US3494417A - Well tools - Google Patents

Description

Feb. 10, 1970 J. v. FREDD WELL TOOLS Original Filed June 10, 1965 Il .Sx

11 Sheets-Sheet 2 ses INVENT OR JOHN V. FREUD Wwf/m J. V. FREDD Feb. 10, 1970 WELL TOOLS ll Sheets-Sheet 5 Original Filed June 10, 1965 FIG-7 FIG I4 INVENTOR JOHN V. FREDD Feb. 10, 1970 J. v. FREDD 3,494,417

WELL TooLs Original Filed June 10, 1965 l1 Sheets-Sheet 4 564 47a .rss 555 563 55s 5de 55a 55o John V Fredd ATTORNEYS Feb. l0, 1970 J. V. FREDD WELL TOOLS Original Filed June 10, 1965 Fig2-B 11 Sheets-Sheet 5 Figa-C mvENToR John V. Fred d ATTORNEYS Feb. l0, 1970 J, Vl FREDD 3,494,417 l Original Filed June 10, 1965 1l Sheets-Sheet '7 mvENr'oR John V. Fredd ATTORNEYS Feb. 10, 1970 J. v. FREDD 3,494,417

WELL TOOLS Original Filed June l0, 1965 11 Sheets-Sheet 8 .i J HN V. FR F|G G o EDO WX ATTORNEY gua-l5@ BY Feb. 10, 1970 J. v. FREDD WELL TOOLS ll Sheets-Sheet 9 Original Filed June 10, 1965 INVENTOR JOHN V. FREDD fd ATTORNEY Feb. 10, 1970 J. v. FREDD WELL TOOLS original Fued .June 1o, 1965 1l Sheets-Sheet l0 JOHN V. FREDD BY ff/@ mh J. V. FREDD WELL TOOLS Feb. 1o, 1970 -aolc FIG .-25

11 Sheets-Sheet 11 INVENTOR JOHN V. FREDD FIG.2|

4 M W j ATTORNEY Original Filed June 10, 1965 United States Patent 3,494,417 WELL TOOLS John V. Fredd, Dallas, Tex., assignor to Otis Engineering Corporation, Dallas, Tex., a corporation of Delaware Continuation of application Ser. No. 462,800, June 10, 1965. This application Jan. 29, 1968, Ser. No. 703,519

Int. Cl. E21b 43/00 U.S. Cl. 166-73 15 Claims ABSTRACT 0F THE DISCLOSURE A well fluid flow control system having a subsurface safety valve actuated to a closed position by a columnar weight forming a part of the ow conductor and having pressure responsive means for maintaining said columnar weight in a position holding the valve open under predetermined conditions, said pressure responsive means being responsive to predetermined flow conditions to release the columnar weight to close the valve, whereby the valve is adapted for use at great depths in the well flow conductor. A hanger system for the subsurface valve for supporting the tubing string of the flow conductor in the Well bore in a manner permitting fluid pressure to be applied from the surface into the annular space Within the Well bore exteriorly of the flow conductor through the hanger assembly.

This invention relates to well tools and more particularly relates to well flow control systems.

This application is a continuation of my co-pending application Ser. No. 462,800, filed June 10, 1965, now abandoned.

One object of this invention is to provide a new and improved flow control system for controlling fluid ow through a flow conductor responsive to a predetermined change in one or more variables which may be related to or independent of the conditions within the conductor.

It is another object of the invention to provide a new and improved safety valve system for use in a flow conductor of a well. A

It is a further object of the invention to provide a flow control system including a subsurface valve which may be used in a well conductor at any desired depth.

It is a still further object of the invention to provide a uid iloW control system including a subsurface valve which is not limited in use to a particular depth and thus may be installed in a flow conductor below the depth at which paraffin normally forms in the conductor.

It is another object of the invention to provide a fluid' ow control system for controlling fluid iiow through a well conductor which does not include a small hydraulic line between the surface control elements of the system and the subsurface valve operable in response to such control elements.

It is' a further object of the invention to provide a -uid flow control system including a subsurface valve biased toward a closed position by a weight column which is counterbalanced to hold the valve in open position by surface controlled iiuid pressure in an annular flow passage around and separate from the flow passage in which the valve is dispensed and through which the iiuid controlled by the device flows.

It is an additional object of the invention to provide a fluid flow control system including a subsurface valve which is weight biased toward a closed position and held in an open position by a pressure medium controllable in response to variations in one or more conditions which are independent of the controlled uid flow through the device.

ice

It is a still further object of the invention to provide a uid flow control system including a surface controlled subsurface valve which may be landed in a nipple of a well conductor without removing the conductor from the well.

It is another object of the invention to provide a fluid flow control system including a subsurface valve having a full bore passageway extending therethrough whereby various well tools may be passed through the section of the flow conductor containing the subsurface valve.

It is an additional object of the invention to provide a fluid flow control system including a subsurface valve which may be installed in a flow conductor utilizing a minimum of surface equipment.

It is a further object of the invention to provide a fluid iiow control system including a tool for running in and positioning the subsurface valve included in the system. i

It is an additional object of the invention to provide a fluid ow control system which includes a tool for removing the subsurface valve which forms a principal component of the system.

It is another object of the invention to provide a fluid flow control system including a polished joint for positioning a subsurface valve and connecting an inner tubing string within a well bore while holding uid pressure within the tubing string.

It is a further object of the invention to provide a Afduid flow control system including a tubing hanger assembly for supporting a string of inner tubing within a well bore while permitting fluid pressure to be applied from the surface into an annular space within the well bore around the tubing string.

It is an additional object of the invention to provide a surface positioned tubing string hanger assembly having radially movable clamp rams and a radially movable lug ram through which fluid pressure is applied to an annular space within the well bore around the inner tubing string supported by the hanger.

The invention is therefore directed to a well uid flow control system having a tubular weight member forming a part of the ow conductor and movable longitudinally relative to the iiow conductor thereabove for actuating a valve between open and closed positions, saidl weight member being moved to a position holding the valve open by pressure responsive means exposed to fluid pressure in the well bore exteriorly of the flow conductor and the valve; and a hanger system for supporting the tubing string or ow conductor in the well in a manner permitting fluid pressure to be applied from the surface to the pressure responsive means.

Additional objects and advantages of the invention will be readily apparent from the reading of the following description of a device constructed in accordance with the invention, and reference to the accompanying draw- 'ings thereof, wherein:

FIGURES 1-A through l-F together constitute a longitudinal View partially in section and partially in elevation of the surface ow control valve employed in the system of the invention;

FIGURE 2 is a diagrammatic representation partially in section and partially in elevation of the flow control system with the subsurface valve installed in operational position and connected to a surface control unit included `in the system;

FIGURE 2-A is a diagrammatic representation partially in elevation and partially in section illustrating the well head portion of the system shown in FIGURE 2 at an intermediate stage in the process of landing and securing the subsurface valve and inner tubing string;

FIGURES 2-B and 2-C taken together constitute a longitudinal view partially in section and partially in elevation of the polished point assembly utilized in the proccdure of landing and securing of the inner tubing string in the well bore;

FIGURE 2-D is a longitudinal view partially in section and partially in elevation illustrating the hanger sub used in supporting the inner tubing string from the hanger assembly and including a back pressure valve assembly together with its running tool;

FIGURE 2-F is a top view partially in section and partially in elevation of the tubing string hanger assembly showing the hanger sub in section locked within the assembly;

FIGURE 2-F is a side view partially in section and partially in elevation of the hanger assembly of FIGURE 2-E with that portion in section being viewed along the line 2Fv-2F of FIGURE 2-E;

FIGURE 2-G is an enlarged top view partially in elevation and partially in section of the lug ram used in the hanger assembly of FIGURE 2-E;

FIGURE 2-H is a side view in elevation of the lug ram of FIGURE 2-Gg and,

FIGURE 2-I is a right end view in elevation of the lug ram of FIGURE 2-H;

FIGURE 3 is a sectional view taken along the line 3-3 of FIGURE l-B;

FIGURE 4 is a sectional view taken along the line 4-4 of FIGURE l-B;

FIGURE 5 is an exploded perspective View of the retainer assembly used in the telescoping joint to hold the upper end of the weight section within the lower end of the inner tubing string;

FIGURE 6 is a sectional View taken along the line 6 6 of FIGURE l-C;

FIGURE 7 is a perspective view of the detent collent used in the connection to the upper end of the subsurface valve;

FIGURE 8 is an enlarged fragmentary longitudinal view partially in section and partially in elevation of the flapper valve at hte lower end of the coupling between the weight section and the upper end of the subsurface valve, showing the apper valve latched in the open position as when running the weight section and tubing string into the well;

FIGURE 9 is a view similar to FIGURE 8, showing the flapper valve in closed position as when withdrawing the weight section and tubing string from the well;

FIGURE l() is a fragmentary view in elevation of the lower end of the weight section showing the back side of the flapper valve when the valve is in the open position and the weight section is engaged over the upper end of the subsurface valve unit illustrated in FIGURE l-C;

FIGURE 1l is an enlarged sectional view taken along the line 11-11 of FIGURES 1 and l-C;

FIGURE 12 is a sectional view along the line 12-12 of FIGURE 1-C;

FIGURE 13 is a sectional view along the line 13--13 of FIGURE l-D;

FIGURE 14 is a view in perspective of the sleeve which encases the ball valve;

FIGURE 15 is a view in perspective of the ball valve, its operator member, and the operator tube, showing the valve in open position;

FIGURE 15-A is a view in perspective illustrating the ball valve, its operator members, and the operator tube with the ball valve in closed position;

FIGURE 15-B is an enlarged, fragmentary, diagrammatic view of the valve sleeve of FIGURE 14 with the ball valve in position within the sleeve and the operator members removed showing one of the windows in the sleeve and illustrating the arcuate path followed by one of the operator holes of the ball valve as the ball valve moves between the open and closed positions;

FIGURE 16 is a sectional view along the line 16-16 of FIGURE l-D;

FIGURE 17 is a sectional view along the line 17-17 of FIGURE l-D;

FIGURE 18 is a sectional view taken along the line 18-18 of FIGURE l-E;

FIGURE 19 is a sectional view along the line 19-19 of FIGURE l-E;

FIGURE 20 is an exploded View in perspective illustrating the lower end of the lock sleeve and the primary collect lock of the lock mandrel assembly used in securing the subsurface valve in a nipple in the tubing of a well;

FIGURES 21 and 21-A taken together constitute a longitudinal view partially in section and partially in elevation of the running tool used to position the subsurface valve within a well bore, showing the tool engaged over the upper end of the operator tube of the Valve unit;

FIGURE 22 is a sectional View along the line 22-22 of FIGURE 2l;

FIGURE 23 is a sectional view along the line 23-23 of FIGURE 21;

FIGURE 24 is a fragmentary view partially in section and partially in elevation of the running tool showing the position of the collect of the tool as the tool is being latched over the upper end of the operator tube of the subsurface Valve unit;

FIGURE 25 is a longitudinal, fragmentary view, in section and elevation showing the running ltool collect position and shear pins severed as the tool is lifted from the operator tube of the subsurface valve unit after setting the unit in a well bore; and, y

FIGURE 26 is a longitudinal view partially in section and partially in elevation of the pulling tool for removing the subsurface valve from a well bore, showing the tool installed over the upper end of the operator tube of the subsurface valve.

A fluid ow control system is accordance with the invention is illustrated in FIGURE 2. The well is equipped, either initially or when installing the system, with a tubing String, such as the outer tubing string 42, provided with a landing nipple 41 in which the subsurface valve assembly 30 is landed and removably secured. The outer tubing string extension 42a extends downwardly through a well packer 420 which is any suitable form of packer which will seal the annular space between the outer tubing string and the casing 421 of the well. Also, the tubular extension 43a on the lower end of the subsurface valve may extend downwardly to any desired depth withor below the tubing extension 42a. The well bore may be plugged back by cement or other suitable material at 422 while the casing is perforated as at 421a above the cement plug to permit formation fluids to flow into the well ibore below the packer 420. The outer tubing string 42 and the inner tubing string 43 are supported at the surface from the well head assembly 423 which may include a rst master valve 424, a second master valve 425, and a swab valve 430. Between the second master valve and the swab valve a T or cross-connection 431 is connected to permit the securing of a flow line 432 leading to conventional surface equipment such as a separator and a tank battery, not shown, for handling the fluids produced from the well. The upper end of the swab valve is closed by a flange 433 through which a conventional needle valve 434 and a pressure gauge 435 are secured to permit a determination of the pressure within the well head assembly. The inner tubing string 43 extending to the subsurface valve is supported from the hanger assembly 440 positioned in the well head between the first and second master valves. The hanger assembly is illustrated in detail in FIGURES 2-E through 2-I.

The inner tubing string is secured to and supported from a hanger sub 475, shown in FIGURE 2-D, which is removably engaged in the hanger assembly. The clamp rams 591 of the hanger assembly engage an annular recess 538 on the hanger sub to hold the hanger sub and inner tubing string against longitudinal movement. The longitudinal slot 539 below and connecting with the recess 538 of the hanger sub receives a lug 631 on a ram 590, see FIGURE Z-E, to hold the hanger sub against rotation at the position shown in FIGURE 2-A during handling of the inner tubing string in the procedure of installing the flow control system. The hanger assembly and hanger sub, as will be explained in greater detail hereinafter, are provided with means for forming the seal 441 closing off the upper end of the annular space 44 between the inner and outer tubing strings. A lateral flow passage 450 extends through the hanger assembly into the annular space 44 to allow fluid pressure to be applied through the conduit 451 from the pressure source 452 to -provide the required fluid pressure within the annular space around the subsurface valve for supporting the valve in an open position by holding the weight column in an upward position, as explained in more detail hereinafter. The fluid pressure source 452 is arranged to function responsive to the operational conditions which are monitored and used as the bases for control of the fluid flow control system. For example, it may be desired that the subsurface valve be closed when the pressure within the well head or the flow line 432 exceeds a predetermined maximum. In such event the pressure is monitored by any suitable means so that when the pressure exceeds the predetermined maximum the pressure source 452 is then deactivated permitting the pressure within the annular space 44 to drop allowing the weight column of the subsurface valve to close the valve shutting off flow through the inner tubing string. When the flow control system of the invention is used in connection with an off-shore well having a platform or other well head structure which might be severely damaged by a ship or a barge, the pressure source 452 may be used in conjunction with a detection system for deactivating the pressure source to shut in the well in response to a severe blow sustained by the well platform which might damage or knock off the well head.

A principal component of the fluid flow control system is the subsurface valve assembly 30 illustrated in detail in the FIGURES l-A through l-F and 3 through 26. The subsurface valve assembly includes a telescoping joint 31, a weight or iloating section 32, a detent assembly 33, a flapper valve assembly 34, the ball valve assembly 35, and a lock mandrel assembly 40. The lock mandrel assembly secures the ball valve assembly Within the landing nipple 41 which is a part of outer tubing string 42 through which an inner tubing string 43 extends. The telescoping joint forms a longitudinally slidable connection between the inner tubing string 43 and the floating section so that the floating section may be raised and lowered relative to the inner tubing string to open and close the ball valve. The floating section is supported in an upward position to hold the ball valve opened by a pressure differential between the pressure in the annular space 44 between the inner tubing string 42 and the outer tubing string 43 and the pressure in the flow stream in the tubing string 43. The weight of the floating section biases the ball valve toward a closed position while the pressure of a fluid in the annulus between the inner and outer tubing strings biases the floating section in an upward position to hold the valve open. A decrease in pressure of the fluid biasing the floating section upwardly releases the floating section to impose its weight on the ball valve closing the valve irrespective of and independent of the ambient pressure around the ball valve and weight sections mechanism.

In FIGURES 1-A through l-F, the ball valve is illustrated in open position and the lock mandrel assembly located within the landing nipple but not yet locked in the nipple against upward movement. Referring to FIG- URE l-A, the bottom section of the inner tubing string 43 is threaded to the tubing joint 45 which is suitably secured at the reduced end section 45a to the upper end of the tubular body of the telescoping sections. The connection between the section 45 and the body 50 is made by welding the upper end of the body around the tubing joint at 51 and also by welding the members t0- gether through a plurality of circumferentially spaced holes 52 formed around the body.

An annular piston head 53 is slidably disposed within the body 50 and secured on the upper end of the piston rod 53a by an annular weld at 54 and welds between the floating section and the piston head through a plurality of circumferentially spaced holes 55 extending through the piston head. A port 50d through the body 50 permits the movement of fluids into and out of the body as the piston head reciprocates in the body. The O-ring disposed inthe annular recess 61 of the piston head between the back-up rings 62 and 63 seals between the piston head and the inner wall of the body 50. As will be discussed in more' detail hereinafter, the action of fluid under pressure beneath the annular piston head 53 biases the floating section upwardly to maintain the safety valve in open position.

The lower portion of -the telescoping joint 31 includes an annular retainer assembly 64 engaged in the lower end of the body section 50 to hold the piston head within the body. By so limiting the downward movement of the piston head relative to the body by means of -the stop assembly, the body may be lifted until the upper end of the stop assembly engages the lower end of the piston head at the weld 54 to raise the floating sec-tion and the ball assembly. The stop assembly, as represented in FIG- URSE 1-B, 3, 4, and 5, is segmented to facililtate insertion of the assembly into the body. The assembly consists of the cylindrical segments 65 and 70 having upper outwardly projecting lugs 65a and 70a, lrespectively, as seen in FIGURES 1-B, 3, and 5, and of the cylindrical segments 71 and 72 having the lower outwardly projecting lugs 71a and 72a, respectively, as shown in FIGURES 4 and 5. The segments 65 and 70 are held in the body by engagement of the lugs 65a and 60a and the upper holes 50a and 50b, respectively, while the segments 71 and 72 are retained in the body by engagement of the lugs 71a and 72a, respectively, in the lower holes 50c and 50d, respectively, of the body. Each of the segments is enlarged around its lower end forming an upwardly facing shoulder 73 extending around the assembly engaging the lower end of the -body 50. 'Since the function of the stop assembly is to limit the downward travel of the piston head within the body 50, the several segments of the assembly are loosely fitted with respect to each other and around the floating section to facilitate their insertion into the body.

The piston rod 53a is threaded at lthe lower end into the coupling 74, which is locked to the piston rod by a plurality of the socket set screws 75 radially positioned around the coupling engaging the piston rod as illustrated in FIGURE l-B. The coupling 74 is threaded into the upper end of the weight section 32 comprising a a variable number of the tubular members depending upon the weight required at the operating depth of the valve. The lower end of the weight section is threaded -to the detent section body 81 shown in FIGURES l-B and l-C. A detent collet 82 is loosely positioned within the body 81 to releasably connect the body to the upper end of the -ball valve operator tube 83. The collet is held in the body by engagement of the lower end of the collet with the upper end of the ilapper valve body or cage 84 threaded into the lower end of the body 81. As shown in FIGURE 7, the collet includes the collet fingers 85 formed on the spring section lwhich extend from a base ring 91, thereby allowing the collet fingers to flex both laterally and longitudinally. Each of the collet -ingers has an outer boss 92. and an inner boss 93. The outer bosses extend from the upper ends or shoulders 94 to the lower upwardly and outwardly inclined shoulders 95. The inner bosses 93 are defined by the inwardly convergent upper and lower internal shoulders 100 and 101. Referring to FIGURE l-C, the body 81 has an upper internal annular locking recess 102 between an upper internal annular sho-ulder 103 and the lower internal annular shoulder 104 of an inwardly extending annular flange 105. The lower internal annular locking recess 110 is formed within the body 81 between the downwardly sloping internal annular bottom shoulder 111 of the flange 105 and the upwardly facing internal annular shoulder 112. The valve operator tube is provided with an external annular locking ange 113 between the external annular shoulders 114 and 115. An external annular locking recess 120 extends on the tube 83 between the shoulder 115 and the external upwardly facing annular shoulder 121. The collet fingers cooperate with the recesses and flanges on both the operator tube and within the -body 81 for connecting and disconnecting the lower end of the weight section and the upper end of the operator tube, as will be explained in more detail hereinafter.

The O-ring 122 is fitted within the recess 123 in the body 81 between -the back-up rings 124 and 125 to seal between the inner wall of the body and the outer wall of the operator tube.

As shown in FIGURE l-C, the flapper valve assembly 34 is mounted on the valve cage 84. Referring to FIG- URES 8-11, the apper valve 130 is supported for movement between the full open position illustrated in FIG- URE l-C when the valve is disposed within the circular opening 131 extending through the body 84 and the closed position illustrated in FIGURE 9. The valve is pivotally supported on an arm 132 by a pin 133 extending through the arm and -the parallel spaced longitudinal flanges 134 and 135 formed on the back side of the flapper valve. The arm 132, whose upper end extends into the vertical slot 140 of the valve cage is pivotally connected to the valve cage by a pin 141 which extends through the tangentially oriented hole 142 in the valve body. The apper valve is biased toward the closed position by a spring 143 extending from a hole 144 in the arm through the longitudinal slot 145 to the hole 150 in the valve cage. The opposite ends of the spring are secured in the holes 144 and 150 in a suitable manner, as by friction fit or the like. When the valve is in closed position, as in FIGURE 9, it seats against the Valve seat 151 fitted in the recess 152 of the valve body. The O-ring seal 153 disposed in the annular recesses 154 of the valve seat and 155 of the valve body seals between the valve body and the valve seat. When the inner tubing string including the flapper valve assembly is being run downwardly into a well bore over the upper end of the operator tube, the flapper valve is held in open position by a latch spring 160 disposed in an external annular slot 161 of the valve body. The latch end of the latch spring extends through the slot 162 in the valve body to releasa'bly engage the lower edge of the flapper valve, as illustrated in FIGURE 8, to hold the valve in open position while the tubing string is being run downwardly through ythe well bore and over the upper end of the valve operator tube. The notch 163 in the spring is shaped so that when the valve cage 84 moves over the operator tube 83, the outer surface of the tube will engage the inner face 130a of the flapper valve to displace the valve into the opening 131 and disengage the notch 163 of the lower rim of the valve. Movement of the flapper valve from the position of FIGURE 8 to the vertical position of FIG- ure l-C release the spring from the valve rim. When the apper valve assembly is over the valve operator tube, the external surface o-f the tube holds the flapper valve in the full open outward position within the openinternal annular ange 164 having an upper sloping shoulder 165 and lower sloping shoulder 170 to facilitate movement of the valve body over the valve operator tube.

Referring to FIGURE l-C, the valve operator tube 83 extends through the head member 171 which is threaded into the upper end of the valve housing 172. The operator tube is coupled with the head member by the split ring segments 173 and 174, See FIGURE 12, disposed in the cooperating external annular recess 175 around the operator tube and the internal annular recess within the head member. The recess 180 extends to the lower end of the head member and thus is substantially longer than the recess 174 thereby permitting longitudinal movement of the operator tube relative to the head member while limiting the upward movement of the operator tube so that the head member is lifted by the split rings Iwhen the tube is raised to engage the split rings with annular shoulder 176 of the head member deiining the upper end of the recess 180.

The external annular exible rings 181 and 182 mounted on the upper enlarged head are engageable with the internal surfaces of the external tubing string 41 to form a sand barrier therebetween which prevents sand from accumulating around the lower portions of the latch device by migrating downwardly around the head member of the valve.' An external annular downwardly sloping flange 184 is formed on the head member at the lower end of the head 183 and an upwardly facing external annular ange 185 is formed around the head member below the flange 184. The O-ring is positioned between back-up rings 191 and 192 in internal annular recess 193 within the head member to seal between the inner wall of the head member and the operator tube.

Referring to FIGURES l-C and l-D, the valve operator tube 183 extends downwardly into the valve housing 172 with an enlarged section 194 of the operator tube providing an upwardly facing shoulder 195. A spring 200 disposed around the operator tube engages the lower end of the head member 171 and the shoulder 195 and biases the operator tube in a downward direction. The enlarged bottom section 201, of the operator tube provides an upwardly facing external annular shoulder 202 which engages the bottom annular shoulder of the internal annular iiange 203 of the valve housing to limit upward movement of the operator tube relative to the valve housing.

An upper tubular seat 204 has an upper portion slidably disposed within the lower end of the operator tube. An O-ring 205 positioned between the back-up rings 210 and 211 in the internal annular recess 212 within the lower end of the operator tube 83 seals between the valve seat and the internal surface of the tube. An external annular flange 213 is formed around the lower end of the valve seat and provided with an external annular recess 214. An annular downwardly facing valve seat surface 215 is formed on the lower end of the valve seat 204. An internal annular sleeve 220, see FIGURES l-D and 14, is disposed within the valve housing 172 between the flange 203 and the lower valve seat guide 221. An internal annular flange 222 of the sleeve is received in the recess 214 around the upper valve seat locking the upper valve seat against longitudinal movement within the valve housing. The sleeve is of a resilientsubstance and deforrns outwardly as the upper valve seat is telescoped downwardly thereinto and the external flange 213 thereof moves past the internal ange 222 until the flange 222 moves into alignment with the recess 214. This assembly of the upper valve seat with the sleeve is, of course, performed prior to their insertion into the valve housing 172. A lower valve seat 223 is biased upwardly by a spring 224 disposed around the lower valve seat and between the upper end of the valve seat guide and the lower external annular shoulder 225 of the upper enlarged portion 230 of the lower valve seat. An internal annular upwardly facing seat surface 231 is formed on the upper end of the lower valve seat.

A ball valve 232 disposed betweeen the valve seat surfaces 215 and 231 has a ow passage 233 to permit fluid flow through the subsurface valve assembly when the ball valve is in the open position illustrated in FIGURE l-D. The upper valve seat is held against upward movement by engagement with the ange 222 while the lower valve seat is biased upwardly by the spring 224 causing the ball valve always to be held in engagement with its upper and lower seats. The ball valve is provided with operator holes 234 and 235, see FIGURE 13, which receive the operator knobs 240 and 241 formed on the operator members 242 and 243, respectively. As best illustrated in FIGURE 14, the operator members 242 and 243 are disposed in the longitudinal windows or slots 244 and 245 formed in the sleeve 220. The slots 244 and 245 are each sutliciently longer and wider than the operator members to permit the necessary longitudinal and circumferential or lateral movement of the operator members to rotate the ball valve between open and closed positions. The operator members 242 and 243 are, respectively, provided at their upper ends with the internal flanges 250 and 251 which are slidably received in the external annular groove 252 of the operator tube 83 so that longitudinal movement of the operator tube will raise and lower the operator members to rotate the ball valve. Longitudinal reciprocation of the operator members by the operator tube causes the operator knobs to rotate the ball valve between open and closed positions about the axis 253 as represented in FIGURES 13 and 15-B. The ball valve is rotated between open and closed positions through the angle 254 which is an angle of substantially 90 degrees. During the movement of the ball valve, the operator holes 234 and 23S move a distance L longitudinally and a distance C circumferentially as represented in the FIGURE 15-B. To move the ball valve between open and closed positions, the operator members must move longitudinally the distance L while the operator knob on each of the operator members must follow the arcuate path illustratedin the dotted line portion of the FIGURE l5-B, thus causing the operator members to each move circumferentially the distance C. The flanges 250 and 251 iit suiciently loosely within the recess 252 to permit this circumferential movement of the operator members as they are moved longitudinally to rotate the ball valve. In order for the operator members to move the distance C circumferentially, their flanges must slide in the recess 252 and in so doing, each of the two operator members moves the distance C toward the other member and then away the same distance to rotate the ball valve through the required 90 degrees for moving the ball valve between closed and open position. Each of the operator members will move laterally or circumferentially around the recess through an arc of approximately l degrees while rotating the ball between the open and closed positions. Each of the operator holes moves through an arc of approximately l degrees while the ball rotates between its closed and open positions. The shorter arcs of movement of the operator knobs are due to the facts that when the ball is in its fully open and fully closed positions, the knobs are in outerl positions in the operator holes; and they move farther inwardly into the operator holes as the ball approaches .and reaches a middle position during its movement between its fully open and fully i middle position toward its fully open or fully closed position. Thus, the operator members will converge toward each other and move away from each other a total of twenty degrees during the rotation of the ball valve. It will therefore be obvious that each of the windows 244 and 245 must be wider than the widths of the operator members by substantially l0 degrees of arc or a circumferential distance C and they must be longer than the operator members by the longitudinal distance L in order to contain the operator members and permit their combined longitudinal and circumferential movement during the rotation of the ball valve.

As the ball valve is rotated by the operator members, its longitudinal position within the valve housing remains fixed since the ball valve is biased into sealing engagement with the xed upper valve seat by the force of the spring 224 which urges the lower valve seat upwardly against the ball valve.

The lower valve seat guide 221, which lits within the lower end of the sleeve 220 along an upper reduced section 22111, is held against downward movement by the upper end of the secondary collet housing 253 threaded into the lower end of the Valve housing 172. The upper end section 254 of the housing 253 is reduced in diameter providing the upwardly facing external annular shoulder 255 against which the lower end of the valve housing rests providing a substantially smooth external surface along the connection between the valve housing and the secondary collet housing. The collet housing is threaded on the primary collet lock sleeve 260 as shown in FIGURE l-E with the lower end of the housing engaging the upwardly facing annular shoulder 261 of the lock sleeve. A collet lock mandrel 262 is positioned within the secondary collet housing 253 and the collet lock sleeve 260 as shown in FIGURES lD and l-E with the O-ring 263 positioned in the internal annular recess 264 within the housing 253 between the back-np rings 265 and 270 to seal between the external surface of the upper end of the lock mandrel and the interal annular boss 271 within the housing. An annular split sleeve 272 is disposed around the lock mandrel 262 within the external annular recess 273 of the lock mandrel with upward movement of the sleeve relative to the lock mandrel being limited by the annular shoulder 274 at the upper end of the recess and downward movement of the split sleeve relative to the mandrel being limited by the annular shoulder 275 at the lower end of the recess. As illustrated in FIGURES l-E and 18, the split sleeve ts within the upper end of the lock sleeve 260` to which the split sleeve is secured -by a shear pin 2'80 which releasably engages the split sleeve and lock sleeve. Referring to FIGURES l-D and 17, a secondary collet 281 is secured around the split sleeve 272 by a plurality of shear pins 282 which extend through the base ring 283 of the collet into the split sleeve. An external annular ange 284 around the split sleeve in engagable with the lower end of the base ring of the secondary collet and with the upper end of the collet lock sleeve 260. The collet lingers 2-85 of the secondary collet serve to releasably connect the housing 253 with the lock mandrel 262, the collet lingers being receivable in the internal annular recess 290 within the housing and the external annular recess 291 of the lock mandrel. An annular locking surface 292 is formed around the lock mandrel above the locking recess 291.

As shown in FIGURE l-E, the lock mandrel 262 is reduced along the intermediate section 293 with the reduced section extending from a sloping downwardly facing annular shoulder 294 to a lower external annular should 295, which is at the upper end of the enlarged bottom section 300` of the lock mandrel. A primary collet assembly 30-1 is disposed around the lock mandrel with the major portion of the assembly extending along the reduced portion 29'3. Referring to FIGURES l-E, 19 and 20, the primary collet assembly, which functions to lock the ball valve assembly 35 against upward movement within the landing nipple 41, includes the primary collet 302, which is loosely litted about the lock mandrel and the locking lingers 303 which are formed on and extended downwardly from the lock sleeve 260 around the lock mandrel within the collet. When the device is in locked position within the landing nipple, the locking lingers hold the primary collet in locked position within the nipple. The FIGURES 19 and 20 best illustrate the relationship of the locking lingers with the primary collet. Each of the locking lingers 303 has a thin lower end section 304 extending downwardly from the sloping shoulder 305 formed on the thicker central portion 310 of the locking finger. An internal upwardly facing sloping shoulder 311 is formed on the upper end of each of the enlarged central sections of the locking lingers. The enlarged central section and the lower thin section of the locking lingers are positioned around the reduced section 293 of the locking mandrel so that the shoulder 294 on the locking mandrel and the shoulder 311 on the locking lingers are engageable with each other.

The primary collet 302 in-cludes a plurality of downwardly extending collet ngers 312, each having an outer locking surface or boss 313 which is engageable in the locking recess of the landing nipple. Between each of the collet lingers is a downwardly opening slot 314 while each of the lingers is provided with a slot 315 which opens upwardly through the lbase ring 320 of the collet. A plurality of radially extending ns 321 are formed around the lock mandrel 262 along the reduced section 293. Each of the lins extends into one of the slots 315 formed in each of the collet fingers 312 to hold the collet in the downward position shown in FIGURE l-E. As best shown in FIGURE 19, each of the locking lingers 303 is positioned behind a slot 314 overlapping the inside surface of half of one of the locking fingers and half of the other locking finger adjacent to the slot. Each of the locking lingers may engage half of the inside surface of two adjacent collet lingers. The locking fingers coact with\each other to lock the collet fingers 312 in the landing nipple.

The lock mandrel 262 is reduced along a lower section 323 around which is disposed the packing assembly 324 which is held against upward movement by the downwardly facing annular should 325 on the mandrel. The packing assembly comprises a V-shaped packing 330 and 331 conlined between the male adaptor 332 and the female adaptors 333 and 334.

The lock mandrel 262 is threaded on the lower end to a locator mandrel 335 which supports the selector key assembly 340 which locates the llow control device at the correct position for locking within the desired landing nipple. The selector keys 341 and 342 are supported on the mandrel between the key nut 343 threaded on the mandrel at the lower end of the lock mandrel and the key retainer 344 supported on the mandrel below the keys by the threaded nut 345. The selector keys are biased outwardly by springs 350 engaged between the mandrel and the keys. The keys engage the complementary shaped annular key grooves 351 and 352 within the landing nipple so that the engagement of the downwardly facing selector key shoulders 353 with the upwardly facing landing nipple shoulder 354 prevents downward movement of the device through the landing nipple. The upwardly and inwardly sloping surfaces 355 and the complementary surface 360I within the landing nipple permit upward movement of the device. As eX- plained in more detail in U.S. Patent No. 2,798,559 issued to J. V. Fredd, July 9, 1957, the selector keys perform a locating function permitting the valve assembly to be moved through a tubing string until it arrives at a landing nipple having key grooves corresponding to the conliguration of the outer .surface of the selector keys.

Referring to FIGURE 21. the running tool 370 is shown locked on the operator tube y83 for .lowering the valve assembly downwardly through a well bore to the position for locking the assembly within the landing nipple 41. The running tool includes a tubular body 371 threaded at the lower end on asleeve-like skirt 372 and at the upper end to a head member 373 which hasan upper reduced threaded section 374 for the engagement of a support member 375 suspended from a wire line 380. The ports 373a in the headmember allow fluid ow between the central flow passage through the tool and the exterior so that the tool may be lowered and raised in a fluid filled hole. A retainer ring 381 is secured within the housing above and spaced apart from the skirt by the tangential shear pins 382 which are engaged through the tangential holes 383 through the housing and the tangential semicircular recesses 384 on opposite sides of the retainer ring.

The collet assembly 385 is loosely disposed within the housing above the retainer ring. The collet assembly includes a base ring 390 from which extend a plurality of collet lingers 391 each having a collet head 392 with an outwardly extending boss 393 and an inwardly extending boss 394.

The housing 371 is reduced in internal diameter along a section 400 which is provided with an internal annular seal recess 401 containing an O-ring 401a between the back-up rings 401b and 401C. An internal recess 402 is formed in the housing for receiving the shoulder 114 and the upper portion of the locking liange 113 around the operator tube 83. An upper annular locking recess 403 and a lower annular locking recess 404 are formed within the housing separated from each other by the internal annular locking flange 405. v

The structure of the pulling tool.410 in FIGURE 26 is substantially identical to the running tool with minor exceptions which willbe explained and thus all of the identical parts and `features of the tool have been given the same reference numerals. The shear pins 413 are identical in size to the shear pins 382 and differ therefrom only in the `material of which they are constructed so that their shear strength will be greater. The shear pins 413 generally -will 'be formed of steel or bronze as contrasted with a softer metal such as aluminum which may be used in the shear pins 382. Also, only one shear pin 382 may be used whereas normally two of the shear pins 413 will be employed. The skirt 414 threaded into the lower end of the housing differs from the skirt 372 in the length of the portion of the skirt below the housing since the longitudinal position of the operator tube is lower when removing the flow control devicefrom a well bore as contrasted with its position when running the device into a well bore. In all other respects the same basic tool may be employed for both running and pulling with the proper skirt and shear pins being installed depending upon the function that the tool is to serve.

The polished joint assembly 476 used in installing and Iremoving the weight section and telescoping joint of the subsurface valve and the inner tubing string is illustrated in detail in FIGURES 2-B and ZQC. The polished joint assembly generally comprises a support swivel 477, a valve 478, an elongated, polished,.slidable, tubular .joint 479, and a stuliing box 480 through which the polished joint is slidable. The neck 485 .of the swivelis provided with a hole 486 to receive a supporting hook as shown in FIG. 2-A during installation` or removal of the subsurface valve. The swivel neck extends-:in rotatable relationship through ythe kbushing 487y whichv is threaded into thel connecting member 488 engaged with the upper end of the body 478g of the valve 478. A.thrust bearing ,489 is threaded on the lower end of the swivel neck and locked by the nut 490. The O-rings 495 and 496, separated by the ring 497, are conlined between the upper end of the bearing 489 and the downwardly facing shoulder 498 within the bushing. When the polished joint assembly is suspended as in FIGURE 2-A and weight is placed on the bearing, the swivel neck is pulled upwardly forcing the upper end of the bearing closer to the shoulder 498 causing the O-rings to expand to seal between the bushing and the swivel neck. Upward movement of the swivel neck relative to the bushing is limited by engagement of the bearing sur- -face 499 of the bearing 489 with the lower end of the bushing. A flow passage 500 extends through the swivel neck communicating with the conduit 505 connected into the neck to permit fluid ow into and out of the upper end of the polished joint assembly. The polished joint 479 is secured to the reduced lower end portion 506 of the valve body 478a by the coupling 507. The valve 478 may be any suitable form of valve such as a ball valve which will close off fluid flow or regulate the fluid flow through the body 478:1 below the connecting member 488 and thus through the polished joint assembly.

The stuffing box 480 includes a body member 508 having a downwardly opening annular recess 509 in which the packing 510 is held by the retainer ring 515 threaded into the lower end of the body. The lower end of the body 508 is reduced and provided with an external annular recess 516 in which an O-ring 517 is fitted. A coupling 518 is loosely 4fitted around the body 508 and held against downward movement over the body by the upwardly facing external annular shoulder 519 of the body member 508 which is engageable with the internal flange S20 on the coupling. The coupling is provided with the internal threads 525 for connection over an upwardly extending externally threaded flange 652 on the upper face of a suitable blowout preventer 653, with the inner surface of the flange of the blowout preventer fitting around the reduced lower portion of the body 508. The `O-ring 517 seals between the body and the inner surface of the blowout preventer flange. A coupling 52-6 is threaded on the lower end of the polished joint 479 and held against rotation relative to the joint by the shear pin 527.

The polished joint 479 generally will be from l5 to 18 feet in length to permit the longitudinally maneuverability 4for landing and locking the tubing string in the well bore. The joint 479 is slidable through the stuffing box with downward movement of the member being limited by engagement of the lower end of the coupling 507 with the upper end of the body 508 and upward movement of the tubular member being similarly limited by the engage-ment of the upper end of the coupling 526 with the lower end of the retainer ring 515. The external surface of the joint 479 is sufliciently smooth or polished that the packing 510 forms a seal with the joint as it slides through the stuffing box. The configuration of the elements of the packing cause the packing to expand into tighter relationship both with the inner wall of the recess 509 and with the external surface of the joint 479 when the packing is subjected to a pressure from below between the retainer ring and the surface of the joint.

The hanger sub 475, as shown in FIGURE 2-D, is a tubular member which may be landed and locked within the hanger assembly 440 to support the inner tubing string 43 within the well bore. The sub is engageable on the lower end of the polished joint assembly for handling the tubing string in carrying out certain steps of installation and removal of the tubing string. The internal threads 535 at the upper end of the sub are engageable with the lower threaded end of the coupling 526 on the lower end of the polished joint assembly while the external threads 536 at the lower end of the sub permit connection with the upper end of a tubing string. The sub is reduced in diameter along a lower section 537 below and spaced apart from an external annular recess 538. A longitudinal slot 539 is cut into the surface of the sub extending from the reduced section 537 upwardly into the recess 538. An O-ring 540 and a back-up ring 545 are positioned in a lower external annular recess 546 and an O-ring 547 and a back-up ring 548 are similarly positioned in an upper external annular recess 549 around the sub.

A back-pressure valve assembly 550 is engageable in the upper end of the hanger sub to permit downward ilow through the sub while preventing upward flow. The backpressure valve may be threaded into and removed from the sub by means of the two pronged collet 555. The body 556 of the back-pressure valve is provided with an external O-ring seal 557 around the body below the external threads 558. The body is reduced in diameter along a lower end section 559 below the radial ports 560 connecting into the valve chamber 561 at the lower end of the longitudinal flow passage 562. The back pressure valve body is reduced in diameter above the shoulder 563 and provided with a laterally extending slot 564 which permits fluid flow into the upper end of the bore 562 and receives the inwardly extending collet linger bosses 565 so that the collet may grip the body of the valve and rotate the body for threading it into and out of the hanger sub. A spring retainer 565 having a bore 565a is threaded into the lower end of the valve body to support the spring 570 and the ball valve 571. A downwardly facing annular valve seat 572 is formed around the bore 562 to permit the ball valve to close off upward flow into the bore. Flow from above the ball valve causes the ball to move downwardly against the resistance of the spring allowing uid to ow around the ball through the chamber 561 and the ports 560 downwardly around the reduced lower end section of the valve body into the bore 575a through the hanger sub. The biasing effect of the spring 570 maintains the ball on seat 572 together with an upwardly acting pressure differential across the ball to prevent upward ow through the valve so that the valve will hold a back pressure Within a tubing string supported from the hanger sub. The back-pressure valve is inserted by the collet to the position shown in FIGURE 2-B only when certain operational conditions require the holding of a back pressure within the tubing string to which the hanger sub may be engaged.

The hanger assembly 440 includes a body 580 which is formed in the shape of a cylindrical segment having a plurality of radially positioned, axially extending bores 581 which permit the master valves 424 and 425 to be bolted to the bottom and top faces of the body. The body 580 may be formed from a standard type flange used in certain oil field production tools so that the hanger assembly may be secured with standard types of master valves having similar flange bodies. The seal recesses 582a and 582b are formed in the upper and lower faces, respectively, of the body to receive ring type seals to seal between the hanger assembly body and the adjacent bodies of the master valves. A radiallly extending bore 450 opens into an axial central bore 583 through the body. The radial bores 584 and 585 extend along a common axis perpendicular to the radial -bore 450 and the axial bore 583 and intersecting the axial bore. The lug ram 590 in the bore 450 and the clamp rams 591 in the bores 584 and 585 cooperate to support the hanger sub and hold the sub against rotation in the hanger assembly. The outer end of the bore 450 is connectable with the conduit 451 as shown in the FIGURES 2 and 2A.

The clamp ram assemblies 591 in the bores 584 and 585 are identical in structure. The clamp ram 592 of each clamp ram assembly is provided at its inner end with an arcuate toothed section 593, the length of which permits the toothed surface to be received within the annular recess 538 of the hanger sub 475 to provide Vertical support to the sub within the hanger assembly. A locking spring slot 594 extends laterally across the clamp ram near the inward end thereof. The internally threaded bore 595 extends into the ram from the outward end to receive the jack screw 600 for moving the clamp ram in the bore 584 into and out of locking relationship with the hanger Sub. A lateral vent port 601 extends through the clamp ram into the inward end of the bore 595 to allow entry and exhaust of uid from the bore 595 as the jack screw is rotated relative to the clamp ram. The jack screw is rotatably positioned through a packing gland 602 and the gland nut 603. An O-ring 604 and a back-up ring 605 are fitted within the packing gland -around the jack screw to seal between the jack screw and the gland. An O-ring 610 around the packing gland seals between the gland the Surface of the bore 584. The packing gland is held against inward movement by the annular flange 611 formed around the gland. A bearing flange 612 is formed around the jack screw fitted within the gland nut at the outward end of the gland to hold the jack screw against movement along its longitudinal axis while being rotated to move the clamp ram into and out of locking position. The outward end of the jack screw is provided with the ilat surfaces 613 to permit engagement of a wrench with the jack screw for rotating the screw.

The lug ram 590 is retained within the bore 450 in the position illustrated in FIGURE 2E by the spring 620 which encircles the bore 583 of the hanger assembly body passing through the recesses 594 at the inward ends of the clamp rams. The end portions 620:1 and 620b of the spring are received in the slot system 621 formed along the top of the lug ram. The mid portion 620C of the spring is wider than the end portion along the dimension parallel to the axis of the bore 583 to increase the strength of the spring.

The configuration of the lug ram is best understood by reference to the enlarged FIGURES 2-G through 2-1. The slot Sytem 621 serves a dual function of providing iluid communication through a portion of the ram while also cooperating with the spring 620 to move the ram inwardly and outwardly within the bore 450. The unusual configuration of the slot system is largely a result of machining expediency to achieve the two objectives of the system to provide the needed uid ow paths and the necessary camming surfaces against which the spring acts to move the lug ram. rI`he elongated slots 622 and 623 provide fluid communication through the ram from the inward end of the ram into its bore 624 which extends into the ram over about one half the length of the ram, as illustrated. The slots 622 and 623 also provide the cam surfaces 622:1 and 623a. The shorter slots 625 and 630 provide the cam surfaces 625a and 630a, respectively. A lug 631 having an arcuate inner face 631a is formed on the inward end of the lug ram to cooperate with the longitudinal slot 539 in the hanger sub to hold the hanger sub against rotation within the hanger assembly. The lower end of the lug 631 slopes upwardly and outwardly along the surface 631b. It will be readily understood that the slot system in the lug ram, due to the cylindrical configuration of the ram can be cut with standard milling tools by basically cutting the two long and two short slots previously described. The long slots 622 and 623 intersect the bore 624 to provide communication through the length of the ram. Obviously, the bore 624 can not extend entirely through the ram because of the need for material to form the lug 631 on the inward end of the ram. The triangular segment of the ram, two sides of which form the surfaces 625a and 630a, in cut olf along its top forming the ilat surface 632.

The lug ram is moved into and out of locking position within the bore 450l by the action of the ends 620a and `620b of the spring which are expanded and contracted -by the movement of the clamp rams within the bores 584 and `585. In the position illustrated in FIGURE 2 E the lug ram is held inwardly by the spring so that the lug 631 is engaged in the longitudinal recess 539 of the hanger sub `475. The lug ram is retracted sufficiently to disengage the lug from the longitudinal recess of the hanger sub by retracting the clamp rams 591 by rotation of the jack screws. As the clamp rams retract, the surfaces 594a of the clamp rams defining the inner sides of their slots 594 engage the inner surfaces of the portions of the spring 620 extending through these slots and, as both of the clamp rams are retracted or drawn away from the hanger sub, the spring is spread apart moving its end portions I62011 and 620b away from each other. The spring end 620b acts against the surface 623a while the spring end -620a acts against the surface 622a of the lug ram causing the ram to be moved downwardly until the lug 631 is no longer engaged in the recess 539. When the clamp rams are moved inwardly in the bores 584 and 585 the back faces 594b of the slots 594 engage the outer surface of the section of the spring 620 through each of the rams causing the end portions 62011 and 620b of the spring to be rnoved closer together. As the spring end portions move closer together the inner surfaces of the spring end portions act against the cam surfaces 625a and 530a of the lug ram to cam the lug ram inwardly so that the lug 631 will be biased inwardly and may be received in the longitudinal recess 539' of the hanger sub. A further important feature of the slot and spring arrangement as shown in connection with the lug ram is that due to the generous tolerance in the slot 594 between the inner and outer surfaces 594a and 594b defining the slots, the clamp rams 591 may be retracted sufficiently to withdraw the inward ends of the rams from the annular recess 538 of the hanger while the lug 631 is biased inwardly by the spring so that the hanger sub may be rotated and moved longitudinally until the lug is snapped by the spring ends into locking position in the slot 539. In other words, the spring will permit the lug ram to be held outwardly with the lug 631 being engaged with the outer surface of the hanger sub at a location on either side or above or below the slot 539 and the hanger sub 475 may be rotated and moved longitudinally while hunting for the proper position and when such position is reached the spring biased lug ram will snap inwardly with the lug properly moving into the slot 539 to hold the sub against rotation while the polished joint assembly is threaded into or out of the upper end of the sub.

Referring to FIGURE 2-F, the axial bore 583 through the body 580 of the hanger assembly is enlarged along a lower section 583a, is enlarged along an intermediate section 583b, and is still further enlarged along an upper section 583e with an upwardly facing shoulder 583d being formed at the juncture of the sections 583b and 583e. A seal sub 640 is supported within the bore 583 to provide a sealing surface engaged by the O- rings 540 and 547 of the hanger sub when the hanger sub is locked in its proper position within the hanger assembly. The seal sub is reduced in diameter along a lower section `640a to tit within the section 583b of the bore through the body 580. The upper section of the seal sub 640b is enlarged to fit within the section 583C of the bore. The external annular shoulder 640e around the seal sub seats on the shoulder 583d within the bore. The lower ring seal 641 and the upper ring seal 642 are engaged in annular recesses around the seal sub. The lower ring seal seals between the body 580 and the seal sub in the bore 583C. The upper ring seal seals within the bore of the master valve 425 35 are landed and locked in place as a unit within-the. tubing string, followed by the detent assembly 33 and the,-

llapper valve assembly 34, the oating weight section 32, and the telescoping joint. The detent assembly,'the flapper valve assembly, the weight section, and the telescopingjoint are lowered as a unit on the lower end of the inner tubing string `43- and engaged with the valve assembly by latching the detent assembly vover the upper end of the operator tube 83 of the valve assembly.

A well in connection with which the flow control system of the invention is to be installed must be equipped with the landing nipple 41 to provide the means for landing and locking the subsurface valve assembly in position within the well bore. The landing nipple may have been installed in the tubing string 42 upon initial completion of the well. If, however, the landing nipple was not so installed, standard oil iield procedures are used to pull the tubing string, connect the landing nipple in the string at the proper position, and run the string back into the well and secure it in position as illustrated in FIGURE 2. The well head 423 is made up with the necessary units for installation and operation of the flow control system. The well head includes the first and second master valves 424 and 425 on either side of the hanger assembly 440 which s provided with the previously described means or hanger sub `475 for hanging and packing off the inner tubing string 43 and connecting the fluid pressure conduit 451. The iirst and second master valves are suitable commercially available valves having the standard flanges permitting interconnection with the body 580 of the hanger assembly. The pressure source 452 is conected into the hanger assembly 440l through the conduit 451. If the well in which the system is being installed is one which is already producing and has a landing nipple 41 within its tubing string, it is not necessary to kill the well; i.e., till the well with liquid suiiiciently heavy to stop it from producing, in order to carry out the installation procedure. It is, of course, necessary that -ow through the well be temporarily suspended to permit properly equipping the Well head. This may be done by use of conventional wireline equipment to install a plug choke as illustrated at page 3737 of the Composite Catalogue of Oil Field Equipment Services 1964-65 edition, published by World Oil, Houston, TeX. With flow temporarily suspended in the well, or if the well is not flowing and thus does not require the plug choke, the well head is equipped with the first and second master valves and the hanger assembly above described. The well head also includes the T connection 431 on top of which is installed the swab valve 430.

If the flow control system is being installed in a well which is being initially completed the well should be brought in, tested, and allowed to clean up prior to the steps of installing the subsurface valve. If desired the tubing can be loaded, that is, iilled with a liquid, to lower the shut-in pressure of the well but every eiort should be made to eliminate trapping dirty or corrosive fluids in the annulus 44 when landing and locking the inner tubing string on the subsurface valve.

To prepare the Well head for installation of the subsurface valve assembly 35 and the lock mandrel 40 conventional wireline equipment is made up on the well head with the equipment being secured on top of the swab valve 430 after the flange 433 has been removed. Such wireline equipment includes a lubricator, a stuing box, and other related apparatus as illustrated and described at page 3741 of the Composite Catalogue of Oil Field Equipment and Services, supra.

If a plug choke is in the landing nipple it must be removed before the valve assembly and lock mandrel can be landed. The tubing should be filled with water or oil and raised to shut-in pressure after which the plug choke is retrieved by standard wireline procedure.

In order to prepare the valve assembly and lock mandrel for insertion into the lubricator -from which they are lowered to the landing nipple they are first interconnected in the relationship illustrated in FIGURES l-D and l-E by threading the head 271 into the lower end of the housing 172. The running tool 370 is employed on the valve assembly for actually lowering the valve assembly and lock mandrel through the well bore. In assembly of the lock mandrel, the collet 281 and related members are positioned as shown with the shear pins 280 and 282 installed to hold the units in the relationship where the collet lingers 285 are engaged in the locking recess 291 around the collet lock mandrel 262. Also the collet lock lingers 303 are held -by the shear pin 280 in the relationship shown in FIGURE l-E while running the devices into the well. The running tool 370 is latched over the operator tube 83 of the valve assembly as shown in FIG- URE 2l. The running tool is placed over the upper end of the valve operator tube with the operator tube moving into the running tool to the position shown in FIGURE 24 where the locking flange 113 moves into contact with the internal recess 402 with the locking flange camming the collet heads 392 outwardly into the annular recess 403 to allow the locking flange to pass to the position shown where the collet finger heads will move past the shoulder on the lower end of the locking ilange. The collet assembly 385 is loosely fitted within the housing 371 and around the operator tube so that the collet assembly may move upwardly with the operator tube to the position where the collet heads will move outwardly into the recess 403. With the relationship between the valve operator tube and the running tool shown in FIG- URE 24, the collet finger heads are positioned to where they may be cammed inwardly to engage the shoulder 115. The running tool is lifted so that the internal annular ange 404 engages the bosses 393 on the collet linger heads to Ltorce the heads inwardly around the operator tube into the locking recess with the upper ends 0f the collet linger heads engaging the shoulder 115 to support the operator tub'e and thus permit the valve assembly and lock mandrel assembly to hang from the running tool on the collet lingers. The running tool is lifted with the flange 405 moving into alignment with the bosses 393 on the collet finger heads to hold the collet linger heads in the recess 120 of the operator tube as illustrated in FIGURE 21. The spring 200 biases the Operator tube downwardly and, therefore, the ball Valve 232 toward a closed position. When the lock mandrel and valve assemblies are suspended from the running tool, the lock mandrel and the valve housing 172 are urged downwardly by their weight in opposition to the biasing force of the spring. This weight may be sufficient to hold the valve housing downwardly relative to the operator tube to keep the ball valve in the open position so that fluid may flow freely through it as the lock mandrel and valve are lowered into position in the tubing string. In the event, however, that the spring 200 is so strong that the weight of the lock mandrel assembly and the safety valve housing will not hold the ball valve in open position, the skirt 372 on the running tool is of sufficient length that its lower end will engage the upper end of the head 183 on the head member of the valve housing so that the operator tube of the valve is held upwardly relative to the valve housing at a position which will maintain the ball valve at least partially open to the degree necessary to allow Well fluids to flow through the valve as it is lowered through the tubing string.

The lock mandrel and valve are lowered from the lubricator through the tubing string 42 until the lock Vmandrel reaches the landing nipple 41. The landing nipple 41 may be one of several in the tubing string, particularly if a plurality of Valves are to be installed in the string. Whether the landing nipple 41 is one of several or the only landing nipple in the string, the key grooves 351 and 352 of the landing nipple conform to the shape of the selector keys 341 and 342 so that when the lock mandrel reaches the landing nipple 41, the selector keys will be expanded by the springs 350 into the key grooves with the landing nipple shoulder 354 engaging the selector key shoulders 353 to provide support for thelock mandrel and prevent its further movement downwardly. The selector keys thus provide a means for locating the lock mandrel in the proper landing nipple and give Vertical support to the lock mandrel.

During the lowering of the lock mandrel and valve assembly through the tubing string, the well fluids in the tubing string move through the central ow passage ex-

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