It has been found that the washing action around stuck tubing strings is more readily effected by a single jet or insert 90a which is disposed at an angle of approximately 15 degrees to 30 degrees with respect to the longitudinal axis of the washpipe W. With such arrangement, the washpipe W may be rotated so as to vary the direction of the jetting fluid as it discharges into the sand or other solids around the stuck portion of the pipe or pipes S-1 and S2. The particular angle at which the jet insert 90a is disposed may be varied so long as the fluid is discharged with swirling or turbulent action around the stuck pipe strings. Although more than one jet 90a may be utilized in the nozzle 90', it is diflicult to dispose a plurality of jets so that their jet discharge streams do not counteract each other in the washing action, and therefore, a single jet is the most satisfactory.

The pup joints 130 at the upper end of each of the strings S-1 and S2 preferably include a plug 147 which is similar to the plug 47 of FIG. 1, and which also has a bleed plug 148 therewith for exposing a port 147d so that the operator can tell whether the pressure within the well is so great as to require a killing of the well before removing the tubing strings S-1 and S2 from the well. The bleed port 147b is normally closed by the plug 148, but when the plug 148 is threaded upwardly, communication i established between the port 147b and the main port 147a in plug 147.

It is to be noted that the pipe strings S1 and S2 are carried in tubing hanger elements or segments 92 which are separate from each other and which are adapted to fit downwardly within the tubing hanger bowl 110d for resting upon the supporting angular shoulder 110e. The washpipe W passes through a segment 93 which completes the tubing hanger A-l, but it is to be noted that the washpipe W moves longitudinally with respect to the hanger A1 for the washing action in carrying out the method of this invention with multiple pipe strings, as will be more fully explained.

The uppermost normal pipe joint 131 in the pipe string 8-1 is at approximately the upper end of the casing C at the time the pup joints 130 are added thereto, although this location or elevation may vary depending upon the condition of the tubing string 8-1 at the time the joints 130 are connected. The same situation exists with respect to the other tubing string S2.

In carrying out the method of this invention, using the apparatus of FIGS. 5 and 6, the same general procedure used in connection with the apparatus of FIGS. l-4 is followed. However, since the strings S1 and S2 are disposed below the plate 110a, the well must be under control and the plate 110a must be removed in order to place the strings S1 and S2 under tension prior to the washing action.

Therefore, with the spool 112 and the body hanger 110 in position on the upper end of the casing C, and with the well held under control with drilling mud or other heavy fluid, the upper end of the uppermost pup joint 130 on each of the strings S1 and S2 is engaged by a pulling device at the derrick or any other suitable pulling means to pull upwardly on the entire tubing string down to the stuck portion to place the tubing string S1 and also the tubing string S2 under tension. The strings Sl and S2 may be placed under tension separately or simultaneously. With such tubing strings S1 and S2 under tension, the upper ends of the tubing strings are lowered slightly to seat the tubing hanger elements or segments 92 and 93 in the bowl 110d of the hanger body 110. The tubing strings S1 and S2 are thus supported under tension to render them substantially straight so that the washpipe W may thereafter pass downwardly alongside such tubing strings within the casing C. If such strings S1 and S2 were not under tension and straightened in the casing, the space between the strings and the casing may be inadequate to even move the washpipe W downwardly to the sand or solidified material.

The plug 147 is inserted and then the flange 110a is placed over the tubing hanger body 110 and is bolted in position as shown in FIG. 5. The seal assembly B is also mounted on the flange 110a and the washpipe W is lowered downwardly therethrough.

When the nozzle has reached the vicinity of the upper portion of the sand or other solid material within the casing C which is causing the tubing strings S-1 and S2 to be stuck in the casing C, the washing fluid is discharged from the nozzle 90 through the, jet opening or insert 90a at an angle to swirl around in either a clockwise or counterclockwise direction so as to wash the sand and other solidified material from around the entire circumference of both of the strings S1 and S2. Such solidified material is thus loosened and washed up and circulated out through the discharge openings 116 in the hanger body (FIG. 5).

As the washing continues, a portion of the stuck part 9 the tubing strings S1 and S2 becomes loosened, and a suflicient amount of loosening may occur to free the strings for removal from the well. On the other hand, if the strings S-1 and S2 are not completely free, the tubing strings S-1 and S2 may have to be tensioned again to permit the further lowering of the washpipe W downwardly to the solidified material. This is because the stuck portion of the pipe was in a slack condition and is curled or distorted in its direction and therefore it blocks the longitudinal movement downwardly of the washpipe until the tubing strings are placed in tension again. 7

To place the tubing strings S-1 and 5-2 in tension again, the seal assembly B and the plate 110a are removed, being careful to keep the well under control with well mud or fluid. Thereafter, using any suitable lifting equipment, the upper ends of the strings S-1 and 5-2 are pulled upwardly to again place the tubing strings under tension. It may be necessary-to remove one or more of the pup joints 130 in each of the strings S-1 and 8-2 so that the strings will be under tension when reseated in the tubing hanger bowl 110a. If the pup joints 130 are removed, the hanger segments 92 are replaced on the upper end of the uppermost pup joint in each of the strings which is left after such removal of the excess pup joint or joints. Thus, the strings S-1 and 5-2 are again supported in tension by the hanger elements 92, and the plate 110a is returned to the closed position shown in FIG. 5. The seal assembly B is also returned to its position over the washpipe W. The washpipe W can then be further lowered to the uppermost part of the solidified material which has not been loosened, and the washing action is then resumed to loosen and wash up to the surface more of the sand or solidified material. Such method is continued until a suflicient amount of the solidified material has been loosened or removed to enable the pulling of the strings S-1 and 5-2.

It should be noted that the method of this invention is accomplished without the use of free point indicator apparatus or any backing off of the tubing strings down in the well as in the prior practice.

I claim:

1. A method of freeing stuck pipe in a well casing, comprising the steps of:

(a) pulling upwardly on the stuck pipe to place said pipe in tension from its stuck point upwardly in the well;

(b) lowering a washpipe alongside the pipe in the well casing and down to a point in proximity to the solids causing the stuck condition of the pipe;

(c) circulating washing fluid through the washpipe and the casing to loosen or wash up the solids to the surface; and

(d) maintaining the tension on the stuck pipe during the lowering of the washpipe and the circulating of washing fluid to provide sufficient space alongside the stuck pipe from the longitudinal movement of the washpipe.

2. The method set forth in claim 1, including the steps of:

(a) pulling upwardly on the stuck pipe after Washing to determine whether it has been freed; and

(b) again placing the stuck pipe under tension if it has not been freed and repeating the circulating step with the washing fluid in proximity to the solids while the stuck pipe is in tension to loosen or wash up additional solids in a further attempt to free the stuck pipe.

3. The method set forth in claim 1, wherein:

(a) the stuck pipe includes multiple pipe strings disposed in the well casing; and

(b) the circulating of the washing fluid is effected with a jet stream which washes around the pipe strings for loosening or washing up the solids in the casing.

4. The method set forth in claim 1, including:

(a) turning said washpipe while discharging washing fluid in a jet stream therefrom for washing around the stuck pipe to effect the loosening or washing up of the solids in the casing.

5. Well workover apparatus for use with a well having a well casing with a tubing string disposed therein, comprising:

(a) a body adapted to be mounted above the upper end of the well casing and having a substantially vertical :tubing string opening and a substantially vertical washpipe opening, the outer edges of said openingsextending no further laterially than the inside surface of the casing;

(b) tubing string support means with said body for supporting the tubing string with respect to the casing;

(c) a substantially straight washpipe disposed in said washipipe opening and extending downwardly into the well casing alongside the tubing string for the circulation of washing fluid therethrough;

(d) said tubing support means having means for preventing the tubing string from moving downwardly after-a pull is taken on the tubing string; and

(e). means for mounting said washpipe for longitudinal movement in said casing relative to said tubing string support means.

6. The structure set forth in claim 5, including:

(a) washpipe seal means with said body for sealing around the washpipe for confining the flow of wash fluid therebelow in the casing during the washing of solids from the stuck point of the tubing string.

7. The structure set forth in claim 6, wherein:

(a) said washpipe seal means is releasable from sealing contact with said washpipe for permitting fluid flow around the washpipe.

8. The structure set forth in claim 5, including:

(a) multiple tubing strings disposed in the well casing;

and

(b) said tubing string support means being adapted to support said multiple tubing strings for maintaining tension thereon during the circulation of washing fluid.

9. The structure set forth in claim 5, including:

(a) a nozzle on the lower end of said washpipe having a jet opening disposed at an angle with respect to the longitudinal axis of the washpipe for washing around the stuck pipe.

10. The structure set forth in claim 5, including:

(a) multiple tubing strings disposed in the well casing;

(b) said tubing string support means being adapted to support said multiple tubing strings for maintaining tension thereon during the circulation of Washing fluid; and

(c) a nozzle on the lower end of said washpipe having a jet opening disposed at an angle with respect to the longitudinal axis of the washpipe tor washing around the stuck pipe.

References Cited UNITED STATES PATENTS 2,153,852 4/1939 Tschappat 285-148 2,830,665 4/1958 Burns et a]. 166-75 2,927,638 3/ 1960 Hall 16684X 3,028,917 4/1962 Rhodes 166-75 3,134,613 5/1964 Regan 285 3,142,336 7/1964 Doscher 16667X ERNEST R. PURSER, Primary Examiner U.S. Cl. X.R.