GB2073288A - Drill pipe tester valve - Google Patents

Abstract

A drill pipe tester valve for installation in a pipe string has a housing having a first end adapted to be connected to a well test string, which housing has a flow passage (90) therethrough. A spherical valve member (92) is disposed in the flow passage of the housing. Lugs (118) are provided for engaging the spherical valve member and rotating the spherical valve member between open and closed positions wherein the flow passage of the housing is open and closed, respectively, as the spherical valve member is moved axially relative to the housing. A lower valve member seat structure (130) has a downward facing surface (132) supportably engaged by an upward facing surface (134) of the housing when the spherical valve member is in its said closed position. This permits downward forces exerted upon the spherical valve member in its said closed position due to fluid pressure in the well test string of drill pipe above the spherical valve member, to be transmitted substantially entirely to the housing through the engagement of the downward facing surface of the lower valve seat structure and the upward facing surface of the housing. <IMAGE>

Description

SPECIFICATION Drill pipe tester valve This invention relates generally to drill pipe tester valves, and more particularly, but not by way of limitation, to drill pipe tester valves designed to be used above a formation tester valve in a well test string.

During the course of drilling an oil well, one operation which is often performed is to lower a testing string into the well to test the production capabilities of the hydrocarbonproducing underground formations intersected by the well. This testing is accomplished by lowering a string of pipe, commonly referred to as drill pipe, into the well with a formation tester valve attached to the lower end of the string of pipe and oriented in a closed position, and with a packer attached below the formation tester valve. This string of pipe with the attached testing equipment is generally referred to as a well test string.

Once the test string is lowered to the desired final position, the packer means is set to seal off the annulus between the test string and a well casing, and the formation tester valve is opened to allow the underground formation to produce through the test string.

During the lowering of the test string into the well, it is desirable to be able to pressure test the string of drill pipe periodically so as to determine whether there is any leakage at the joints between successive stands of drill pipe.

To accomplish this drill pipe pressure testing, the string of drill pipe is filled with a fluid and the lowering of the pipe is periodically stopped. When the lowering of the pipe is stopped, the fluid in the string of drill pipe is pressurized to determine whether there are any leaks in the drill pipe above the formation tester valve.

With the apparatus and methods generally used in the prior art for testing the drill pipe as it is lowered into the well, the fluid in the string of pipe is generally contained within the drill pipe only by the closure of the formation tester valve. In other words, the pressure exerted on the fluid in the drill pipe is also exerted against the closed formation tester valve.

This prior art arrangement has often been utilized with a formation tester valve similar to that shown in U.S. Patent No. 3,856,085 to Holden et al. The Holden et al formation tester valve has a spherical valve member contained between upper and lower valve member seats.

The Holden et al formation tester valve is shown only schematically in U.S. Patent No.

3,856,085, and the details of the mounting of the spherical valve member within the housing of the valve are not there-shown. The actual formation tester valve constructed according to the principles of Holden et al U.S.

Patent No. 3,856,085 has the upper valve seat for the spherical valve member suspended from an inner mandrel which is hung off an annular shoulder of the outer valve housing, in a manner similar to that shown in U.S. Patent No. Re. 29,471 to Giroux. The lower valve seat is connected to the upper valve seat by a plurality of C-clamps spanning around the spherical valve member. The lower valve seat member of the Holden et al formation tester valve does not, therefore, engage any supporting portions of the valve housing.

The spherical valve member of the Holden et al formation tester valve is held in place within the housing so as to prevent axial movement of the spherical valve member relative to the housing, and is engaged by eccentric lugs mounted on a sliding member which does move axially relative to the housing so that upon axial movement of the lugs relative to the housing, the spherical valve member is rotated relative to the housing to open and close the valve.

When pressure testing drill pipe located above a formation tester valve like that of Holden et al. experience has shown that excessive pressure exerted upon the top surface of the spherical valve member of the Holden et al apparatus, causes the spherical valve member to exert a downward force on the eccentric lugs thereby shearing the eccentric lugs off their carrying member. This severely limits the maximum pressure which may be exerted upon the fluid within the drill pipe to pressure test the same, and it is particularly a significant problem in very deep wells where the mere hydrostatic pressure of the fluid within the drill pipe is relatively high. It has been determined that the maximum differential pressure which can safely be carried by the Holden et al valve is about 5000 psi.

Another prior art valve having a spherical valve member which does not move axially relative to its housing is the subsea test valve shown in U.S. Patent No. 4,116,272 to Barrington.

Other prior art valves having a spherical valve member which does move axially relative to the housing are shown in U.S. Patent No. 4,064,937 to Barrington; U.S. Patent No. 3,568,715 to Taylor, Jr.; U.S. Patent No. Re. 27,464 to Taylor, Jr.; U.S. Patent No. 4,009,753 to McGill, et al; and U.S.

Patent No. 3,967,647 to Young.

The present invention provides a drill pipe tester valve which is especially suited to be run in the well test string directly above a formation tester valve such as that of Holden et al U.S. Patent No. 3,856,085. The drill pipe tester valve of the present invention reduces or overcomes the prior art difficulties encountered due to pressure testing directly against the formation tester valve, by having a lower valve seat which is supportably engaged by the valve housing, so as to prevent down ward forces from being exerted upon the eccentric actuating lugs thereof when the fluid in the drill pipe is pressurized, thereby preventing the shearing of those lugs on the drill pipe tester valve. Drill pipe tester valves of the present invention can be constructed to withstand differential pressures up to 1 G,OOO psi.

Additionally, the drill pipe tester valve of the present invention can have an automatic fill-up feature which automatically allows the drill pipe located above the drill pipe tester valve to fill with well fluid as the test string is lowered into the well.

According to the invention, there is provided a pipe tester valve for installation in a pipe string, comprising: a housing having a first end adapted to be connected to a string of pipe, and having a flow passage therethrough; a spherical valve member disposed in said flow passage of said housing; lug means for engaging said spherical valve member and rotating said spherical valve member between open and closed positions wherein said flow passage is open and closed, respectively; and lower valve seat means for sealingly engaging a lower surface of said spherical valve member, said lower valve seat means having a downward facing surface supportably engaged by an upward facing surface of said housing when said spherical valve member is in its said closed position, so that downward forces exerted (in use) upon said spherical valve member in its said closed position due to fluid pressure in said string of pipe above said spherical valve member are transmitted substantially entirely to said housing through said engagement of said downward facing surface and said upward facing surface.

The invention further provides a pipe tester valve for installation in a pipe string, comprising: a housing having a first end adapted to be connected to a string of pipe, and having a flow passage therethrough; a spherical valve member disposed in said flow passage of said housing; lug means, attached to said housing, for engaging said spherical valve member and rotating said spherical valve member between open and closed positions wherein said flow passage is open and closed, respectively, as said spherical valve member is moved axially relative to said housing and said lug means; and moving means for moving said spherical valve member axially relative to said housing between its said open and closed positions, said moving means including lower valve member seat means having a downward facing surface supportably engaged by an upward facing surface of said housing when said spherical valve member is in its said closed position, so that downward forces exerted on said spherical valve rnember in its said closed position (in use) due to fluid pressure in said string of pipe above said spherical valve member are transmitted substantially entirely to said housing through said engagement of said downward facing surface and said upward facing surface.

The valves of the invention may include a latch means for latching the spherical valve member in its said closed position as said string of pipe and drill pipe tester valve are lowered into the well. The latch means releases the spherical valve member and aliows it to move to its open position during the formation testing procedures. After the formation testing procedures are completed, or at any other time when the weight of the well test springs is picked up, the latch means provides a means for moving the spherical valve member back to its closed position thereby providing a safety valve feature in addition to the drill pipe testing feature of the drill pipe tester valve of the present invention.

The invention also includes a well test string incorporating a pipe tester valve of the invention.

The invention further includes a method of pressure testing a string of pipe utilising a pipe tester valve of the invention.

The invention also includes a method of pressure testing a string of pipe as said string of pipe is lowered into a well, said method comprising the steps of: providing on a lower end of said string of pipe a pipe tester valve including a housing having a flow passage therethrough, a spherical valve member disposed in said flow passage of said housing, the lower valve seat means sealingly engaging a lower surface of said spherical valve member, said lower valve seat means having a downward facing surface supportably engaged by an upward facing surface of said housing when said spherical valve member is in a closed position; lowering said string of pipe into said well; filling said string of pipe above said spherical valve member with a fluid; stopping said lowering of said string of pipe periodically; pressure testing said string of pipe while said lowering of said string of pipe is stopped and said spherical valve member is in its said closed position, so that successive portions of said string of pipe are pressure tested periodically as said string of pipe is lowered into said well; and supporting said lower valve seat means, against a downward force exerted on said spherical valve member by said pressure testing of said string of pipe, from said housing by said engagement of said downward facing surface of said lower valve seat means and said upward facing surface of said housing.

A drill pipe tester valve of the prevent invention preferably has a housing having a first end adapted to be connected to the string of drill pipe, which housing has a flow passage therethrough. The spherical valve member is disposed in the flow passage of the housing. Preferably, lug means are attached to the housing for engaging the spherical valve member and rotating the spherical valve member between open and closed positions wherein the flow passage of the housing is open and closed, respectively, as the spherical valve member is moved axially relative to the housing and the lug means.

Moving means may be provided for moving the spherical valve member axially relative to the housing between its said open and closed positions, which moving means preferably includes a lower valve member seat means having a downward facing surface supportably engaged by an upward facing surface of the housing when the spherical valve member is in its said closed position. This permits downward forces exerted upon the spherical valve member in its said closed position due to fluid pressure in the string of drill pipe above the spherical valve member, to be transmitted substantially entirely to the housing through the engagement of the downward facing surface of the lower valve seat means and the upward facing surface of the housing.

A resilient spring means may also be provided for resiliently urging the spherical valve member downward relative to the housing toward its said closed position, which resilient spring means provides an automatic means for allowing the spherical valve member to be moved upward by fluid pressure from the annulus between the test string and a well casing as the test string is lowered into the well casing, thereby permitting said well fluid to pass through the spherical valve member into the string of drill pipe located above the spherical valve member as the test string is lowered into the well.

In order that the invention may be more fully understood, reference is made to the accompanying drawings, in which: Figure 1 shows a schematic view of a well test string in place within an offshore well; Figures 2A-2E show a half-section elevation view of one embodiment of drill pipe tester valve of the present invention, given by way of illustration only; Figure 3 shows a laid-out view of one embodiment of J-slot and lug of the drill pipe tester valve of Figs. 2A-2E; and Figures 4A-4E show a half-section elevation view of another embodiment of the drill pipe tester valve of the present invention providing an automatic fill-up feature.

It is appropriate at this point to provide a description of the environment in which the present invention is used. During the course of drilling an oil well, the borehole is filled with a fluid known as drilling fluid or drilling mud. One of the purposes of this drilling fluid is to contain in intersected formations any formation fluid which may be found there. To contain these formation fluids the drilling mud is weighted with various additives so that the hydrostatic pressure of the mud at the formation depth is sufficient to maintain the formation fluid within the formation without allowing it to escape the borehole.

When it is desired to test the production capabilities of the formation, a testing string is lowered into the borehole to the formation depth and the formation fluid is allowed to flow into the string in a controlled testing program.

Sometimes, lower pressure is maintained in the interior of the testing string as it is lowered into the borehole. This is usually done by keeping a formation tester valve in the closed position near the lower end of the testing string. When the testing depth is reached, a packer is set to seal the borehole thus closing in the formation from the hydrostatic pressure of the drilling fluid in the well annulus. The formation tester valve at the lower end of the testing string is ihen opened and the formation fluid, free from the restraining pressure of the drilling fuid, can flow into the interior of the testing string.

At other times the conditions are such that is desirable to fill the testing string above the formation tester valve with liquid as the testing string is lowered into the well. This may be for the purpose of equalizing the hydrostatic pressure head across the walls of the test string to prevent inward collapse of the pipe and/or may be for the purpose of permitting pressure testing of the test string as it is lowered into the well.

The well testing program includes periods of formation flow and periods when the formation is closed in. Pressure recordings are taken throughout the program for later analysis to determine the production capability of the formation. If desired, a sample of the formation fluid may be caught in a suitable sample chamber.

At the end of the well testing program, a circulation valve in the test string is opened, formation fluid in the testing string is circulated out, the packer is released, and the testing string is withdrawn.

A typical arrangement for conducting a drill stem test offshore is shown in Fig. 1. Such an arrangement would include a floating work station 1 0 stationed over a submerged work site 12. The well comprises a well bore 14 typically lined with a casing string 1 6 extending from the work site 1 2 to a submerged formation 1 8. The casing string 1 6 includes a plurality of perforations at its lower end which provide communication between the formation 1 8 and the interior of the well bore 20.

At the submerged well site 1 2 is located the well head installation 22 which includes blowout preventor mechanisms. A marine conductor 24 extends from the well head installation to the floating work station 10. The floating work station 1 0 includes a work deck 26 which supports a derrick 28. The derrick 28 supports a hoisting means 30. A well head closure 32 is provided at the upper end of marine conductor 24. The well head closure 32 allows for lomséring into the marine conductor and into the well bore 14 a formation testing string 34 which is raised and lowered in the well by hoisting means 30.

A supply conduit 36 is provided which extends from a hydraulic pump 38 on the deck 26 of the floating station 10 and ex- tends to the well head installation 22 at a point below the blowout preventors to allow the pressurizing of the well annulus 40 surrounding the test string 34.

The testing string 34 includes an upper conduit string portion a2 extending from the work site 1 2 to the well head installation 22.

A hydraulically operated conduit string test tree 44 is located at the end of the upper conduit string 42 and is landed in the well head installation 22 to thus support the lower portion of the lorEnation testing string. The lower portion of the formation testing string extends from the test tree 44 to the formation 1 8. A packer mechanism 46 isolates the formation 1 8 from fluids in the well annulus 40.A perforated tail piece 48 is provided at the lower end of the testing string 34 to allow fluid communication between the formation 1 8 and the interior of the tubular formation testing string 34.

The lower portion of the formation testing string 34 further includes intermediate conduit portion 50 and torque transmitting pressure and volume balanced slip joint means 52. An intermediate conduit portion 54 is provided for imparung packer setting weight to the packer mechanism 46 at the lower end of the string.

It is many times desirable to place near the lower end of the testing string a conventional circulation valve 56 which may be opened by rotation or reciprocation of the testing string or a combination of both or by the dropping of a weighted bar in the interior of the testing string 10. Below circulating valve 56 there may be located a combination sampler valve section and reverse circulation valve 58, such as that shown in U.S. Patent No. 4,064,937 to Barrington and assigned to the assignee of the present invention.

Also near the lower end ow the formation testing string 34 is located formation tester valve 60 which is preferably a tester valve of the annulus pressure operated type similar to that disclosed in U.S. Patent No. 3,856,085 to Holden et al. Immediately above the formation tester valve 60 is located the drill pipe tester valve 62 of the present invention.

A pressure. reccsrding device 64 is located below the formation tester valve 60. The pressure recording device 64 is preferably one which provides a iu310pening passageway through the center of the pressure recorder to provide a full opening passageway through the entire length of the formation testing string.

it may be desirable to add additional formation testing apparatus in the testing string 34.

For instance, where it is feared that the testing string 34 may become stuck in the borehole 14 it is desirable to add a jar mechanism between the pressure recorder 64 and the packer assembly 46. The jar mechanism is used to impart blows to the testing string to assist in jarring a stuck testing string loose from the borehole in the event that the testing string should become stuck. Additionally, it may be desirable to add a safety joint be tween the jar and the packer mechanism 46.

Such a safety joint would allow for the testing string 34 to be disconnected from the packer assembly 46 in the event that the jarring mechanism was unable to free a stuck formation testing string.

The location of the pressure recording device may be varied as desired. For instance, ihe pressure recorder may be located below the perforated tail piece 48 in a suitable pressure recorder anchor shoe running case.

In addition, a second pressure recorder may be run imrnecliately above the formation tester valve 60 to provide further data to assist in evaluating the well.

Referring now to Figs. 2A-2E, a half-section elevation view is thereshown of the drill pips tester valve 62 of the present invention.

The drill pipe tester valve 62 includes a housing 66 including an upper adapter 68, a first cylindrical valve casing portion 70, a middle adapter portion 72, and a second valve casing portion 74.

The upper adapter 68 and first cylindrical valve casing portion 70 may generally be referred to as an upper housing portion 76, and the middle adapter portion 72 and second valve casing 74 may collectively be referried to as a lower housing portion 78.

An upper end 80 of lower housing portion 78 is received within a lower end 82 of upper housing portion 71S, and attached thereto at threaded connection 84.

Grousing 66 has an upper end 86 adapted to be connected to a string of pipe of formation testing string 34 (See Fig. 1) by means of an internally threaded connection 88. In this manner tne entire weight ou the portions of the test string 34 located below connection 88 is carried by the housing 66. Housing 66 has a flow passage 98 disposed axially therethrough.

Disposed within flow passage 90 is a spher ical valve member 92 which has a valve bore 94 therethrough. Spherical valve member 92 is shown in Fig. 23 in its closed position closing the flow passage 90.

The spherical valve member 92 has its upper surface 96 seated against an upper valve seat 98 and has its lower surface 100 seated against a lower valve seat 1 02.

The upper valve seat 93 is disposed in an upper valve seat carrier 104 and the lower valve seat 102 is disposed in a lower valve seat carrier 106. The upper and lower valve seat carriers 104 and 106 are connected together by a plurality of C-clamps, such as the clamp 108, two ends of which are shown in Fig. 2B. It will be understood that the Cclamp 108 is a continuous member between the two ends which are illustrated in Fig. 2B, and it therefore holds the valve seat carriers 104 and 106 together about spherical valve member 92.

A positioning mandrel or guide mandrel 109 has its lower end attached to upper valve seat carrier 104 at threaded connection 110 and has an upper end 11 2 closely received within a cylindrical inner surface 11 4 of upper adapter 68. An annular seal 11 6 is disposed between positioning mandrel 108 and inner cylindrical surface 11 4.

An eccentric lug 11 8 is attached to a lug carrying mandrel 1 20 which is received within valve casing 70 and engaged at its upper and lower ends 1 22 and 124, respectively, by upper adapter 68 and by upper end 80 of middle adapter 72 so that eccentric lug 11 3 is held in a fixed position relative to housing 66.

The eccentric lug 11 8 engages an eccentric hole 1 26 disposed radially through a wall of spherical valve member 92.

A second eccentric lug (not shown) similar to lug 11 8 also engages another eccentric hole (not shown) of spherical valve member 92 in a manner similar to that shown in Figs.

4A-4C of U.S. Patent No. 3,856,085 to Holden et al., the details of which are incorporated herein by reference.

It will be appreciated that the representation of the eccentric lug 11 8 and mandrel 120, and of the C-clamp 108 are rather schematically shown in Fig. 2B, for purposes of convenient illustration, and that in a true sectional view of the drill pipe tester valve, both the lug 11 8 and the C-clamp 108 would not be shown in the same sectional view since the two are radially spaced.

When the spherical valve member 92 is moved axially relative to housing 66, in a manner which will be further described below, the engagement of lug 11 8 with eccentric hole 1 26 causes causes the spherical valve member 92 to be rotated relative to housing 66 between open and closed positions wherein flow passage 90 is opened and closed, respectively. The spherical valve member 92 is shown in Fig. 2B in its closed position. By movement of spherical valve member 92 axially upward relative to housing 66 from the position shown in Fig. 2B, the spherical valve member 92 is caused to be rotated toward an open position wherein the valve bore 94 is aligned with the flow passage 90 of housing 66 so as to permit flow of fluid through the flow passage 90 from one end to the other of housing 66.

Moving means generally designated by the numeral 1 28 are provided for moving spherical valve member 92 axially relative to housing 66. The moving means 128 may be considered as including the lower valve seat carrier 106 and the lower valve seat 102 which may be collectively referred to as a lower valve seat means 1 30. The lower valve seat means 1 30 is also sometimes referred to in the following description as a lower valve member seat means.

The lower valve seat carrier 106 includes an annular downward facing surface 1 32 which is supportably engaged by an upward facing surface 1 34 of upper end 80 of middle adapter 72 of housing 66 when spherical valve member 92 is in its closed position as illustrated in Fig. 28. This arrangement permits downward forces exerted upon spherical valve member 92 when in its closed position, due to fluid pressure in the test string 34 above spherical valve member 92, to be transmitted substantially entirely to housing 66 through said engagement of downward facing surface 1 32 and upward facing surface 1 34.

This provides a very strong support below the spherical valve member 92 so that when the very high fluid pressures from testing of drill pipe are exerted upon the upper surface 96 of spherical valve member 92, those pressures will be transmitted directly to the housing 66 rather than being transmitted to lugs 11 8 and creating problems of failure of those lugs as was described above with regard to use of prior art devices such as that of Holden, et al Patent No. 3,856,085.

In the disclosed embodiment the downward facing surface 1 32 is specifically located upon the lower valve seat carrier 106. It may, however, be generally said to be located upon the lower valve seat means 1 30, and it will be understood that the physical arrangement of the lower valve seat means 1 30 could be modified to include additional elements or to integrate seat 102 and seat carrier 106 into a single element. All that is important is that a downward facing surface, such as surface 132, be located upon a structure which structurally supports the spherical valve member 92 from below. Such structure may generally be referred to as a lower valve seat means.

The moving means 1 28 also includes a moving mandrel means 1 36 which is comprised of an upper moving mandrel portion 1 38 and a lower moving mandrel portion 140.

The upper moving mandrel portion 1 38 and an upper part of the lower moving mandrel portion 1 40 are reciprocably received within the lower end of housing 66 and are each reciprocable between respective upper and lower positions relative to housing 66. The upper moving mandrel portion 1 38 is attached to lower valve seat carrier 106 and may be said to be operably associated with lower valve seat carrier 106 so that upper and lower positions of the upper moving mandrel portion 1 28 correspond to upper and lower positions of the lower valve seat holder 106 relative to housing 66.

The lower position of lower valve seat holder 106 as illustrated in Fig. 2B corresponds to the closed position of spherical valve member 92 as illustrated. Upon upward movement of lower valve seat holder 106 relative to housing 66, the spherical valve member 92 is moved axially upward relative to housing 66 and is rotated to its open position as previously described by the engagement of eccentric hole 1 26 with eccentric lug 118.

The lower valve mandrel portion 140 includes a first uppermost section 142, a second section 144 connected to the lower end of first section 142, a third section 146 connected to the lower end of section section 144, and a lower adapter 148 connected to the lower end of third section 146. Lower adapter 148 includes an externally threaded lower end 1 50 for connection to those components of test string 34 located below drill pipe tester valve 62.

Extending radially outward from an outer surface of third section 146 of lower moving mandrel portion 140 of moving mandrel means 1 36 is a positioning lug 1 52.

Disposed within a radially inner surface of second valve casing portion 74 of housing 66 is a positioning slot means 1 54 in which positioning lug 1 52 is received. A laid-out view of positioning slot means 1 54 and positioning lug 1 52 is shown in Fig. 3 which is a view taken generally along line 3-3 of Figs.

2C and 2D. The positioning slot means 1 54 and positioning lug 1 52 are so arranged and constructed that when test string 34 is rotated clockwise and a weight of testing string 34 is set down upon housing 66, the lower moving mandrel portion 140 and with it the upper moving mandrel portion 1 38 are moved to their upper positions relative to housing 66 thereby opening spherical valve member 92.

The position of lug 1 52 relative to slot 1 54 as the test string 34 is lowered into the well is shown in solid lines in Fig. 3. The position after test string 34 is set down is shown in phantom lines.

It will be understood by those skilled in the art that when the weight of test string 34 is set down upon housing 66, the lower moving mandrel portion 1 40 will not move axially relative to casing 16 of the well (see Fig. 1), because of engagement of the packer means 46 (see Fig. 1) with the casing 16.

The packer means 46 is preferably a "Halliburton RTTS" retrievable packer such as is shown and described in Halliburton Services Sales and Service Catalog No. 40 at Page 3490. The design of such packers is well known to those skilled in the art and generally includes a drag block means for engaging the casing of the well so as to provide an initial friction between the packer and the well.

When the weight of the drill string is set down upon the packer means 46, the drag block means allows a set of slips to be set against the casing and then the same continu ous downward motion serves to compress and expand a packer element to seal the annulus 40 between the test string 34 and the well casing 1 6. The actuating components of the packer means 46 include a packer slot means (not shown) and a packer lug means (not shown) constructed similar to the lug means 1 1 ski2 and the slot means 1 54 shown in Fig. 3, i.e., the slot and lug means of the packer -46 are constructed the same as the slot and lug means of the drill pipe tester valve 62, so that the same setting down motion of the test string 34 which opens the spherical valve member 92 also sets the packer means 46.

When the well testing string 34 is picked up, the housing 66 is moved upward relative to the well casing 1 6 and accordingly the I moving mandrel means 1 36 is moved down ward relative to housing 66 to its said lower position thereby once again closing spherical valve member 92.

Lower moving mandrel portion 1 40 in cludes an upper end 1 56 adapted for engage ment with a lower end 1 58 of upper moving mandrel portion 1 38, so that when the weight of the test string 34 is set down upon housing 66, the lower moving mandrel portion 140 is moved moved upward relative to housing 66 and is engaged with upper moving mandrel portion 138 to move the upper moving mandrel por tion 1 38 upward relative to housing 66, thereby opening spherical valve member 92.

The moving mandrel means 1 36 includes latch means generally indicated by the nu meral 1 60 for latching spherical valve mem ber 92 in its said closed position as the test string 34 is lowered into the well.

Latch means 1 60 includes a plurality of resilient spring collet fingers such as fingers 162, 1 64 and 166, extending downward from upper moving mandrel portion 1 38.

Each of said spring collet fingers includes a head 1 68 at its lower end with radially inner and outer upward facing shoulders 1 70 and 172, respectively, defined upon the head 1 68. Shoulders 170 and 1 72 are tapered.

Latch means 1 60 further includes an annu lar radially inner recess means 1 74 in an inner surface of housing 66. An upper end of said recess means is defined by a downward facing annular shoulder 1 76 of housing 66.

Recess means 1 74 provides a means for receiving the radially outer upward facing shoulders 1 72 of the spring collet fingers when the spherical valve member 92 is in its said closed position. Latch means 1 60 further includes a radially outer cylindrical surface means 1 78 on first section 142 of lower moving mandrel portion 140 for engaging a radially inner surface 1 80 of the heads 1 68 of the spring collet fingers, and holding the heads 1 68 within the recess means 1 74 of housing 66 when the spherical valve member 92 is in its closed position.

Additionally, lower moving mandrel portion 140 includes a radially outer annular recess means 1 82 located below radially outer cylindrical surface 178, for receiving the radially inner upward facing shoulders 1 70 of heads 1 68 of the spring collet fingers, such as finger 166, when the upper end 1 56 of lower moving mandrel portion 1 40 is in engagement with lower end 1 58 of upper moving mandrel portion 1 38.

The purpose of latch means 1 60 is best understood by describing the functions it accomplishes in sequence as the well test string 34 is lowered into the well, then as the well test string 34 is set down upon the housing 66, and then as the well test string 34 is subsequently picked up.

When the well test string 34 is run into the well, the components of the drill pipe tester valve 62, and particularly the latch means 160, are in the relative positions illustrated in Figs. 2A-2E. As is seen in Fig. 2C, the latch means 1 60 at this point provides a means for releasably locking upper moving mandrel portion 1 38 relative to housing 66 in a position holding spherical valve member 92 in its said closed position as the well test string 1 34 is lowered into a well.This upper moving mandrel portion 1 38 is locked in the described position due to engagement of outer shoulder 1 78 of the heads 168 of the collet fingers with the recess 1 74 of the housing 66, and due to the presence of the radially outward surface 1 78 of lower moving mandrel portion 140 which holds the heads 1 68 in the described position.

When the well test string 34 is located in its desired final position within the well, the weight of the test string is set down upon the housing 66 as previously described. During that operation the latch means 1 60 provides a means for releasing upper moving mandrel portion 1 38 relative to housing 66.This releasing function is accomplished by upward movement of lower moving mandrel portion 140 relative to upper moving mandrel portion 1 38 prior to engagement of the upper end 1 56 of lower moving mandrel 140 with the lower end of upper moving mandrel portion 1 38. When the inner shoulders 1 70 of the heads 1 68 of the collet fingers become located opposite the radially outer recess 1 82 of lower moving mandrel portion 140, the heads 1 68 of the collet fingers are moved radially inward into the recess 1 82 thereby releasing upper moving mandrel portion 1 38 from its previously latched engagement with housing 66.

Additionally, as the weight of test string 34 continues to be set down upon housing 66, the latch means 1 60 provides a means for releasably locking lower moving mandrel portion 1 40 to upper moving mandrel portion 1 38. This is accomplished bywthe receiving of the inner shoulder 1 70 of heads 1 68 within recess 1 82 of lower moving mandrel portion 1 40 and the subsequent upward movement of both upper and lower moving mandrel portions 1 38 and 140 relative to housing 66 after the upper end 1 56 of lower moving mandrel portion 140 engages the lower end 1 58 of upper moving mandrel portion 1 38.

Additional upward movement of the upper and lower moving mandrel portions relative to housing 66 provides the axial upward movement of valve member 92 necessary to move the same to its open position as previously described.

When the well testing procedures are completed or whenever for some reason the test string 34 is picked up from the well, the latch means 160, due to the fact that it has latched the upper and lower moving mandrel portions 1 38 and 140 together, provides a means for moving the upper moving mandrel portion 1 38 downward relative to housing 66 when the well test string is picked up. This is because the lower moving mandrel portion 140 is fixed relative to the casing 1 6 of the well because of engagement of the packer means 46 with the casing 16.Therefore, since the upper and lower moving mandrel portions are for a time latched together by latch means 160, this causes the upper moving mandrel portion 1 38 to also be held in position relative to well casing 1 6 when the well test string 34 is initially picked up.

Subsequently, during the pick up operation, after the upper moving mandrel portion 1 38 has moved downward relative to housing 66 sufficiently so that lower annular surface 1 32 of lower valve seat carrier 106 engages upper surface 1 34 of housing 66, and radially outer shoulder 172 of heads 1 68 of the collet spring fingers are once again received in the inner recess 1 74 of housing 66, the lower moving mandrel portion 140 is released from its latched attachment to the upper moving mandrel portion 138 and the components of the drill pipe tester valve 62 are once again in the relative positions illustrated in Figs.

2A-2E.

The third section 1 46 of lower moving mandrel portion 1 40 includes an equalization portion means 1 84 disposed through a wall thereof for communicating the flow passage 90 of housing 66 below spherical valve member 92 with the annulus 40 between the test string 34 and the well casing 6 when spherical valve member 92 is in its closed position.

The annulus 40 may be generally described as a zone outside of housing 66.

Third section 146 of lower moving mandrel portion 140 further includes an outer cylindri cal' surface 1 86 closely received within an inner cylindrical surface 1 88 of a lower end of second valvesasing portion 74 of housing 66.

An annulus sealing means 190 is disposed between outer cylindrical surface 1 86 and inner cylindrical surface 188. Non-metallic backup rings 1 92 are provided on either side of the annular seals 1 90. The housing 66, lower moving mandrel portion 140, and an ndlar seal means 1 90 are so arranged and constructed that when the weight of the test string 34 is set down upon housing 66, and the lower moving mandrel portion 1 40 is moved upward relative to housing 66, the equalization portion 1 84 is closed before the spherical valve member 92 is open.

-Equalization port 1 84 also equalizes the pressure across the walls of moving- mandrel 1 36 to prevent inward collapse thereof due to the hydrostatic head in annulus 40. It also prevents a hydraulic pressure lock from occurring between spherical valve member 92 and the formation tester valve 60 when the moving mandrel means 1 36 is telescoped into housing 66.

Upward movement of lower moving mandrel portion 140 relative to housing 66 is limited by engagement of an upward facing shoulder 1 94 of lower moving mandrel portion 1 40 with a downward facing shoulder 1 96 of housing 66, which combination of shoulders 1 94 and 1 96 may generally be described as a stop means for limiting upward movement of lower moving mandrel portion 140 relative to housing 66.

Referring now to Figs. 4A-4E, an alternative embodiment of the present invention is shown and generally designated by the numeral 62A. In the alternative embodiment 62A of Figs. 4A-4E, elements of that drill pipe tester valve which are identical to the embodiment shown in Figs. 2A-2E are identified by the same numerals as used in Figs.

2A-2E, and corresponding elements which have been modified to some extent are designated by the same numeral with a suffix "A" added thereto.

The primary difference between the drill pipe tester valve 62A of Figs. 4A-4E and the previously described drill pipe tester valve 62 of Figs. 2A-2E is that in the embodiment of Figs. 4A-4E the latch means 1 60 has been completely deleted, and a resilient coil compression spring 1 98 has been disposed aboutpositioning mandrel 1 09A between a downward facing shoulder 200 of housing 66A and an upward facing shoulder 202 of upper valve seat holder 104.

The spring 1 98 provides an automatic fillup feature for the drill pipe tester valve 62A so that-as the well test string 34 is lowered into the well, well fluid from the well annulus 40 is allowed to flow upward through spherical valve member 92 when the pressure of the well fluid below spherical valve member 92 is sufficient to overcome the pressure of fluid above spherical valve member 92 plus the downward force exerted by spring 198.

This feature is more fully described below.

Upon initially starting to lower the well test string 34 into the well, the spherical valve member is held downward in its closed position with lower surface 1 32 of lower valve seat holder 106 in engagement with upper surface 1 34 of housing 66A.

As the test string 34 is lowered lower into the well, the hydrostatic pressure of the well fluid in the well annulus 40 steadily increases until the force exerted upon the lower surface of valve member 92 by the pressure of the well fluid in the well annulus, which is communicated with the lower surface 100 through equalization port 184A, becomes equal to the force exerted downward upon the upper surface 196 of valve member 92 by fluid in the flow passage 90 above valve member 92 plus the downward force exerted by spring 1 98. At that point, any further increase of the pressure of the well fluid in the annulus 40 as the test string 34 is further lowered causes the spherical valve member 92 to be moved axially upward relative to housing 66A thereby compressing spring 198.

This upward movement of spherical valve member 92 causes it to be rotated partially toward its fully open position, thereby cracking the valve open so that some of the well fluid from the annulus 40 is allowed to flow upward through the bore 94 of spherical valve member 92 into the flow passage 90 located above spherical valve member 92.

Once the force being exerted on spherical valve member 92 from below become less than the forces exerted on spherical valve member 92 from above, the compression spring 1 98 once again pushes spherical valve member 92 downward relative to casing 66A to its closed position as shown in Fig. 4B.

Thus, as the well string 34 is lowered into the well, periodically the pressure of the well fluid in the annulus 40 overcomes the pressure of the fluid above spherical valve member 92 in the flow passage 90 and overcomes the spring 1 98 and thereby "burps" the valve allowing a portion of well fluid to flow upward through the valve 92 thereby filling the string of pipe located above valve member 92 with well fluid.

Whenever it is desired to pressure test a string of pipe located above spherical valve member 92, the lowering of the string of pipe is stopped and the spherical valve member 92 is soon moved downward to its closed position by the compression spring 198, if it indeed is not already in its downward closed position when the lowering is first stopped.

Thus, the spring 1 98 may be said to be a means for automatically closing the spherical valve member 92 when the string of pipe is statically positioned within the well. This permits the string of pipe located above spherical valve member 92 to be pressure tested.

Additionally, the spring 1 98 may be said to be a means for automatically opening the spherical valve member 1 92 and allowing well fluid within the well to fill the string of pipe above spherical valve member 92 as the string of pipe is lowered into the well as previously described with regard to the "burping" feature.

The methods of utilizing the drill pipe tester valves of the present invention are generally as follows.

The- purpose of the drill pipe tester valve is to allow the drill pipe to be pressure tested periodically as it is lowered into the well to determine whether there are any leaks between successive joints of drill pipe.

The drill pipe tester valve of the present invention is generally run directly above a formation tester valve 60 such as the formation tester of Holden, et al, disclosed in U.S.

Patent No. 3,856,085. The use of the drill pipe tester valve of the present invention provides a method for testing the drill pipe without exerting the test pressures upon the spherical valve member of the formation tester valve 60 (see Fig. 1) with the problems accompanied therewith as previously described.

The drill pipe tester valve 62 or 62A is attached to a lower end of a string of pipe, and below the drill pipe tester valve 62 is connected the formation tester valve 60 and a packer means 46 generally as shown in Fig.

1.

The string of pipe or the well test string 34 is then lowered into the well. The string of pipe above the spherical valve member 92 is filled with fluid either by filling from the work deck 26 if the drill pipe tester valve 62 is utilized, or by automatic filling if the drill pipe tester valve 62A is utilized.

Periodically, during the lowering operation, the lowering is stopped and the string of pipe is located statically within the well. Then the string of pipe is pressure tested while the string of pipe is stopped and while the spherical valve member is in its closed position. This stopping is done periodically so that successive portions of the string of pipe are pressure tested periodically as the string of pipe is lowered into the well.

During the pressure testing operation, the lower valve seat holder 106 is supported against the downward force exerted upon spherical valve member 92 by pressure testing of the pipe, from the housing 66 by engagement of the downward facing surface 1 32 of lower valve seat holder 106 with the upward facing annular surface 1 34 of housing 66.

If the drill pipe tester valve 62 of Figs.

2A-2E is utilized, having the latch means 160, then the upper moving mandrel portion 1 60 is locked relative to the housing 66 thereby holding the spherical valve member 92 in the closed position while the string of pipe is being lowered into the well. When the string of pipe is finally positioned within the well and the weight of the string of pipe is set down upon the housing 66, the upper moving mandrel portion of the drill pipe tester valve 62 is released relative to the housing 66 and the lower moving mandrel portion is locked to the upper moving mandrel portion.Then upon picking up the string of pipe after the testing procedure is completed, or whenever it is necessry to pick up the string of pipe for some other reason, the upper moving mandrel portion is moved downward relative to the housing 66, thereby closing the spherical valve member 92, and the upper moving mandrel portion is released from its latched attachment to the lower moving mandrel portion 1 40.

If the drill pipe tester valve 62A of Fig. 4E is utilized, having the automatic fill-up feature due to the presence of the coil spring 198, the spherical valve member 92 is urged resiliently downward relative to housing 66A towards the closed position of the spherical valve member 92 by the resilient spring 1 98.

As the test string 1 34 is lowered into the well, well fluid from the annulus 40 is communicated to the lower surface of the spherical valve member 92 and exerts periodically a sufficient well fluid pressure against said lower surface 100 of the spherical valve member 92 to overcome a downward force of any fluid which may be present above spherical valve member 92 and a downward force of resilient spring 198, and thereby moves the spherical valve member 1 92 upward relative to the housing 66A. This rotates the spherical valve member to a partially open position thereby allowing well fluid from the annulus 40 to flow upward through spherical valve member 92 to fill the string of pipe as the string of pipe is lowered into the well.

Utilizing the drill pipe tester valve of either Figs. 2A-2E or Figs. 4A-4E, once the test string 34 is lowered into its final position within the well, the weight of the string of pipe is set down upon the housing 66 thereby moving the spherical valve member 92 upward relative to the housing 66 and rotating the spherical valve member 92 to an open position so that it does not interfere with the formation testing operation or with the lowering of wire line tools through the test string.

Also, with either the embodiment of Figs.

2A-2E or that of Figs. 4A-4E, the packer means 46 is provided below the drill pipe tester valve for sealing the annulus 40 between the test string 34 and the well casing 16, and the packer means 46 utilizes a J-slot and lug similar to that of the drill pipe tester valve as shown in Fig. 3, so that when the weight of the test string 34 is set down upon the housing 66 to open the valve member 92, that same setting down motion also sets the packer means against the well casing.

Thus, it is seen that the drill pipe tester valve of the present invention readily achieves the ends and advantages mentioned as well as those inherent therein. While presently preferred embodiments of the invention have been illustrated for the purpose of this disclosure, numerous changes in the arrangement and construction of parts may be made by those skilled in the art.

Claims (45)

1. A pipe tester valve for installation in a pipe string, comprising: a housing having a first end adapted to be connected to a string of pipe, and having a flow passage therethrough; a spherical valve member disposed in said flow passage of said housing; lug means for engaging said spherical valve member and rotating said spherical valve member between open and closed positions wherein said flow passage is open and closed, respectively; and lower valve seat means for sealingly engaging a lower surface of said spherical valve member, said lower valve seat means having a downward facing surface supportably engaged by an upward facing surface of said housing when said spherical valve member is in its said closed position, so that downward forces exerted (in use) upon said spherical valve member in its said closed position due to fluid pressure in said string of pipe above said spherical valve member are transmitted substantially entirely to said housing through said engagement of said downward facing surface and said upward facing surface.

2. A pipe tester valve for installation in a pipe string, comprising: a housing having a first end adapted to be connected to a string of pipe, and having a flow passage therethrough; a spherical valve member disposed in said flow passage of said housing; lug means, attached to said housing, for engaging said spherical valve member and rotating said spherical valve member between open and closed positions wherein said flow passage is open and closed, respectively, as said spherical valve member is moved axially relative to said housing and said lug means; and moving means for moving said spherical valve member axially relative to said housing between its said open and closed positions, said moving means including lower valve member seat means having a downward facing surface supportably engaged by an upward facing surface of said housing when said spherical valve member is in its said closed position, so that downward forces exerted on said spherical valve member in its said closed position (in use) due to fluid pressure in said string of pipe above said spherical valve member are transmitted substantially entirely to said housing through said engagement of said downward facing surface and said upward facing surface.

3. A valve according to claim 2, wherein: said lower valve member seat means of said moving means is movable between an upper and a lower position, relative to said housing, said upper and lower positions of said lower valve member seat means corresponding to said open and closed positions of said spherical valve member, respectively.

4. A valve according to claim 3, wherein: said moving means includes a moving mandrel means having an upper end reciprocably received within a lower end of said housing and reciprocable between an upper and a lower position relative thereto, said moving mandrel means being operably associated with said lower valve member seat means so that said upper and lower positions of said moving mandrel means correspond to said upper and lower positions of said lower valve member seat means.

5. A valve according to claim 4, wherein: one of said moving mandrel means and said housing includes a positioning lug; and the other of said moving mandrel means and said housing includes a positioning slot means in which said positioning lug is received, said positioning slot means and positioning lug being so arranged and constructed that when a weight of said string of pipe is set down on said housing said moving mandrel means is moved moved to its upper position relative to said housing thereby opening said spherical valve member, and when said string of pipe is picked up said moving mandrel means is moved to its lower position relative to said housing.

6. A valve according to claim 4 or 5, wherein: said moving mandel means includes an upper moving mandrel portion attached to said lower valve member seat means and a lower moving mandrel portion having an upper end adapted for engagement with a lower end of said upper moving mandrel portion, so that when said weight of said string of pipe is set down on said housing said lower moving mandrel portion is moved upward relative to said housing and is engaged with said upper moving mandrel portion to move said upper moving mandrel portion upward relative to said housing thereby opening said spherical valve member.

7. A valve according to claim 6, wherein: said lower moving mandrel portion includes an equalization port means, disposed through a wall thereof, for communicating said flow passage of said housing below said spherical valve member with a zone outside of said housing when said spherical valve member is in its closed position.

8. A valve according to claim 7, wherein: said lower moving mandrel portion includes an outer cylinderal surface closely received within an inner cylindrical surface of said lower end of said housing; and wherein an annular sealing means is provided disposed between said outer cylindrical surface of said lower moving mandrel portion and said inner cylindrical surface of said lower end of said housing, said housing, moving mandrel means and annular sealing means being so arranged and constructed that when said weight of said string of pipe is set down on said housing said equalization port means is closed before said spherical valve member is opened.

9. A valve of claim 6,7 or 8, further comprising: stop means for limiting upward movement of said lower moving mandrel portion relative to said housing.

10. A valve according to any of claims 1 to 9, wherein: said housing includes an upper housing portion, and a lower housing portion, an upper end of said lower housing portion being received within and attached to a lower end of said upper housing portion.

11. A valve according to any of claims 1 to 10, wherein: said lug means includes a lug-carrying mandrel received within said upper housing portion and retained in place therein by engagement with said upper end of said lower housing portion.

1 2. A valve according to any of claims 1 to 11, wherein: said upward facing surface of said housing is defined on said upper end of said lower housing portion.

1 3. A valve according to any of claims 1 to 12, further comprising: automatic means for automatically closing said spherical valve member when said string of pipe is statically positioned within a well so that said string of pipe may be pressure tested, and for automatically opening said spherical valve member and allowing well fluid within said well to fill said string of pipe above said spherical valve member as said string of pipe and spherical valve member are lowered into said well.

14. A valve according to claim 13, wherein: said automatic means includes spring means for resiliently urging said spherical valve member downward relative to said housing toward its said closed position.

1 5. A valve according to claim 14, wherein: said spring means includes a coil compression spring located above said spherical valve member.

1 6. A valve according to claim 15, wherein: said coil compression spring is connected between said housing and an upper valve seat means for sealing against an upper surface of said spherical valve member.

1 7. A valve according to any of claims 1 to 12, further comprising: spring means for resiliently urging said spherical valve member downward toward its said closed position, and for allowing said spherical valve member to be moved upward by fluid pressure exerted on a lower surface of said spherical valve member as said string of pipe and tester valve are lowered into a well, so that said string of pipe above said tester valve is automatically filled with said well fluid as said string of pipe is lowered into said well.

18. A valve according to claim 17, wherein: said spring means includes a coil compression spring connected between said housing and an upper valve seat means against which an upper surface of said spherical valve member is sealingly engaged.

1 9. A well test string including a pipe tester valve as claimed in any preceding claim, and further comprising: a formation tester valve connected to a lower end of said pipe tester valve so that said string of pipe above said pipe tester valve may have said fluid pressure exerted thereupon to test said string of pipe without said fluid pressure being exerted upon said formation tester valve.

20. A test string according to claim 19, wherein: said moving means of said pipe tester valve includes an equalization port means, disposed through a wall thereof, for communicating said flow passage of said housing below said spherical valve member with an annulus between said test string and a well casing when said spherical valve member is in its said closed position.

21. A test string according to claim 1 9 or 20, further comprising: packer means, connected to said formation tester valve for sealing an annulus between said well test string and a well casing above a formation of said well which is to be tested, said packer means including a packer slot means and a packer lug means cooperating with said packer slot means, said packer slot and lug means being arranged and constructed similar to said positioning slot means and positioning lug means of said pipe tester valve, so that the same setting down motion of said well test string which opens said spherical valve member of said pipe tester valve also sets said packer means.

22. A valve according to any preceding claim, which also includes latch means whereby said spherical valve member may be latched in its said closed position as said string of pipe and pipe tester valve are lowered into a well.

23. A valve according to any of claims 4 to 9, which also includes latch means comprising first locking means for releasably locking said upper moving mandrel portion relative to said housing in a position holding said spherical valve member in its said closed position as said string of pipe and pipe tester valve are lowered into a well prior to setting down of the weight of said string of pipe on said housing.

24. A valve according to claim 23, wherein: said latch means further includes first releasing means for releasing said upper mandrel portion relative to said housing when said weight of said string of pipe is set down on said housing.

25. A valve of claim 2 or 3, wherein: said latch means further includes a second locking means for releasably locking said lower moving mandrel portion to said upper moving mandrel portion when said weight of said string of pipe is set down on said housing, and for moving said upper moving mandrel portion downward relative to said housing when said string of pipe is picked up after being set down, so that said spherical valve member is closed when said string of pipe is picked up.

26. A valve according to claim 25, wherein: said latch means further includes a second releasing means for releasing said upper moving mandrel portion from said lower moving mandrel portion after said spherical valve member is closed when said string of pipe is picked up.

27. A valve according to claims 24 to 26, wherein said first and second locking means and said first and second releasing means of said latch means are all comprised of: a plurality of resilient spring collet fingers extending downward from said upper moving mandrel portion, each of said spring collet fingers including a head on a lower end thereof with radially inner and outer upward facing shoulders defined upon said head; an annular radially inner recess means in said housing, an upper end of which recess means is defined by a downward facing annular shoulder, for receiving said radially outer upward facing shoulders of said spring collet fingers when said spherical valve member is in its said closed position; a radially outer cylindrical surface means, on said lower moving mandrel portion, for engaging a radially inner surface of said heads of said spring collet fingers and holding said heads within said recess means of said housing when said spherical valve member is in its lid closed position; and a radially outer annular recess means, disposed in said lower moving mandrel portion below said radially outer cylindrical surface means of said lower moving mandrel portion, for receiving said radially inner upward facing shoulders of said heads of said spring collet fingers when said upper end of said lower moving mandrel portion is in engagement with said lower end of said upper moving mandrel portion.

28. A valve according to any of claims 22 to 27, wherein: said housing includes an upper housing portion and a lower housing portion, an upper end of said lower housing portion being received within and attached to a lower end of said upper housing portion.

29. A valve according to claim 28, wherein: said lug means includes a lug carrying mandrel received within said upper housing portion and retained in place therein by engagement with said upper end of said lower housing portion.

30. A valve according to claim 28 or 29, wherein: said upward facing surface of said housing is defined upon said upper end of said lower housing portion.

31. A well test string including a pipe tester valve as claimed in any of claims 22 to 30 and further comprising: a formation tester valve connected to a lower end of said pipe tester valve so that said string of pipe above said pipe tester valve may have said fluid pressure exerted thereupon to pressure test said string of pipe without said fluid pressure being exerted upon said formation tester valve.

32. A well test string including a pipe tester valve as claimed in any of claims 23 to 27 wherein: said lower moving mandrel portion of said pipe tester valve includes an equalization port means, disposed through a wall thereof, for communicating said flow passage of said housing below said spherical valve member with an annulus between said test string and a well casing when said spherical valve member is in its said closed position.

33. A string according to claim 31 or 32, further comprising: packer means, connected to said formation test valve, for sealing said annulus between said well test string and said well casing above a formation of said well which is to be tested, said packer means including a packer slot means and a packer lug means cooperating with said packer slot means, said packer slot and lug means being arranged and constructed similar to said positioning slot means and positioning lug means of said pipe tester valve so that the same setting down motion of said well test string which opens said spherical valve member of said pipe tester valve also sets said packer means.

34. A method of pressure testing a string of pipe as said string of pipe is lowered into a well, said method comprising the steps of: providing on a lower end of said string of pipe a pipe tester valve including a housing having a flow passage therethrough, a spherical valve member disposed in said flow passage of said housing, and lower valve seat means sealingly engaging a lower surface of said spherical valve member, said lower valve seat means having a downward facing surface supportably engaged by an upward facing surface of said housing when said spherical valve member is in a closed position; lowering said string of pipe into said well; filling said string of pipe above said spherical valve member with a fluid; stopping said lowering of said string of pipe periodically; pressure testing said string of pipe while said lowering of said string of pipe is stopped and said spherical valve member is in its said closed position, so that successive portions of said string of pipe are pressure tested periodically as said string of pipe is lowered into said well; and supporting said lower valve seat means, against a downward force exerted on said spherical valve member by said pressure testing of said string of pipe, from said housing by said engagement of said downward facing surface of said lower valve seat means and said upward facing surface of said housing.

35. A method according to claim 34, wherein said step of filling said string of pipe with fluid further comprises the steps of: urging said spherical valve member resiliently downward relative to said housing toward its said closed position by means of a resilient spring; communicating a well fluid from outside said housing with a lower surface of said spherical valve member as said string of pipe is lowered into said well; exerting sufficient well fluid pressure against said lower surface of said spherical valve member to overcome a downward force of said resilient spring and to move said spherical valve member upward relative to said housing; and rotating said spherical valve member to an open position as said spherical valve member is moved upward relative to said housing, thereby allowing said well I fluid to fill said string of pipe as said string of pipe is lowered into said well.

36. A method according to claim 34, further comprising the step of: setting down a weight of said string of pipe on said housing when said string of pipe is finally positioned within said well and thereby moving said spherical valve member upward relative to said housing and rotating said spherical valve member to an open position.

37. A method of testing a formation of a well, said formation testing method including the pressure testing method as claimed in claim 34, 35 or 36, and further comprising the steps of: providing a packer means, connected to said pipe tester valve, for sealing an annulus between said string of pipe and a well casing; and setting said packer means against said well casing by said setting down of said weight of said string of pipe on said housing.

38. A method according to claim 34, wherein the pipe tester valve also includes an upper moving mandrel portion attached to said lower valve seat means, and a lower moving mandrel portion having an upper end adapted for engagement with a lower end of said upper moving mandrel portion; and wherein, after lowering said string of pipe into said well, said upper moving mandrel portion is locked relative to said housing and said spherical valve member is held in a closed position while said string of pipe is being lowered into said well.

39. A method according to claim 38, further comprising the step of: setting down a weight of said string of pipe on said housing when said string of pipe is finally positioned within said well and thereby moving said spherical valve member upward relative to said housing and rotating said spherical valve member to an open position.

40. A method according to claim 38 or 39, further comprising the step of: releasing said upper moving mandrel portion relative to said housing when said weight of said string of pipe is set down on said housing.

41. A method according to claim 40, further comprising the step of: locking said lower moving mandrel portion to said upper moving mandrel portion when said weight of said string of pipe is set down on said housing.

42. A method according to claim 41, further comprising the steps of: picking up said string of pipe; moving said upper moving mandrel portion downward relative to said housing when said string of pipe is picked up; and thereby closing said spherical valve member when said string of pipe is picked up.

43. A method according to claim 42, further comprising the step of: releasing said upper moving mandrel portion from said lower moving mandrel portion after said spherical valve member is closed when said string of pipe is picked up.

44. A pipe tester valve substantially as herein described with reference to Figs. 2A to 2E and 3, or Figs. 2A to 2E and 3 as modified by Figs. 4A to 4E of the accompanying drawings.

45. A string of pipe having installed therein a pipe tester valve as claimed in any of claims 1 to 33 or 44.

46; A method of pressure testing a string of pipe as claimed in claim 45, substantially as herein described with reference to the accompanying drawings.