US3877529A

US3877529A - Method of assembling drill string using fluid saver valve

Info

Publication number: US3877529A
Application number: US484814A
Authority: US
Inventors: Mason Rawleigh Litchfield
Original assignee: Smith International Inc
Current assignee: Smith International Inc
Priority date: 1973-02-26
Filing date: 1974-07-10
Publication date: 1975-04-15
Anticipated expiration: 1992-04-15

Abstract

A method of drilling in which drill string sections are added to a drill string with minimal loss of drilling fluid. A valve sub is located below the kelly and the outer housing of the valve sub comprises the valve actuator. In disassembling the sub from a pipe string, gripping of the sub while relatively rotating the pipe string will cause the valve to be closed before the joint is broken. In reconnecting the sub to the string, the valve will be opened as the connection is made.

Description

United States Patent [1 1 Litchfield METHOD OF ASSEMBLING DRILL STRING USING FLUID SAVER VALVE [75] Inventor: Mason Rawleigh Litchfield,

Houston, Tex.

[73] Assignee: Smith International, Inc., Midland,

Mich.

[22] Filed: July 10, 1974 21 Appl. No.: 484,814

Related US. Application Data [62] Division of Ser. No. 335,489, Feb. 26, 1973.

[52] US. Cl. 175/65; 166/775; 166/315; 175/218 [51] Int. Cl E211) 19/16 [58] Field of Search 166/315, 77.5, 224; 175/65, 85, 218; 173/57, 164; 251/248-251 [56] References Cited UNITED STATES PATENTS 3,075,589 1/1963 Grable et a1. 175/218 X 1 Apr. 15, 1975 3,212,578 10/1965 Hasha 175/85 X 3,331,385 7/1967 Taylor 175/218 X 3,398,928 8/1968 Fredd 251/251 Primary ExaminerErnest R. Purser Attorney, Agent, or Firm-Murray Robinson 5 7] ABSTRACT A method of drilling in which drill string sections are added to a drill string with minimal loss of drilling fluid. A valve sub is located below the kelly and the outer housing of the valve sub comprises the valve actuator. In disassembling the sub from a pipe string, gripping of the sub while relatively rotating the pipe string will cause the valve to be closed before the joint is broken. ln reconnecting the sub to the string, the valve will be opened as the connection is made.

5 Claims, 6 Drawing Figures METHOD OF ASSEMBLING DRILL STRING USING FLUID SAVER VALVE This is a division of application Ser. No. 335.489 filed Feb. 26. 1973.

BACKGROUND OF THE INVENTION a. Field of the Invention This invention pertains to valves and more particularly to a valve assembly of the type known as a kelly foot valve or mud saver and safety valve used in the rotary system of drilling wells.

b. Description of the Prior Art In drilling oil or gas wells or the like by the rotary drilling method. a drilling fluid. known as drilling mud. is pumped from a surface reservoir. called a mud pit. to a swivel suspended from the draw works of the derrick and downwardly from the swivel through a string of drill pipe to a rotary bit at the bottom of the well bore. The mud is ejected at high velocity through a number of ports extending through the walls of the bit and is circulated up the annulus between the drill pipe and wall of the well bore and back to the mud pit for recirculation. The drilling mud provides a rapid. continuous removal of rock cuttings from the well bore.

prevents the caving and sloughing of poorly consolidated or friable rock formations. maintains a sufficient pressure on the walls of the well bore to prevent a blowout and well damage when unexpected high pressure reservoirs are encountered. and cools and lubricates the drill pipe and bit as they rotate against the abrasive rock formations.

To permit the satisfactory performance of these func tions. the mud must be closely controlled. Ordinarily. the drilling mud comprises a suspension of natural clays in water. oil. or an emulsion of water and oil. The addition of varying amounts of mud chemicals or wetting agents is determined by the specific requirements regarding viscosity. density. thixotropy. acidity. gel strength. shear strength and other properties that might be required in a particular situation.

The force rotating the string of the drill pipe is provided by a rotary table located on the rig floor. In order that the rotary table will have a positive grip on the drill string. the upper end of the string is provided with a joint of pipe called a kelly. having a polygonal crosssection designed to fit a similarly shaped opening in a kelly drive bushing of the rotary table. The kelly. which is approximately 50 feet long. is connected in the drill string from the swivel suspended from the draw works and passes through the kelly bushing in the rotary table to the upper joint of drill pipe.

Each time a joint of pipe is added to the drill string. the mud pumps. creating up to 2.000 pounds more or less per square inch on the mud. are shut down and the lower end of the kelly is lifted above the rig floor and disconnected from the drill string. The column of mud that was contained in the kelly. when circulation was halted. then flows onto the rig floor.

The volume of mud required for the drilling of a 15.000 foot well would be l.000-2.000 barrels and might constitute as much as 20% of the total drilling costs; therefore. any innovation that reduces the amount of mud required to drill a particular well reduces the cost. During the drilling ofa 15.000 foot well. the operation of disconnecting the kelly from the drill string is performed approximately 500 times with a loss each time of over /2 barrel of mud plus the cost of idle rig time and wasted man-hours while the mud is washed from the rig floor. Further. the mud sprays all over the adjacent area and the workmen. making the rig floor dangerously wet and slippery and consequently hazardous for persons working on the rig floor.

To prevent the loss of drilling mud and to prevent having mud on the rig floor. it is well known toprovide a kelly foot valve or mud saver and safety valve on the kelly to close the kelly prior to disconnection from the drill string. thereby preventing the mud from flowing out of the kelly.

A variety of valve assemblies have been designed to serve as mud saver valves. including check valves. flapper valves. float valves. spring loaded plug valves. and collapsable valves. Many of these valve assemblies are actuated by the change in mud pressure within the valve assembly caused by the shutting down of the mud pump. which greatly reduces the mud pressure.

Mud saver valves operated by automatic means may be more expensive than manually actuated valves and the automatic actuation means provides an additional mechanism subject to failure. e.g.. cut out due to the abrasive action of the drilling mud. Manually actuated valves. while avoiding the problems of higher cost and early failure of some automatic valves. require the expenditure of a certain amount of rig time for operation. Assuming 3 minutes of time required for finding the valve handle. inserting the handle in the valve. closing and opening the valve. and removing the handle. perhaps 1.500 minutes of rig time at $2.50 per minute would be so consumed drilling the aforementioned 15.000 foot well.

Automatic and manually operated valves are actuated independently of the tightening of the rotarv shouldered connection between the kelly and the new joint of pipe to be added to the drill string. To make up the connection. tongs are placed on the new joint and a kelly spinner or spinning chain is attached to the kelly. The kelly spinner spins the kelly within the joint until the shoulder of the pin on the kelly mates with the box on the joint. However. the connection still needs to be tightened by replacing the kelly spinner with a second set of tongs. and further tightening the connection. If the connection is not tightened and the new joint is connected to the drill string. it will leak drill mud. Hopefully this leak would be detected prior to running the new joint into the well. Regardless. if the connection is not tightened while the new joint is resting in the mouse hole. much time will be wasted correcting the leak later. This occurs because the opening of an automatic or manually operated valve is in no way related to the final tightening operation of the connection.

It is well known in the art to use a ball-type plug valve captured between spring biased seats sealed within a tubular valve body and having the plug rotated between the open and closed position by means ofa trunnion rotatably mounted on bearings within the tubular body. Examples of the above are shown in US. Pats. Nos.: 3.036.590: 3.384.337; 3.472.270; 3.509.913; Canada Pat. No. 869.692; and the Hydril Kelly Cock manufactured by Hydril Company of Los Angeles. Calif.

US. Pats. Nos.: 2.799.470; 3.036.590; 3.509.913; Canada Pat. No. 869.692 and the Hydril Kelly Cock show a plug valve with a tubular valve body having a lower portion with a box to receive the plug and valve seats and an upper portion with a pin and follower ring 3 threadingly engaged with the box of the lower portion to capture the plug and seats within the assembly.

Rotary shouldered connections on the ends of the tubular valve body for connection with the lower end of the kelly and the upper end of the drill string are shown in U.S. Pats. Nos.: 3.036.590: 3.433.252: and Canada Pat. No. 869.692. This type of connection is used for each connection in a drill string to provide a seal sufficient to withstand the high pressure of the drilling mud. to form a joint strong enough to support the weight of the drill string. to withstand operational bending moments. and to transmit drilling torque. ln the latter regard. the construction is such as to transmit a large por tion of the torque through the frictionally engaged shoulders. eg the unthreaded portion of the pin and box making up the connection. sufficient torque must be applied in making up each connection to insure adequate axial stress in the connection to exert and maintain enough axial pressure on the shoulders to prevent slippage even when the connection is under axial and bending loads tending to separate the shoulders. Torque loads of the order of 50.000 lb.-ft. are normal. To exert such torque. long wrenches or tongs are applied to one or both parts of the connection and force is applied by cable connected to the tongs. one anchored and the other connected to a power winch or cat head. ln disconnecting a drill string connection. torque is similarly applied in the reverse direction. Although the initial breakout torque and the final make up torque are both large. rotary shouldered connections are wholly made up by hand or with light equipment such as a cat line wrapped around the kelly or a kelly spinner connected between the swivel and upper end of the kelly. Similar procedures are used for final breakout rotation. Every time a drill string connection is made up and broken it will be necessary to go through these procedures. The requirement that tongs be used is reflected in the construction of the rotary shouldered connection itself. whose exterior periphery must be soft enough. e.g.. 160 to 240 Brinell hardness and at least below 550 Brinnell. to be tong engageable. In this regard note U.S. Pat. No. 3.067.593 to M. G. McCool. A large diameter tong engageable surface is usually provided just above the pin shoulder and the outer periphery of the box itself forms another tong engageable surface. the box wall thickness being great enough to withstand the application of tongs.

U.S. Pats. Nos. 1.759.060 and 3.472.270 describe a polygonal cross-section trunnion received within hex recesses in the plug for transmission of torque from an actuator rotating the trunnion. Indicators mounted on one end of the trunnion which indicate whether the valve is open or closed are shown in U.S. Pats. Nos. 3.064.940 and 3.284.045.

The above described apparatus is generally well known in the art. However. the means for actuating the trunnion to open and close the valve has proven inconvenient. inadequate and inefficient.

U.S. Pat. No. 3.509.913 Lewis shows an actuator arm mounted on the trunnion and having its other end received by a slot in an actuator piston sleeve whereby the stroke of the piston sleeve pivots the actuator arm. However. the piston sleeve moves axially and does not rotate. ln Moore U.S. Pat. No. 1.759.060 the actuator arm is cammed within the slot of a rotatable actuator sleeve.

Pinions and gears have been used as actuators. Anderson U.S. Pat. No. 3.064.940 shows a manually rotated worm gear rotating a pinion mounted on the trunnion. Kennard U.S. Pat. No. 3.933.252 shows a rack on a piston sleeve engaging a pinion on the trunnion.

Scheid U.S. Pat. No. 1.998.886 describes the use of an annular gear on a throttle valve for an internal combustion engine which rotates a leaf valve by means of pinion and trunnion.

SUMMARY OF THE INVENTION The present invention includes a plug rotatable on a trunnion mounted within a tubular valve body having rotary shouldered connections at each end. The trunnion is pivoted by a dual pinion engaging dual segmented annular gears formed within recesses in a gear sleeve rotatable about the flow axis of the tubular valve body. A tong sleeve is rotatably mounted around the flow axis and is splined to the gear sleeve at one portion and is splined to the tubular valve body at another portion. However. the splined connection between the tong sleeve and tubular valve body has lost motion to permit the trunnion to be rotated so as to close the valve before the splines of the tong sleeve and tubular valve body engage so as to rotate the entire valve assembly.

In the process of adding a section of drill pipe to the drill string. the valve is closed and the kelly disconnected in one motion by the steps of rotating the tong sleeves to close the mud saver valve and rotating the tong sleeve further to disconnect the kelly from the drill string.

The present invention is advantageous over the prior art since the closing of the mud saver valve is not de-- pendent upon a pressure change of the drilling mud within the kelly.

A further advantage is that the valve is closed and the kelly disconnected in one motion requiring one operation. The kelly must be rotated to be disconnected from the drill string anyway. so the closing of the mud saver valve during the same operation is efficient. reliable and time saving.

Another object of the invention is to require the connection between the new joint and kelly to be secure prior to running the new joint into the well. Since the valve is opened during the same operation which tightens the connection between the new joint and valve. the new joint will not be run into the well until the connection is secure because the valve will be closed and no mud will flow if the connection has not been tightened.

Other objects and advantages of the invention will appear from the following description.

BRlEF DESCRIPTlON OF THE DRAWlNGS For a detailed description of a preferred embodiment of the invention. reference will now be made to the accompanying drawings wherein:

FIG. 1 is a schematic of the environment in which the present invention operates:

FIG. 2A is a cross-section of the upper portion of the drilling fluid saver valve;

FIG. 2B is a continuation of the cross-section shown in FlG. ZA showing the lower portion of the drilling fluid saver valve:

FIG. 3 is a cross-section of the drilling fluid saver valve taken at the plane indicated in FIG. 2A;

DESCRIPTION OF THE PREFERRED EMBODlMENT FIG. 1 illustrates generally a drilling fluid saver valve assembly 11) installed in a typical rotary drilling system. The drilling fluid saver valve assembly is shown in detail in F165. 2-5.

Referring now to FIG. 1. a derrick 12 having a derrick floor 14 is shown suspending a drill string 16, pipe joints 18, and 22 being illustrated. within a conductor casing 24 previously installed in an earth bore 26. To support drill string 16 a casing head 28 is mounted on top ofconductor casing 24 with a blowout preventer 30 disposed above casing head 28. The derrick floor 14 is disposed around blowout preventer 30 with a rotary table 32. mounted on derrick floor 14. which is adapted to receive a master bushing 34 to provide the power source to rotate the drill string 16.

As shown in FIG. 1, a set of slips 36 is received in master bushing 34 to suspend drill string 16 within the well during the operation of adding another pipe joint 38. Pipe joint 38 is stored in a mouse hole 40. Mouse hole 40 is a conduit protruding through and supported by the derrick floor and has a closed lower end. Pipe joint 38 rests within mouse hole 40 until it is to be added to drill string 16.

A kelly 42 and the drilling fluid saver assembly 10 are suspended on the derrick 12 above the derrick floor 14 by the draw works including a block and tackle or hoist 44. The hoist 44 includes a crown block (not shown) disposed at the very top of derrick 12 with a traveling block 46 suspended from the crown block by cables 48. The hoist 44 provides a means by which the kelly 42 and valve assembly 10 can be raised and lowered relative to the derrick floor 14.

A swivel 50 is provided with a bail 52 which engages a hook 54 carried by traveling block 46. The kelly is connected at its upper end to swivel 50 by means of a swivel sub 56. Swivel 50 includes the swivel sub 56 which rotates with the kelly 42 and an upper portion 58 rotatably connected to the swivel sub 56 and adapted to remain stationary while the swivel sub 56 rotates with the kelly 42. This permits the swivel 50 to transmit drilling fluid from a stationary hose 60 to kelly 42 while allowing relative rotary motion therebetween.

Kelly 42 is a conduit having a non-circular. polygonal cross-section at its midportion 62 and two circular end portions 64. 66 at each end. The drilling fluid saver valve assembly 10 is connected to the lower end portion 66 of the kelly 42 by means of a rotary shouldered connection formed by a pin 68 projecting from lower end portion 66 and threadingly received by a box 70 disposed in the upper end of valve assembly 10. The combination of the aforedescribed drilling fluid save valve assembly 10 and the kelly 42 constitutes the heart of the present invention since the purpose of the present invention is to prevent the flow of drilling fluid or mud from the kelly 42 when additional joints of pipe such as pipe joint 38 are added to drill string 16.

A kelly bushing 72 is disposed around kelly 42. Kelly bushing 72 has a square cross-section 74 telescopingly and slidingly engageable with the square shaped inner bore 76 of master bushing 34, and a polygonal shaped inner bore 78 telescopingly and slidingly receiving the polygonal periphery 62 of kelly 42. When these connections are engaged. the master bushing 34 transmits torque to the kelly 42. which in turn drives drill string 16.

When it is desired to rotate drill string 16, the kelly 42 is lowered and valve assembly 10 is connected to pipe joint 18 of drill string 16 by means of a second rotary shouldered connection which includes pin 80 projecting from the lower end of valve assembly 10 to be threadingly received by box 82 disposed in the upper end of drill joint 18. The hoist 44 removes the tension on the slips 36 and the slips 36 are removed. The drill string 16 is then lowered until kelly bushing 72 is received in the bore 76 of master bushing 34. Thereupon the rotary table 32 can rotate the drill string 16 through master bushing 34. kelly bushing 72. the kelly 42 and drilling can proceed.

In a rotary drilling system a drilling fluid or mud continually passes through the system during the drilling operation. The mud is pumped by mud pump 90. which is driven by drilling motor 92, from a surface reservoir or mud pit 94 and through

pipes

96, 98 to the hose 60 previously described as attached to swivel 50. The mud then passes through swivel 50 and down the common flow bore of the kelly 42. valve assembly 10 and drill string 16 to a rotary bit (not shown) at the bottom of the well bore 26. The mud is ejected at high velocity through a number of ports extending through the wall of the bit and is circulated up the annulus 100 between the casing 24 and drill string 16. The mud passes from annulus 100 via side port 102 in casing head 28 and through pipe 104 and back to mud pit 94 for recirculation.

Referring now to FIGS. 2-5 for a detailed description of the drilling fluid saver valve assembly 10. there is shown in FIGS. 2A and 28 a cross-section of the complete assembly 10 with FIG. 2A illustrating the upper portion thereof and FIG. 2B illustrating the lower portion. Valve assembly 10 includes a tubular body having an upper body portion 112 and a lower body portion 114. The upper body portion 112 provides the flow inlet for flow bore 116 of the tubular body 110 and the lower body portion 114 provides the flow outlet.

The upper body portion 112 includes box 70 for threadingly receiving pin 68 of kelly 42 to form a rotary shouldered connection. and the lower body portion 114 includes pin 80 adapted for threaded engagement with box 82 disposed on pipe joint 18 to form a second rotary shouldered connection. The rotary shouldered connections described in patent application Ser. No. 73.959 filed Sept. 21. 1970. could be used for the connections described above.

A valve nest 118 is disposed in the upper end of the lower body portion 114 opposite pin 80 and includes a series of

counterbores

120, 122, 124 and 126. Counterbore provides internal threads 128 at its upper end to form box 130.

A valve core 132 is adapted to be received by valve nest 118. and includes two identical valve seats 134 and a plug type stopper 136. Valve seats 134 have a reduced outer diameter neck 137 creating an annular shoulder 138. The end of seats 134 adjacent neck 137 has an inner frusto-conical surface 140 and the opposite end has a conterbore 142. An inner frusto-conical surface 144 is disposed at the base of counterbore 142. An outer frusto-conical surface 146 is disposed on the outer lip of the end opposite neck 136 of seats 134, and an annular pressure sealing surface 148 is disposed on the inner lip of that same end for engagement with stopper 136.

Stopper 136 is generally spherical with a flow bore 150 through the middle. the same size as flow bore 116. The axis of bore 150 is perpendicular to the rotational axis of stopper 136. The interfaces of the bearing surfaces 152, 154 of counterbore 122 and stopper 136. respectively. are planes parallel to the flow axis and perpendicular to the axis of rotation of the stopper 136. The remaining spherical faces 156 of stopper 136 have the same general curvature as counterbore 122 so as to slidingly fit therein when the stopper 136 is inserted into counterbore 122 and rotated therein.

In the assembled position. an annularly bowed flat spring 158 is inserted within the valve nest 118 as shown. with spring 158 having generally the same mean diameter as upwardly facing annular shoulder 160 created by counterbore 126. The neck 137 of the lower seat 134, having a slip fit with counterbore 126, is received by nest 118 with counterbore 124 providing substantial lateral clearance. Stopper 136 is inserted into nest 118 with bearing surfaces 152, 154 in a mating position. The upper seat 134 is then received within nest 118.

The upper tubular body portion 112 has a pin 162 on its lower end forming an outer annular downwardly facing flange 164 and an inner frusto-conical shoulder 166. A counterbore 168 is disposed within pin 162 for receiving the neck 137 of upper seat 134 and another annularly bowed flat spring 170. Pin 162 has exterior threads 172 threadingly engaging the interior threads 128 of box 130 as pin 162 is received by nest 118 and box 130. Spring 170 engages the downwardly facing annular shoulder 174 created by counterbore 168, and counterbore 168 receives the neck 137 of upper seat 134 as pin 162 is threadingly received by box 130.

Springs

158 and 170, seating on

shoulders

160 and 174, urge the annular pressure sealing surfaces 148 of seats 134 into annular engagement with curved surfaces 156 of stopper 136. Inner frusto-conical shoulder 166 of upper body portion 112 mates with a correlating frustoconical surface 176. forming the extreme end 177 of lower body portion 114, thereby limiting the reception of pin 162 within box 130.

A series of O-rings are used to seal the flow bore 116 from leakage due to the high pressure placed on the drilling fluid. O-rings 178 are disposed in external annular grooves 180 above and below threads 128 to sealingly engage the smooth sealing surface 182 of counterbore 120. The mating of shoulder 166 and end 177 causes O-rings 178 to tightly engage surface 183. rings 184 are located in annular grooves 186 in the exteriorsurface of necks 137 of seats 134 to sealingly engage the smooth sealing surfaces 188, 190 of

counterbore

126 and 168, respectively.

The drive train for rotating stopper 136 includes a trunnion 200, gear sleeves 202, and actuator sleeve 204 as shown in FIG. 3.

The trunnion 200 rotates stopper 136 between an open position. where the flow bore 150 aligns with flow bore 116, and a closed position, where flow bores 150 and 116 are not aligned. Corresponding polygonal recesses 206 in bearing surfaces 154 receive mating po- Iygonal cross-sectioned pins 208 disposed on the interior ends of trunnion 200. Trunnion 200 is rotatably mounted in bearing holes 210 passing through the bearing surfaces 152 of counterbore 122. O-rings 212, disposed within annular grooves 214 in trunnion 200, sealingly engage the smooth surfaces 215 of bearing holes 210 to prevent mud from escaping.

Referring now to FIG. 4. gear sleeve 202 is rotatably mounted about the upper part of lower body portion 114 and has

windows

216, 218 which receive pinions 220 disposed on the exterior ends of trunnion 200. Crown gear teeth are cut in the upper side of window 216 at 222 and in the lower side of window 218 at 224, and mesh with pinions 220 such that. as gear sleeve 202 is rotated about the axis of flow bore 116, trunnion 200 rotates stopper 136. The engagement of the upper edge of one pinion 220 by the upper side of window 216 and the engagement of the lower edge of other pinion 220 by the lower side of window 218 prevent any torque from being placed on trunnion 200 and permit a more even distribution of the forces on trunnion 200.

Referring to FIG. 2B. actuator sleeve 204 is rotatably mounted about the mid section of lower body portion 114 and is exteriorly splined at its upper end at 226 to interior splines 228 on the lower end of gear sleeve 202. Therefore. the stopper 136 will move between the open and closed position when the actuator sleeve 204 is manually rotated with tongs or a wrench.

A housing sleeve 230, having a counterbore 232 at its lower portion. slips over the upper end of lower body portion 114 and encloses gear sleeve 202 within counterbore 232. The extreme end of housing sleeve 230 circumscribes the splines at 226 and a further upper part of actuator sleeve 204. Housing sleeve 230 is mounted to the lower body portion 114 by means of a threaded pin or screw plug 234 protruding into a small bore 236 in the upper end of lower body portion 114. The upper extreme rod 238 of housing sleeve 230 abuts downwardly facing flange 164 of upper body portion 112. O-ring 240, disposed in annular groove 242 on the upper interior surface of housing sleeve 230, sealingly engages the smooth sealing surface 244 of the upper end of lower body portion 114. Dual O-rings 246 are disposed in annular grooves 248 in the lower interior surface 250 of conterbore 232 to sealingly engage the smooth sealing peripheral surface 252 of actuator sleeve 204.

Housing sleeve 230 also provides support for pinions 220. Plugs 254 are received by recesses 256 in the exterior ends of trunnion 200 and extend through ports 258 in housing sleeve 230. Plugs 254 are attached to trunnion 200 by bolts 260 countersunk into plugs 254 and threaded into tapped bores 262 in the ends of trunnion 200. O-rings 264, received by annular grooves 266 disposed around plugs 254, sealingly engage the smooth sealing surface of ports 254 to prevent leakage. As shown in FIG. 4, an indicator 268 affixed to bolt 260 indicates whether the valve is open or closed.

Referring now to FIGS. 2B and 5. actuator sleeve 204 has splines 270 housed within counterbore 272 disposed in the lower end of sleeve 204, and is splined at 274 to the periphery of the lower body portion 114. The segmented channels 276, as best shown in FIG. 5, are much larger than the correlating splines 278 disposed on reduced diameter portion 288 of body portion 114. Channels 276 therefore permit actuator sleeve 204 to be rotated a sufficient distance to cause stopper 136 to be rotated to the closed position before the side shoulders 280 of channels 276 engage splines 278 and cause tubular body 110 to rotate. This lost motion between the actuator sleeve 204 and lower body portion permits the valve to be closed and the valve as sembly 10 to be disconnected from the pipe joint 18 in one continuous rotation of the actuator sleeve 204. Bearing rings 282 are disposed between the lower end of actuator sleeve 204 and upwardly facing shoulder 284 created by reduced diameter portion 286 of lower body portion 114.

In the operation of the present invention. when drilling has progressed to where the kelly 42 has moved down to the point in which the sub 64 is right on top of the kelly bushing 72. it becomes necessary to add another piece of drill pipe such as pipe joint 38 shown stored in mouse hole 40 in FIG. 1. The drill string 16 is lifted by the hoise 44 until the kelly bushing 72 clears the master bushing 34 and slips 36 are inserted to suspend the drill string 16 as shown in FIG. 1. The motor 92 is stopped. thereby shutting down the mud pump 90. At this time. the pressure in drill string 16, as indicated by gage 300, should drop to substantially zero. If it does not. bleeder valve 302 is opened to bleed off the residual pressure.

To breakout and disconnect the connection between the drill string 16 and valve assembly 10. a breakout torque is applied to the connection by clamping tongs or a wrench (not shown) to the uppermost pipe joint 18 of drill string 16 with an anchor cable (not shown) affixed to derrick l2, and by attaching power tongs to the actuator sleeve 204 with a cable (not shown) extending from the power tongs to a cat-line (not shown). The cat-line pulls on the cable to cause the power tongs to rotate the actuator sleeve 204.

The first partial rotation closes the valve. during which time the lost motion between the splines of actuator sleeve 204 and body portion 114 is expended. and further rotation of actuator sleeve 204 causes the drilling fluid saver valve assembly 10 and kelly 42 to rotate thereby unthreading pin 80 from box 82 on pipe section 18.

Following the initial breakout of the connection using the power tongs. the connection may be completely disconnected by anchoring the tongs attached to actuator sleeve 204, removing the tongs on joint 18, and turning on the rotary table 32. Rotary table 32 rotates joint 18 because of slips 36 and master bushing 34, thereby disconnecting the connection. As the kelly 42 and assembly 10 are lifted from drill string 16, no mud flows out since the valve is closed.

The kelly 42 and assembly 10 are then pushed over to one side of the derrick l2 and aligned with box 304 of pipe joint 38 in mouse hole 40. Tongs (not shown) are clamped to joint 38 with an anchor cable (not shown) being attached to derrick 12. A spinning claim or kelly spinner (not shown) is positioned around valve assembly 10. A forked cable is used by wrapping the shorter branch around valve assembly 10 and tying the longer branch to the tongs such that. as the shorter branch of the cable is wound on a cat-line. the kelly is threaded into joint 38. When all the slack of the longer branch of the cable has been taken up. pin 80 and box 304 are almost completely engaged. The tongs attached to the longer branch are then attached to actuator sleeve 204. Force is then applied to the longer branch, rotating actuator sleeve 204 in a direction opposite to that of the breakout operation first opening the valve again, and then finally tightening pin 80 within box 304. The mud previously trapped in kelly 42 and assembly 10 then flows through pipe joint 38 and into mouse hole 40, which has an overflow 306 to remove excess accumulated mud. Because of the frictional drag within the drive train of valve assembly 10, a torque sufficient to initially threadingly engage pin within box 304 can be applied without causing actuator sleeve 204 to open the valve. Only when the connection is tightened will a large enough torque be placed on actuator sleeve 204 to cause the drive train to actuate the valve.

Pipe joint 38 is then lifted out of mouse hole 40, and pin 308 on joint 38 is stabbed and screwed tight into box 82 ofjoint 18. The pump motor 92 is then restarted restoring circulation. and the newly added joint 38 and its connections are checked for leaks. If there are no leaks. the joint 38 is lowered in the hole and kelly 42 is lowered until kelly bushing 72 engages recess 76 in master bushing 34. Drilling is then resumed.

After rising the prior art valves. the connection between the kelly 42 and new joint 38 was not finally tightened until the joint 38 was connected to the uppermost pipe joint 18 of drilling string 16. Upon starting the mud pump again. the prior art valves would permit the circulation of mud through the system causing a leak at the connection. lf the lead were detected. the connection could not be tightened until the joint had been run into the well sufficiently for the connection to reach a workable level. This would be difficult because the joint would have to be run into the well without mud circulation due to the leak. If the lead through the unsecured connection was not detected. the added joint 38 could be lowered in the well before the leak eventually was discovered. By making the tightening operation synonymous with the opening of the valve. this type of error could not be made.

In addition to the special function heretofore described of the drilling fluid saver valve assembly so as a mud saver valve, the assembly l0 also serves as a conventional safety valve. The stopper 136 van be rotated to lose the valve assembly 10 and prevent drilling fluid from backing up on the drill string 16.

While a preferred embodiment of the invention has been shown and described. modification thereof can be made by one skilled in the art without departing from the spirit of the invention.

I claim:

1. In the process of adding a section of drill pipe to a rotary drill string suspended in a well bore from a kelly by means including a drilling fluid saver valve assembly having a rotatable sleeve to open and close the drilling fluid saver valve. the method comprising the steps of:

rotating the sleeve to close the drilling fluid saver valve. and

rotating further the sleeve to disconnect the kelly from the drill string.

2. Method according to claim 1 wherein the valve is connected to the uppermost drill pipe in the drill string by a rotary shouldered connection and the rotation of the sleeve is effected by connecting tongs to the sleeve and pulling on the tongs with sufficient force to not only close the valve but break out the rotary shouldered connection following which the valve and kelly are suitably rotated to completely unscrew the rotary shouldered connection.

1 l 3. Method according to claim 1 followed by the further steps of:

inserting a portion of the drilling fluid saver valve assembly into a joint of drill pipe. rotating the sleeve to openthe drilling fluid saver valve and rotating further the sleeve to connect the drilling fluid saver valve assembly to the joint of drill pipe. 4. Method according to claim 3 wherein the valve is connected to the uppermost drill pipe in the drill string by a rotary shouldered connection and when the portion of the drilling fluid saver valve is inserted into the the upper end of the drill string.

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,377,5 9 DATED April 15, 1975 V 1 Mason Rawleigh Litchfield It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the Front Page, Item 73, cancel "Mich." and substitute "Tex."

Signed and Salad this r r -th' [SEAL] D f March 1976 Attest:

RUTH C. MASON Arresting Officer C. MARSHALL DANN Commissioner oflatents and Trademarks

Claims

1. In the process of adding a section of drill pipe to a rotary drill string suspended in a well bore from a kelly by means including a drilling fluid saver valve assembly having a rotatable sleeve to open and close the drilling fluid saver valve, the method comprising the steps of: rotating the sleeve to close the drilling fluid saver valve, and rotating further the sleeve to disconnect the kelly from the drill string.

3. Method according to claim 1 followed by the further steps of: inserting a portion of the drilling fluid saver valve assembly into a joint of drill pipe, rotating the sleeve to open the drilling fluid saver valve, and rotating further the sleeve to connect the drilling fluid saver valve assembly to the joint of drill pipe.

4. Method according to claim 3 wherein the valve is connected to the uppermost drill pipe in the drill string by a rotary shouldered connection and when the portion of the drilling fluid saver valve is inserted into the joint of drill pipe it is mAde up therein hand tight by rotating the kelly and thereafter tongs are connected to the sleeve and a pull applied to the tongs to effect such rotation of the sleeve sufficient to open the valve and make up the rotary shouldered connection.

5. Method according to claim 3 followed by the further steps of: elevating the joint of drill pipe until the lower end is above the upper end of the drill string, and connecting the lower end of said joint of drill pipe to the upper end of the drill string.