CONTINUOUS FLUID CIRCULATION VALVE FOR WELL DRILLING

Abstract

Fluid circulation valve (10) is provided for use with a well drilling operation, so that a drill joint may be added to or removed from the drill string while circulating fluid into the well. Valve housing (16, 12) has a central flow path therein, a housing side port (87), and upper and lower threaded connectors for engagement with the drill joint and the drill string, respectively. A rotatable ball (24) is positioned within the flow path in the valve housing and a ball side port (15) in fluid communication with the housing side port (87) when the ball is closed. A tool (80) is provided for engaging the valve housing and sealing between an interior of the valve housing and the radially external flow line, which passes fluid into the well when a drill joint is being connecting to the upper end of the valve.

Description

FIELD OF THE INVENTION

The present invention relates to a method and equipment for drilling a well. More particularly, a circulation valve is provided for interconnection with a drill string joint, such that during conventional drilling the fluids pass through the drill string joint, the valve, and the drill string in the well. When the drill string connection is made up or broken apart, fluid is diverted through a side port in the valve, thereby maintaining substantially continuous fluid circulation.

BACKGROUND OF THE INVENTION

When drilling a hydrocarbon recovery well, the drill string is conventionally rotated to drive the drill bit. When a mud motor is used along the drill string to rotate the bit, the drill string is frequently rotated at a speed less than the bit to keep solids desirably suspended in the well fluids. Drilling mud is thus circulated through the drill string and to the bit, and up the annulus between the drill string and the wellbore. As one or more joints are added to the string, the drilling process is briefly stopped to make up the threaded interconnection of the joint to the drill string. Although the drill string is normally full of fluid, the pressure supplied by the mud pumps is lost when the pumps are shut off as the threaded connection is made up. Restarting circulation can be difficult, and may lead to numerous drilling problems.

The prior art includes methods designed to allow a drill joint to be added to or removed from a drill string while circulation of mud continues. This prior art process utilizes a coupler for substantially surrounding the threaded connection. Various rams, preventers, slips, and other closing devices substantially seal fluid within the coupler as the connection is made up. Devices of this type are disclosed in U.S. Pat. Nos. 6,119,772, 6,591,916, 6,739,397, 7,028,586, and 7,252,151. Publication WO98/16716 also discloses a continuous circulation drilling method.

There are significant disadvantages to the above approach. First, the mechanism for accomplishing continuous circulation involves an expensive coupler, and numerous sealing devices are provided to minimize leakage of mud from the encircling coupler. The device is also expensive, and at least in some applications slows down the makeup or breakout process, thereby contributing to higher drilling costs. U.S. Pat. No. 4,478,244 discloses a mud saver valve which may be threaded to a drill string to reduce mud spills. U.S. application Ser. No. 11/786,495 discloses a safety valve with a ball rotatable engaging an actuator sleeve.

The disadvantages of the prior art are overcome by the present invention, in an improved technique for continuously circulating drilling mud in a drill string is hereinafter disclosed.

SUMMARY OF THE INVENTION

In one embodiment, a fluid circulation valve is provided for use with a well drilling operation, wherein a drill joint may be added to or removed from a drill string which extends into a well. The fluid circulation valve includes a valve housing having a central flow path therein, a housing side port, an upper threaded connector for threaded engagement with the lower end of the drill joint, and a lower threaded connector for threaded engagement with an upper end of the drill string. A rotatable ball is positioned within the flow path in the valve housing has a throughbore. The ball throughbore is in fluid communication with the housing central flow path when the ball is open, and a ball side port is in fluid communication with the housing side port when the ball is closed. The valve housing side port is in fluid communication with a line radially exterior of the valve housing, and typically extending to a mud pump. The fluid circulation valve includes an upper valve seat for sealing between the ball and the housing, and a lower valve seat for sealing between the ball and the housing. Fluid may be continuously circulated through the drill string even when adding or deleting a drill joint, since fluid may flow either through the ball throughbore or though the ball side port. The valve remains connected to the drill string as joints are added and the string is run in the well. The housing side port is closed when the ball throughbore is in fluid communication with the valve housing central flow path. The upper side of valve throughbore is closed when the ball is positioned to open the side port into the interior of the housing.

These and further features and advantages of the present invention will become apparent from the following detailed description, wherein reference is made to the figures in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of one embodiment of a fluid circulation valve.

FIG. 2 is a cross-sectional view through the valve shown in FIG. 1.

FIG. 3 is a top view illustrating a suitable tool for sealing between the valve body and a radially external flow line.

FIG. 4 is a cross-sectional view of another embodiment of a fluid circulation valve, with two circumferentially opposing operating stems for rotatably guiding rotation of the ball.

FIG. 5 is a cross-sectional view of yet another embodiment of a fluid circulation valve.

FIG. 6 illustrates the fluid circulation valve shown in FIG. 5 in another ball position.

FIG. 7 illustrates a tool for sealing between the valve body and a radially external flow line.

FIG. 8 is a cross-sectional view of yet another embodiment of a fluid circulation valve, wherein the ball actuator is axially spaced from the ball.

FIG. 9 illustrates the fluid circulation valve in FIG. 8 in the closed position.

FIG. 10 illustrates a tool for sealing between the valve body and a radially external flow line.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 illustrates one embodiment of a fluid circulation valve according to the present invention. Circulation valve 10 includes a valve body, which as shown consists of an upper valve body 16 having upper threads 18 for threaded interconnection with the lower end of a pipe joint, and a lower valve body 12 having lower threads 14 for threaded connection with an upper end of a tubular string which extends into a wall. The bodies 12 and 16 are joined by threads 20, with shoulder 22 acting between the bodies 12 and 16 to obtain a rigid connection, and to pass torque from above the valve to below the valve while positioned along a drill string, thereby allowing torque to be transferred to the bit to rotate the bit, or to actuate components along the drill string. A seal 30 may be provided for sealing between the housings 12 and 16. Those skilled in the art will appreciate that fluid may be pumped through the valve from the upper end of a pipe joint to the lower end of the pipe joint, then through the bodies 16 and 12, then through a tubular pipe string which extends into a well.

FIG. 1 illustrates a ball 24 rotatably positioned within the valve housing, with the ball having a throughbore 41 defined by side walls 42, such that the throughbore 41 is in fluid communication with the bore 17 in the housing when the ball is in the open position, as shown in FIG. 1. Mud or other drilling fluid may thus be pumped from above the fluid circulation valve, through the fluid circulation valve, and into the drill string when the valve 10 is open.

The circulation valve preferably includes an upper valve seat 28 which has a seal 32 for sealing engagement with the housing 12, and another seal 32 for sealing engagement with the ball 24. The assembly further includes a lower ball seat 26 similarly having a seal 32 for sealing engagement with the housing 16, and another seal 32 for sealing with the ball 24. One or more biasing members, such as a wave spring or a Beliville spring 27, may be included to bias upper seat 28 axially downward for sealing engagement with the ball, or to bias the lower seat 26 upward into sealing engagement with the ball. Each seat thus may include a Beliville spring or a wave spring to exert a desired biasing force to press the seat into engagement with the ball. FIG. 1 also illustrates an operating stem or guide block 34 with seal 36 for sealing engagement with the housing 16, a noncylindrical external access pocket 38 for receiving a ball rotating tool, and a noncylindrical actuating tab 40 for fitting within a similarly shaped recess within the ball to rotate the ball when the operating stem or guide block 34 is rotated, as explained hereafter.

FIG. 2 is a horizontal cross sectional view through the valve and the ball in FIG. 1, with the ball 24 in the open position. The operating stem 34 is shown with a radially inward key 40 (see FIG. 1) for inserting into a key into a receiving pocket in the ball 24, so that the ball rotates in response to rotation of the operating stem 34. The flange 33 retains the operating stem in position with respect to the valve housing, thereby monitoring the ball centered in spite of high pressure acting on the operating stem. FIG. 2 also discloses an inlet ring 44 which is threaded at 46 into engagement with the housing 16, and is configured for fluidly receiving an external flow line, as disclosed subsequently.

FIG. 3 shows a suitable tool 80 for engaging an outer surface of the housing 16, and for temporarily sealing between the interior of valve 10 and a flow line 82 radially external of the valve, with line 82 typically extending to a mud pump 83. The exemplary tool has an arcuate portion 81 which substantially surrounds the valve body 16, with curved interior surface 84 engaging the exterior surface of valve body. The tool 80 includes a latch-type locking lugs 50 and 54, locking handle 52, and at least one hollow pin 86 which fits within a respective cavity or recess in the ring 85 when the handle is locked. Hinge 83 allows the ring shaped tool to be easily put on and removed from the valve. FIG. 3 also illustrates seal 87 for acting between the tool and the ring 85, which defines the cavity or recess for receiving the external fluid. The ball 24 is shown in FIG. 3 in the closed position, i.e., fluid is blocked from flowing from above to below the valve, although fluid can flow from exterior flow line 82 to the ball and then downward into the drill string. Other types of tools may be used for sealingly engaging the valve body and the external flow line.

FIG. 4 is similar to the FIG. 2 embodiment, except that a pair of circumferentially opposing guide blocks or operating stems 34, 35 are provided, each with a tool recess pocket 38. One or both operating stems may thus be rotated to rotate the ball between open and closed positions. In one embodiment, one stem may be connected to the ball 24 for rotating the ball to the open position and the opposing stem rotated to move the ball to the closed position, as shown in FIG. 3. Two radially opposing operating stems allow fluid pressure to act on both operating stems, so that the opposing forces cancel and the ball remains centered in the valve body without using the flange 33 shown in FIG. 3. Also, FIG. 4 depicts spring biased pins 56, 58 for exerting a biasing force from the housing to the ball, and similar spring biased pins 57, 59 for exerting a biasing force from ring 44 to the ball.

Referring now to FIG. 5, this version of a continuous fluid circulation valve 10 is depicted with a ball valve 24 shown in the open position for transmitting fluid from above to below the ball valve. By rotating the operating stem 34, the ball may thus be rotated between the open and closed positions. FIG. 6 illustrates another cross sectional view of the valve shown in FIG. 5, and illustrates another ring 62 threadably positioned within the side body access port in the valve body, and a flapper member 66 pivotably connected to the ring member 62 and closing off the side port of the valve body when the valve is in the open position, as shown in FIG. 6. FIG. 7 depicts in greater detail a suitable tool 80 as previously disclosed for fluidly connecting flow line 82 to the interior of the valve. The tool 80 thus seals to the ring 62, as previously discussed. With the ball rotated to the closed position, fluid may be pumped into the valve body, and fluid pressure will be sufficient to swing the flapper 66 to the open position, as shown in FIG. 7, thereby allowing fluid to enter the interior of the ball and pass downward through the valve and into the drill string.

FIG. 8 depicts another version of a continuous circulation valve 10 according to the present invention, with a ball 24 as previously discussed. In this embodiment, the ball is rotated between an open and closed position and by rotating sleeve 72, which includes threads 74 for mating with sleeve 76 extending axially from connector 78, which interconnects the sleeve 76 with the ball. By rotating the sleeve 72, the sleeve 76 moves axially relative to the housings 16, 12, thereby rotating the ball. A large pipe wrench or other suitable tool may be used for gripping the external surface of sleeve 72 to rotate the sleeve and thereby the ball between open and closed positions. FIG. 10 illustrates a suitable tool 80 for sealingly engaging external flow line 82 to the interior of the ball when the valve is in the closed position. As with the prior embodiments, the tool is sealed to threaded ring 85 for passing fluid from a line radially exterior of the ball valve into the well when the flow line from above to below the ball valve is blocked.

In other embodiments, one of the rotating sleeve 72 and the ball rotating member may include one or more projections which each fit within a corresponding helical slot in the other of the rotating sleeve and the ball rotating member, so that rotation of the sleeve moves the ball rotating member axially in the same manner as the threads discussed above. Threads are preferred for most applications since they provide a large surface area for transmitting axial forces to the ball to open or close the ball.

The term “ball” as used herein is intended in its broad sense to refer to a rotatable closing member in a valve, with at least a portion of the outer surface of the ball being similar in configuration to a portion of a sphere. While the ball as disclosed herein obviously need not be a sphere, the ball does rotate about a ball center.

The fluid circulation valve as disclosed herein may be used in well drilling operations wherein fluid passes through a drill joint, through the valve, and into the drill string while the valve is in the open position, and fluid passes from an external flow line, downward through a lower end of the valve body, and into the drill string when the valve is closed. During the valve closed cycle, the drill joint may be fluidly connected with the top of the valve, and once this connection is complete, the valve may be opened so that the external flow line is blocked and fluid can be pumped into the well through the drill joint, which is now part of the drill string.

Although specific embodiments of the invention have been described herein in some detail, this has been done solely for the purposes of explaining the various aspects of the invention, and is not intended to limit the scope of the invention as defined in the claims which follow. Those skilled in the art will understand that the embodiment shown and described is exemplary, and various other substitutions, alterations and modifications, including but not limited to those design alternatives specifically discussed herein, may be made in the practice of the invention without departing from its scope.

Claims

1. A fluid circulation valve for use in well drilling with a drill joint and a drill string extending into the well, comprising:

a valve housing having a central flow path therein, an upper threaded connector for threaded engagement with a lower end of a drill joint, a lower threaded connector for threaded engagement with the upper end of a drill string, and a housing side port for fluid communication a flow line radially exterior of the valve housing;

a ball rotatably positioned within the flow path and having a throughbore, the ball throughbore being in fluid communication with the housing central flow path when the ball is open, and the ball including a ball side port in fluid communication with the housing side port when the ball is closed;

an upper valve seat for sealing between the ball and the housing; and

a lower valve seat for sealing between the ball and the housing.

2. A fluid circulation valve as defined in claim 1, wherein a biasing member biases the upper valve seat toward the ball.

3. A circulation valve as defined in claim 1, further comprising:

a tool removably engagable with the valve housing to seal between an interior of the valve housing and the flow line radially exterior of the valve housing.

4. A circulation valve as defined in claim 3, wherein the tool engages the housing side port for sealing with the exterior flow line.

5. A circulation valve as defined in claim 1, further comprising:

a rotatable operating stem positioned within the valve body for engaging the ball and rotating the ball to move between open and closed positions.

6. A circulation valve as defined in claim 7, wherein the operating stem comprises a pair of circumferentially opposing operating stems.

7. A circulation valve as defined in claim 1, wherein a minimum cross sectional flow area of the valve housing central flow path is substantially the minimum cross section flow area of the ball throughbore.

8. A circulation valve as defined in claim 1, wherein the valve housing comprises an upper valve body and an interconnected lower valve body.

9. A circulation valve as defined in claim 1, further comprising:

a ball rotator spaced axially from the ball, the ball rotator rotatable with respect to the housing to rotate the ball between open and closed positions.

10. A fluid circulation valve for use in well drilling with a drill joint and a drill string extending into the well, comprising:

a valve housing having a central flow path therein, an upper threaded connector for threaded engagement with a lower end of a drill joint, a lower threaded connector for threaded engagement with the upper end of a drill string, and a housing side port for fluid communication a flow line radially exterior of the valve housing;

a ball rotatably positioned within the flow path and having a throughbore, the ball throughbore being in fluid communication with the housing central flow path when the ball is open, and the ball including a ball side port in fluid communication with the housing side port when the ball is closed; and

a tool removably engagable with the valve housing to seal between an interior of the valve housing and a flow line radially exterior of the valve housing.

11. A circulation valve as defined in claim 10, further comprising:

an upper valve seat for sealing between the ball and the housing.

12. A fluid circulation valve as defined in claim 11, further comprising:

a biasing member biases the upper valve seat toward the ball.

13. A circulation valve as defined in claim 10, wherein the tool engages the housing side port for sealing with the exterior flow line.

14. A circulation valve as defined in claim 10, wherein a minimum cross sectional flow area of the valve housing central flow path is substantially the minimum cross section flow area of the ball throughbore.

15. A circulation valve as defined in claim 10, wherein the valve housing comprises an upper valve body and an interconnected lower valve body.

16. A circulation valve as defined in claim 10, further comprising:

an operating stem positioned within the valve body for engaging the ball and rotating the ball to move between open and closed positions.

17. A fluid circulation valve for use in well drilling with a drill joint and a drill string extending into the well, comprising:

a valve housing having a central flow path therein, an upper threaded connector for threaded engagement with a lower end of a drill joint, a lower threaded connector for threaded engagement with the upper end of a drill string, and a housing side port for fluid communication a flow line radially exterior of the valve housing;

a ball rotatably positioned within the flow path and having a throughbore, the ball throughbore being in fluid communication with the housing central flow path when the ball is open, and the ball including a ball side port in fluid communication with the housing side port when the ball is closed;

an operating stem positioned within the valve housing for engaging the ball and rotating the ball between open and closed positions; and

a tool removably engagable with the valve housing to seal between an interior of the valve housing and a line radially exterior of the valve housing.

18. A fluid circulation valve as defined in claim 17, further composing:

an upper valve seat for sealing between the ball and the housing; and

a biasing member biases the upper valve seat toward the ball.

19. A circulation valve as defined in claim 17, wherein the guide block comprises a pair of circumferentially opposing guide blocks.

20. A circulation valve as defined in claim 17, further comprising:

a ball rotator spaced axially from the ball, the ball rotator rotatable with respect to the housing to rotate the ball between open and closed positions.