US3848629A - Low flow safety valve with pressure lock - Google Patents

Low flow safety valve with pressure lock Download PDF

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Publication number
US3848629A
US3848629A US00302545A US30254572A US3848629A US 3848629 A US3848629 A US 3848629A US 00302545 A US00302545 A US 00302545A US 30254572 A US30254572 A US 30254572A US 3848629 A US3848629 A US 3848629A
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Prior art keywords
valve
pressure
responsive
flow
inner member
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Expired - Lifetime
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US00302545A
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English (en)
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D Young
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Schlumberger Technology Corp
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Schlumberger Technology Corp
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Priority to US00302545A priority Critical patent/US3848629A/en
Priority to CA184,292A priority patent/CA991077A/en
Priority to GB5017273A priority patent/GB1447993A/en
Priority to FR7338420A priority patent/FR2204768B1/fr
Priority to DE19732354275 priority patent/DE2354275A1/de
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    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B34/00—Valve arrangements for boreholes or wells
    • E21B34/06—Valve arrangements for boreholes or wells in wells
    • E21B34/08—Valve arrangements for boreholes or wells in wells responsive to flow or pressure of the fluid obtained
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/7722—Line condition change responsive valves
    • Y10T137/7723—Safety cut-off requiring reset
    • Y10T137/7726—Responsive to change in rate of flow
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/7722—Line condition change responsive valves
    • Y10T137/7723—Safety cut-off requiring reset
    • Y10T137/7731—Fluid counter-biased or unseated valve
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/7722—Line condition change responsive valves
    • Y10T137/7723—Safety cut-off requiring reset
    • Y10T137/7731—Fluid counter-biased or unseated valve
    • Y10T137/7733—With fluid pressure seating of valve

Definitions

  • a safety valve for installation down hole in the production string of an oil well includes a housing having a valve head disposed in fixed relation thereto.
  • An actuator sleeve is disposed within the housing and cooperates with the housing structure to define a flow passage through the valve mechanism.
  • the actuator sleeve is moveable linearly within the housing between open and closed positions and carries a valve face that is engageable with the valve head in the closed position thereof to interrupt the flow of fluid through the flow passage of the valve.
  • the actuator sleeve is moveable to the closed position thereof upon reduction of the rate of flow through the valve below a predetermined minimum and, once closed, is maintained in the closed position by pressure upstream of the valve.
  • the safety valve includes selectively actuatable means for modifying the pressure responsive means and thereby allow formation pressure to move the actuator sleeve to the open position thereof.
  • This invention relates generally to control valves used in well installations, and more particularly to a down hole safety valve mechanism having a facility for interrupting the flow of production fluid in the event the rate of fluid flow falls below a predetermined minimum and for preventing automatic reopening of the valve mechanism in the event formation pressure conditions should subsequently increase to a level that would again establish a normal rate of flow.
  • velocity sensitive safety valve mechanisms capable of shutting in the well in the event velocity should exceed a predetermined maximum. This condition of course may occur in the event of failure of surface valves of the production system of the well, in the event of rupture of a production flow line or in the event of any other failure that might allow a relatively unrestricted flow of fluid through the tubing string.
  • a decrease in velocity may represent the development of an undesirable condition in the formation produced by the well or might indicate the existance of an abnormal condition in the down hole production equipment of the well. It is desirable, therefore, to cause production of fluid to cease in the event any abnormal condition is sensed and to maintain the well production equipment in a safe closed position, even though operating conditions may be restored, in order that tests may be performed to determine the cause of the abnormal flow condition.
  • a velocity sensitive safety valve should automatically close, even for an instant, responsive to the development of excessive flow in a well production system, it may be desirable to provide a secondary safety valve mechanism that is sensitive to the decrease in flow caused by closure of the velocity sensitive system. This feature would, of course, allow a safety valve mechanism to shut in the well, even though the velocity sensitive valve might not be sufficient, acting alone, to completely shut in the well and maintain the well system under a safe closed condition until the well production system may be repaired or otherwise restored to the proper operating condition thereof.
  • lt is therefore a primary object of the present invention to provide a novel safety valve mechanism for a down hole well environment which is effective to close, thereby completely shutting in a production system of the well, in the event the rate of flow of production fluid through the valve mechanism should fall below a predetermined minimum level.
  • a novel safety valve mechanism for a down hole well environment including means for insuring positive, but selective reopening of the valve mechanism after closure thereof.
  • the present invention is directed to the provision of a down hole safety valve mechanism that is maintained in an open or flowing condition thereof by a resultant force developed by pressure differential caused by the flow of fluid across a choke bean, which resultant force is greater than the force developed by a compression spring urging the valve mechanism toward the closed position thereof.
  • the valving mechanism of the safety valve may comprise a valve head, maintained in stationary relation to the housing structure, and a valve face, carried at the lower extremity of an actuator sleeve assembly or mandrel and being disposed for engagement with the stationary valve headto interrupt the flow of fluid through the valve mechanism.
  • the actuator sleeve assembly may be urged by a compression spring toward the closed position thereof and may be maintained in the open position by a resultant force developed by the flow of production fluid across a choke element carried within the mandrel. Upon the development of an abnormally low flow rate, the actuator sleeve assembly or mandrel will be moved to the closed position thereof by the compression spring.
  • the actuator sleeve assembly becomes pressure sensitive in a manner causing the valve mechanism to be maintained in the closed position thereof responsive to the development of a net closing force developed by formation pressure down-stream of the valve mechanism and acting against differential surface areas.
  • Means may be provided for selectively modifying the pressure sensitive nature of the actuator sleeve by balancing the pressure responsive surface areas and thereby conditioning the valve mechanism for reopening responsive to formation pressure.
  • a mechanism may also be provided to prevent the valve assembly from moving immediately to a reclosed position, subsequent to opening, if the rate of flow across the choke bean is insufficient to produce a force of a magnitude necessary to overcome the force of a valve closing compression spring that urges the valve mechanism toward the closed position thereof at all times.
  • FIG. 1 is a pictorial representation illustrated partially in section of a subsurface earth formation having a well bore extended therethrough and being lined with a well casing including a production tubing containing a down hole safety valve mechanism constructed in accordance with the present invention.
  • FIG. 2 is a fragmentary sectional view of the well casing structure of FIG. 1, illustrating a typical landing nipple and showing wire line emplacement and retrieval apparatus having a safety valve mechanism constructed in accordance with the present invention connected to the lower extremity thereof.
  • FIGS. 3A and 3B are sectional views of the upper and lower portions, respectively, if the safety valve mechanism of the present invention, illustrating the moving parts in the normal fluid producing positions thereof.
  • FIG. 4 is a fragmentary sectional view of the valve mechanism of FIGS. 3A and 3B, illustrating the valving mechanism thereof in the fully closed position.
  • FIG. 5 is a sectional view taken along line 5-5 in FIG. 4.
  • FIG. 6 is a sectional view of the lower portion of the safety valve mechanism of the present invention illustrating the moveable parts of the valve mechanism in the disarmed and flowing condition thereof.
  • FIG. 7 is a sectional view of the lower portion of the valve mechanism of the present invention showing the condition of the moveable parts of the valve mechanism in the disarmed and closed position thereof.
  • FIG. 8 is a sectional view of the lower portion of the safety valve mechanism of the present invention illustrating the moving parts thereof in the armed and closed position thereof immediately preceeding opening movement of the valve mechanism.
  • FIG. 9 is also a sectional view of the lower portion of the valve mechanism of this invention illustrating the moveable parts thereof in the armed and opening condition.
  • FIG. 1 an earth formation is illustrated at 10 having a well bore 12 drilled therein which is lined with a well conduit 14 that may be cemented in place in conventional manner.
  • Production tubing 16 typically referred to in the industry as a tubing string, extends through the well casing 14 and is sealed with respect to the well casing by a packer 18 located a convenient distance above the production zone of the earth formation.
  • the tubular conduit 16 is open at its lower extremity to production fluid flowing through perforations in the casing 14 and conducts the production fluid upwardly through the tubing string in conventional manner.
  • safety valve mechanism For the purpose of shutting off the flow of production fluid through the tubing 16 in the event production flow in the tubing should increase or decrease abnormally, it will be desirable to provide a safety valve mechanism that is responsive to predetermined decrease in the flow of production fluid to close and effectively shut off the flow of fluid.
  • such safety valve mechanism may conveniently take the form illustrated in the drawings where a safety valve mechanism is depicted generally at 20 that may be installed and removed by conventional wire-line equipment, illustrated generally at 22. It will be convenient to install the safety valve within the tubing string at a level where the temperature is high enough to prevent solidification of paraffin which might otherwise cause fouling of the moveable valve parts.
  • the wire-line apparatus 22 is shown to include a landing nipple 24 that may be provided with externally threaded extensions 25 and 26 that receive internally threaded extremities of the production tubing 16.
  • An annular landing shoulder 28 may be defined within the lower extension 26 of landing nipple 24 for engagement by an annular shoulder 30 formed on a wire-line tool 32, thereby preventing the wire-line tool from descending below the level established by annular shoulder 28.
  • Wire-line tool 32 may be provided with locking detents 34 adapted to be received within an annular locking groove 36 defined within landing nipple 24.
  • Wire-line tool 32 may also be provided with a packing 38 of annular configuration for engagement with the cylindrical surface 40, defining a portion of the receptacle for the wire-line tool. As is typically the case, wire-line tool 32 may also be provided with a fishing neck 42 at the upper extremity thereof that may be engaged by appropriate installation and retrieval apparatus of conventional nature.
  • wire-line installation and retrieval apparatus 32 is illustrated in FIG. 2, it is to be understood that the particular configuration illustrated is not intended to limit the present invention. It is intended to be obvious that any suitable wire-line tool of conventional nature may be employed within the spirit and scope of the present invention.
  • the wire-line tool 32 may be provided with a lower externally threaded extremity 44 adapted for threaded connection to internal threads 46 formed within the upper sub 58 of an upper housing section 60 of the safety valve mechanism 20, thereby effectively supporting the safety valve in depending relation from the wire-line tool 32.
  • the safety valve mechanism illustrated generally at may comprise an outer housing, illustrated generally at 52, that is of generally tubular configuration.
  • the internal threads 46 of the upper sub may establish threaded connection to a wire line tool such as illustrated at 32 in FIG. 2, generally referred to as a setting mandrel, or may establish connection of the safety valve mechanism to a section of tubing carried by the wire line tool or setting mandrel depending upon design parameters of the production system of the well.
  • the housing structure 52 may be defined by an upper housing section 60 and an intermediate housing section 62 that are joined by a coupling element 64 having an intermediate thickened wall section and having upper and lower threaded extremities 66 and 68 for threaded engagement with the upper and intermediate housing sections, respectively.
  • the intermediate housing section 62 maybe provided with an externally threaded lower extremity 70 that may be threadedly received by internal threads 72 defined within a lower housing section 74.
  • the lower housing section may likewise be provided with internal threads 76 adapted to receive an externally threaded extension 78 of a lower sub 80, defining the lower extremity of the valve mechanism.
  • a plurality of passages, such as shown at 82 and 84 in FIG. 38, may be bored or otherwise formed in the lower sub 80 and may communicate pressurized production fluid from the formation into the tubular valve housing 52.
  • valve actuator assembly also referred to as a mandrel, illustrated generally at 86
  • mandrel a valve actuator assembly
  • FIGS. 3A and 3B where a valve actuator assembly, also referred to as a mandrel, illustrated generally at 86, may be disposed for reciprocal movement within the housing structure 52 and may carry a valve face-element at the lower extremity thereof for valving engagement with a valve head carried in fixed relation to the valve housing.
  • the valve face element and the head portion of the valve structure are described in detail hereinbelow.
  • the valve actuator assembly 86 may comprise an upper tubular section 88 having an enlarged flange portion 90, disposed at the lower extremity thereof and provided with internal threads 92, for engagement with the externally threaded portion 94 of a lower tubular section 96.
  • An urging means for imparting a force to the valve actuator assembly 86 and urging the same towards a position causing the valving assembly to close may comprise a compression spring 98 disposed about the upper tubular section 88 and interposed between shoulders 100 and 102 defined, respectively, by the lower extremity of the coupling element 74 and the upper annular surface of the enlarged flange portion 90 of the upper tubular section 88.
  • One suitable means for protecting the valve mechanism from the abrasive or interference problems created by production of sand along with the well fluid may conveniently take the form of a thin walled tubular element 104 provided with a lower internally threaded extremity 106 and being received by an externally threaded upper extremity 108 of the upper tubular section 88 of the valve actuator assembly.
  • the thin walled tubular element 104 may be adapted to receive a smler thin walled sleeve 110 which may depend from the upper sub 58 and may be disposed concentrically and in spaced relation within the outer thin walled section 104.
  • This arrangement provides a substantial dead fluid space or gravity barrier to prevent sand gains or other abrasives in production fluids from contacting any sealing surfaces of the valve mechanism or settling on top of a piston, to be described hereinbelow, and interfering with the sealing ability of sealing elements carried by the piston.
  • This particular arrangement has been found to provide a substantial protection against surface galling and seal failure.
  • the lower tubular section 96 of the valve actuator assembly or mandrel 86 may be provided with a lower externally threaded extremity 112 disposed in threaded engagement with internal threads 114 provided on a valve face element 116 having an enlarged or flared lower portion 118 defining an internal annular sealing surface 120 anda tapered seat shoulder 122.
  • a stationary valve head portion of the valving mechanism may comprise a valve head base structure 126 formed integrally with or disposed in fixed relation to the structure of the lower sub 80.
  • the valve head portion 124 may be provided with an annular resilient seal element 128 that may be sandwiched between upper and lower retainer rings 130 and 132 to form a seal assembly.
  • the seal assembly may be retained in assembly with the base portion 126 of the valve head by a retainer post element 134 having external threads received by internal threads defined within a blind bore 135 of the post.
  • the annular seal element 128, along with the retainer ring 130 and 132, may be disposed relative to the valve face portion 116 as to be received in sealing engagement within the annular generally cylindrical seal surface 120 to the extent that an annular tapered surface 136 defined on the upper retainer ring 130 may move into abutting relation with the tapered annular surface 122, thereby defining a secondary or metal-to-metal seal.
  • annular sealing element 128, which, for example, may be composed of a wear resistant material, such as polytetrafluoroethylene, may be compressed slightly as a force is applied by the head portion 116 of the actuator sleeve through the tapered surfaces 122 and 136, thereby causing the outer periphery of the sealing element to expand slightly and develop tighter sealing contact with the surface 120.
  • the elastic memory of the seal material will contract the outer periphery of the seal element back to the original slight interference fit with the cylindrical surface 120.
  • valve actuator assembly or mandrel 86 is normally urged downwardly by the compression spring 98 to a position closing the valving assembly. It is desirable, therefore, that velocity sensitive means be provided to maintain the mandrel in an upper position thereof against the force developed by the compression spring in order to maintain the valving mechanism in the open position thereof to allow normal flow of fluid through the safety valve.
  • velocity sensitive means may conveniently take the form of a choke bean 138 having a restricted flow orifice 140 defined therein.
  • the choke bean 138 although typically composed of an extremely hard and wear resistant material, will become worn after a period of time, because of the abrasive action of sand and other foreign matter being carried along with production fluid flowing through the orifice 140. It is desirable, therefore, to provide a choke bean structure that may be readily replaced without difficulty.
  • An upper choke retainer element 142 may be received in abutment with the lower annular surface of the lower tubular section 96 of the mandrel and may provide downstream support for the choke bean.
  • a threaded retainer element 144 may be received by internal threads formed within the face portion 116 and may provide upstream support for the choke bean.
  • the choke bean may be removed from the face portion 116 simply by unthreading the retainer element 44 and extracting the choke bean from engagement with the upper retainer element 42. Access may be gained to the threaded retainer 144 and choke bean 138 simply by unthreading the lower sub 80 from the lower housing section 74. Replacement or repair of other portions of the valving assembly can logically be accomplished in similar manner without complete disassembly of the safety valve mechanism.
  • the rate of flow of production fluid through the valving mechanism should decrease below a predetermined minimum level, determined by the magnitude of the force necessary to compress the spring 98, the force developed by pressure differential across the choke bean 138 will be insufficient to overcome the compression of the spring 98 and the spring will drive the mandrel 86 downwardly, causing the face portion 116 of the valving mechanism to move the seal surface 120 into receiving relation with the annular sealing element 128, as shown in FIG. 4, and the flow of production fluid through the valving mechanism will be effectively interrupted.
  • valve mechanism upon closure of the valving mechanism, to cause the valving mechanism to remain in the closed position thereof to prevent further flow of production fluid even though conditions may be effectively restored for establishment of normal flow. For example, formation pressure may decrease momentarily due to development of some unusual well condition and the valve may close. If the valve mechanism were capable of being opened responsive to restoration of normal operating pressure, the valve would reopen and produc tion flow would begin without allowing production personnel to detect the abnormal pressure condition and a dangerous well condition could develop. It is, therefore, desirable to construct the valving mechanism in such manner that it will remain open responsive to fluid flowing above a predetermined minimum velocity and, after becoming closed, responsive to decrease in velocity below a predetermined minimum rate of flow, the valve mechanism will be maintained in the closed position thereof responsive to formation pressure. In other words, the valve mechanism is desired to be velocity sensitive in the open condition thereof and is desired to be pressure sensitive in its closed position.
  • the area of the mandrel that is acted upon by formation pressure and develops a force tending to move the valving mechanism to the open position thereof is illustrated by dimension Al.
  • the area of the valving mechanism acted upon by formation pressure and developing a force tending to close the valve mechanism is illustrated by dimension A2.
  • the area A2 is substantially larger than the area Al defining a resultant area R,
  • valve mechanism Once the valve mechanism has become closed, therefore, it will be necessary to institute a particular reopening procedure for opening the valve and placing the production system of the well back on flow.
  • This feature allows production personnel to detect unusual well conditions and conduct tests to determine the reason for the abnormal flow condition.
  • One suitable means of accomplishing the valve reopening procedure can effectively be accomplished by selective alteration of the pressure responsive areas of the valve actuator assembly or mandrel 86, to allow formation pressureto open the valve and allow resumption of flow across the choke bean 138.
  • One suitable means for selectively altering the pressure responsive areas of the mandrel may conveniently take the form of a piston 146 the annular area A3 of which is larger than the area R (difference in areas A1 and A2), illustrated in FIG.
  • the piston element 146 may be provided with inner and outer annular sealing elements 148 and 150 respectively, which may conveniently take the form of O-rings or any other suitable sealing devices, for engagement with sealing surfaces 152 and 154 defined on the lower tubular section 96 and lower housing section 74, respectively.
  • a means for achieving interlocking of the piston with the mandrel may conveniently take the form of a plurality of spring fingers that may, if desired, be formed integrally with the piston 146.
  • Each of the spring fingers may include locking portions 154 thereof disposed for locking engagement within an annular groove 156 defined in the lower tubular section of the mandrel.
  • the spring fingers 152 will ordinarily be urged radially outwardly away from locking engage- 'ment within the annular groove 156, but may be cammed inwardly to establish such locking engagement by a plurality of cam elements 158 defined on the finger elements, which cam elements may engage an annular cam surface 160 defined by a reduced diameter portion 162 defined within the lower housing section 74.
  • Upward movement of the piston element 146, relative to the lower housing section 74 of the safety valve mechanism, may be limited by a tapered annular surface 164, also defined by the reduced diameter portion 162 of the housing, which may be engaged by an annular tapered surface 166 defined on the upper surface of the piston element.
  • Downward movement of the piston element relative to the moveable lower tubular section of the mandrel 96 may be limited by an annular enlargement 168 defined on the mandrel, which enlargement is engaged by the piston as the piston is urged downwardly by application of pressure upstream of the valving mechanism.
  • the unlocking movement of the spring fingers is caused partly by the inherent spring nature thereof and partly by outward forces on the fingers that are caused by interaction between an annular shoulder 170, defined by the locking groove 156 and tapered cam surfaces 155, defining the upper extremities of each of the spring fingers. If a condition of normal flow has resumed thorugh the orifice 140 at the time the piston 146 is released from the mandrel, a force developed by pressure differential across the flow bean will be of sufficient magnitude to overcome the compression of spring 98 and will thereby maintain the mandrel in its upper or normal flow position.
  • One suitable means for preventing reclosing of the valve mechanism, immediately following release of the piston 146 from the mandrel, may conveniently take the form of a restriction modifying pin 172 that may be provided with a threaded portion 174 adapted to be received within an internally threaded blind bore 176 defined in the retainer post element 134.
  • the pin 172 may be disposed centrally of the retainer post 134 and may be adapted to be received within the restricted orifice 140 of the choke bean 138 upon movement of the valve face element into closing engagement with the valve head 124.
  • the restricted orifice 140 of the choke bean is likewise maintained in accurate alignment with the pin 172 by an upper guide surface 178 defined by an internal annular flange 180 on the coupling element 64 and by an internal guide surface 182 defined by the piston 146.
  • the guide surfaces 178 and 182 effectively center the mandrel 86, relative to the housing 52 of the valve 20, and accurately guide the mandrel as it reciprocates within the valve housing responsive to pressure and flow conditions.
  • the compression spring 98 will tend to force the mandrel downwardly causing reclosure of the valve mechanism, because conditions of fluid flow across the choke bean 138 will not at this time have reached a sufficient velocity to develop a pressure differential across the choke of sufficient magnitude to develop a resultant force that is capable of stopping spring urged downward movement of the mandrel before it moves to its completely closed position.
  • the choke modifying pin 172 will enter the restricted orifice 140 of the choke bean, thereby restricting the flow of fluid through the orifice.
  • the pin 172 is of such size, relative to the orifice, that flow of fluid is allowed to continue through the orifice, but such flow will be substantially restricted, as compared with the unrestricted dimension of the orifice.
  • the restricted flow condition caused by insertion of the pin into the orifice logically develops a condition of extremely high differential pressure across the choke bean 138 and thereby develops a resultant force of large mangitude acting through the choke bean 138 on the mandrel structure 86.
  • the mandrel Before the face portion of the valve can reach a sealed and closed relationship with the head portion of the valve mechanism, the mandrel will be suddenly subjected to an upward force that stops the downward movement of the mandrel and thrusts it upwardly against the compression of the spring 98.
  • the choke bean 138 may be oscillated a few cycles by the mandrel relative to the choke restricting pin 172, with less rebounding of the mandrel during each succeeding cycle, responsive to a lower rate of accelleration of the mandrel as it starts moving downwardly under the force developed by the spring 98.
  • a normal flow condition will be de veloped across the choke bean which produces a pressure differential developing a resultant force of sufficient magnitude to compress the spring 98 and urge the mandrel upwardly to its normal operating position.
  • OPERATION Referring now to FIGS. 6, 7, 8 and 9 various operating conditions of the safety valve mechanism of this invention are depicted.
  • FIG. 6 the valve mechanism is illustrated in the normal operating position thereof, which is referred to as the disarmed-flowing" position. In this condition the valving mechanism is maintained in its open position and the valve opening piston is disconnected from the mandrel.
  • the valving mechanism is depicted in the closed position that it achieves, after having been closed by the compression spring 96, responsive to the development of a flow condition of insufficient velocity.
  • This position is referred to as the disarmedclosed position; the mechanism being disarmed because the valve opening piston is disconnected from the mandrel.
  • the safety valve mechanism of this invention is depicted in the armed-closed" position with the valving mechanism being maintained in the closed position thereof while the piston mechanism has moved downwardly into latched position with the mandrel, thereby substituting the surface area of the piston for the differential areas of the mandrel for subsequent pressure sensitive opening movement of the valve mechanism.
  • the safety valve mechanism is depicted in the armed-opening position with the valving mechanism in the open position thereof and the piston element disposed in latched or assembled relation with the mandrel.
  • the mandrel has not been moved to the uppermost position thereof by the piston and the reduced dismeter portion of the lower housing section maintains the spring fingers in latched engagement with the latching groove of the mandrel, causing the upper tapered cam surfaces of the locking portion 154 of spring fingers to engage the annular shoulders defined by the annular 156, thereby causing the mandrel to be urged upwardly.
  • the spring fingers 152 will be caused to move radially outwardly partly by the inherent spring nature of the fingers and partly by the outward force developed on the fingers by interaction between the annular shoulder 170 and the tapered cam surfaces 155 defining the upper extremities of the spring fingers, whereupon the spring fingers, and the piston 146 formed integrally therewith, will be released from connection with the mandrel.
  • valve chamber portion 142 of the housing For a more detailed description of the operational concepts of the present invention and with reference particularly to FIG. 6, where the valving mechanism is disposed in the disarmed-flowing condition, a condition of normal flow exists and fluid flowing from the production zone of the well will enter the valve chamber portion 142 of the housing through a plurality of flow passages 82 and 84. The production fluid then flows from the valve chamber and into the tubular conduit defined by the valve actuator assembly or mandrel 86, through the restricted orifice 140 in the choke bean 138.
  • the restriction to flow caused by the orifice 140 develops a pressure differential across the choke bean that induces a resultant force, acting upwardly on the choke bean and mandrel, that compresses the spring 98 and maintains the face portion 116 of the valving mechanism in the open position thereof relative to the stationary valve head portion 124.
  • the piston element, with its spring fingers and the mandrel, in this particular condition will be freely moveable elements that are completely disconnected from one another and will be moveable relative to one another.
  • the piston is pressure sensitive while the mandrel is velocity sensitive when the valve mechanism is in the disarmedflowing position.
  • the valving mechanism and the mandrel of the safety valve of this invention is depicted in the closed position thereof, but disarmed because the piston, and the spring fingers carried by the piston, are in disconnected relation with the mandrel.
  • the resultant force produced by the pressure differential across the choke bean 138 will become insufficient to overcome the pressure of the spring 98 and the spring will expand, thereby urging the mandrel downwardly and causing the face portion 116 of the valving mechanism to move into sealed relationship with the sealing element 128, carried by the stationary portion 124 of the valving mechanism, thereby completely interrupting the flow of fluid and ceasing production of the well.
  • the valve mechanism in the closed position, the valve mechanism becomes pressure sensitve and the area A1, subjected to formation pressure, being smaller than area A2, also subjected to formation pressure, will cause a resultant force to be induced tov the face portion 1 16 of the valve mechanism and to the mandrel, which resultant force causes the face portion and the mandrel to be urged toward the closed position thereof.
  • the valving mechanism in the disarmed and closed position thereof, as illustrated in FIG. 7, will be pressure sensitve and will be urged to the closed position by formation pressure. Regardless of how high formation pressure should become, the valve mechanism will not reopen, but, rather will be more tightly closed.
  • the piston element 146 In the disarmed and closed position, the piston element 146, also being pressure sensitive, will be urged upwardly bythe same pressure differential that exists across the valve mechanism, thereby causing it to engage and be restrained against further upward movement by the tapered stop surface 164. Again, as in FIG. 6, the spring fingers 152 will be disengaged from the annular locking groove 156, thereby allowing movement of either the mandrel or the piston independently of one another. Of course, in this particular position the mandrel will not be capable of upward movement responsive to formation pressure because of the net downward or closing force induced thereto by formation pressure acting upon the annular areas A1 and A2 as described above.
  • the valving mechanism of the safety valve is depicted in the armed and closed position thereof with the piston 14-6 interlocked with the mandrel 86, because of the locking portions 154 of the spring fingers 152 being urged, by interaction between the cam portion 158 of the spring fingers and the internal restricted portion 162 of the lower housing section, into latching engagement within the annular groove 156.
  • pressure may be injected into the tubing string above the valve mechanism to the extent that formation pressure is overcome.
  • the pressure sensitive piston 146 will be driven downwardly by the downward resultant force developed across the piston by the difference between the tubing pressure above the valve mechanism and formation pressure below the valve mechanism.
  • the cam portions 158 of the spring fingers 152 will engage the tapered cam surface 160 of the internal restricted portion 162 of the lower housing section 74 and will cause the spring fingers 152 to be urged radially inwardly.
  • the annular area of the piston 146 now interconnected with the mandrel by virtue of the latching engagement of the spring fingers 152 with the latching groove 156, becomes added to the mandrel.
  • the area of the piston provides a new resultant area which is the difference between the areas A3 and R and thereby causes the development of a net upward force acting upon the mandrel due to formation pressure. If pressure is balanced across the piston element 146, the mandrel will be subject only to the downward force produced by the compression spring 98 and tending to move the mandrel toward the closed position.
  • the pis ton element therefore modifiers the pressure sensitive nature of the valving mechanism when the piston is connected to the mandrel by the spring fingers 152.
  • the mandrel 86 will be subjected only to the downward force of the compression spring, which will be offset to some extent at this time by a condition of flow that is developing through the restricted orifice 140 of the choke bean 138 and which develops a resultant force, acting upwardly and opposing the force of the compression spring.
  • the resultant force acting upwardly through the choke bean on the mandrel will be insufficient to overcome the compression 98 because the spring, as the mandrel is released from its connection with piston 146, will compressed to its maximum extent.
  • the mandrel therefore will be accellerated downwardly at a very rapid rate and will tend to urge the face portion 116 of the valving mechanism into closed relation with the annular sealing element 128 carried by the stationary head portion 124.
  • the valving mechanism will not be allowed to fully close, however, because the pressure differential modifying pin 172 will enter the restricted orifice 140, thereby further restricting the orifice to the flow of fluid and greatly increasing the magnitude of differential pressure across the choke bean 138. This substantially increases the upward resultant force, acting upon the mandrel 82, which results in the mandrel being suddenly subjected to an upward thrust that drives the mandrel upwardly against the compression of the spring 98.
  • the mandrel If the condition of flow existing across the flow bean is insufficient at this time to fully overcome the compression of the spring 98, the mandrel, with the valve face portion 116 connected thereto, will be urged downwardly at a lower rate of accelleration toward its closed position, where the pin 172 will again enter the orifice 140 and develop a pressure differential across the choke bean that again thrusts the mandrel against the compression of spring 98.
  • the mandrel may oscillate a few cycles until a rate of flow is developed thorugh the orifice 140 that is of sufficient magnitude to develop a resultant force that overcomes the compression of the spring. When this occurs the mandrel will be urged by the resultant force to its fully open position as illustrated in FIG. 6.
  • the piston 146 after becoming released from the mandrel and being sensitive to pressure, will be moved upwardly by a resultant force developed by pressure drop across the choke bean 138 until it shoulders out against the annular stop surface 164 in the manner shown in FIG. 6. After the reopening procedure has been fully accomplished, the valve mechanism will disposed in the disarmed-flowing condition, illustrated in FIG. 6 and the piston 146 will be disposed in its disarmed condition, also illustrated in FIG. 6.
  • the safety valve mechanism of this invention will remain in the disarmed and flowing condition until such time as the velocity of fluid flowing through the restricted orifice 140 again decreases to an unacceptable minimum level which allows the force induced by the compression spring 98 to overcome the resultant force acting upon the flow bean 138 and cause downward movement of the mandrel to the disarmed and closed position, illustrated in FIG. 7, where it will remain until such time as a reopening procedure is instituted in the manner explained above.
  • valve mechanism that will serve effectively to stop the flow of production fluid through a well production system in the event the velocity of flow should fall below a predetermined minimum rate.
  • the valve mechanism of my invention after being closed, will not be opened even though well conditions may be resumed that would otherwise result in normal production flow. The valve mechanism will remain closed until such time as a specific reopening procedure is instituted to cause selective opening of the valve mechanism. This particular feature allows production personnel to be aware that a condition of undesirable flow rate has developed causing the well to shut in.
  • valve mechanism of my invention After the valve mechanism of my invention has become closed, responsive to conditions of abnormally low rate of flow, the valve mechanism is pressure sensitive, but is urged to closed position thereof by a resultant force produced by formation pressure acting upon differential areas of the valve actuating mechanism. Regardless how high pressure upstream of the valve mechanism may increase, the valve mechanism will always be subjected to a net downward resultant force tending to maintain the valve mechanism in the closed position thereof. Automatic resumption of production of the well will be effectively prevented after the valve mechanism has closed.
  • valve mechanism When it is desired to reopen the valve mechanism and again place the production system of the well on stream, I have provided a mechanism that effectively changes the pressure sensitive nature of the valve mechanism by modifying the areas that are subjected to differential pressure existing across the valve mechanism. After the pressure sensitive nature of the valve mechanism has been selectively modified, the valve mechanism may be selectively opened, responsive to formation pressure, and production through the tubing string, with which the safety valve mechanism is associated, may be resumed under conditions responsive solely to the velocity of fluid flowing through the valve mechanism.
  • Safety valves manufactured in accordance with the present invention are extremely safe and reliable and are capable of operating over extremely long periods of time without the development of any discernable wear.
  • a safety valve apparatus comprising:
  • an inner member movable between longintudinally spaced positions within an outer member, said members defining a flow passage; valve means for closing said flow passage in one position of said inner member, said flow passage being open in the other position of said inner member;
  • pressure sensitive means operable upon closure of said valve means and being responsive to upstream pressure for retaining said inner member in said one position; and second pressure sensitive means normally being disposed in inoperative relation to said pressure sensitive means and being selectively operable to combine with said pressure sensitive means and allow upstream pressure acting thereupon to develop a resultant force urging said inner member toward said other position.
  • said pressure sensitive means comprises surface areas surrounding said flow passage and subject to the difference in the pressures of fluids upstream and down stream of said valve means.
  • a safety valve apparatus as recited in claim 1, wherein said pressure sensitive means comprises:
  • hydraulically operable means responsive to a greater fluid pressure upstream of said valve means for overcoming said shifting means of said pressure sensitive means and for moving said inner member toward said other position to open said alve means.
  • piston means movable relatively along said inner member between an active position and an inactive position
  • said piston means having a transverse pressure area of larger size than said resultant surface subject to the difference in pressures of fluids upstream and downstream of said coengageable means, so that when said piston means is connected to said inner member an excess of upstream pressure over downstream pressure forces said piston means and said inner member toward said other position to disengage said coengageable means.
  • a safety valve apparatus as recited in claim 8, in-
  • a safety valve apparatus as recited in claim 5, in-
  • a safety valve apparatus as recited in claim 5, wherein:
  • said means for preventing return movement of said inner member to said one position comprises means for increasing pressure differential acting across said inner member sufficiently to develop a resultant force of sufficient magnitude to oppose said return movement.
  • a safety valve mechanism comprising:
  • valve elements being movable between an open position where fluid is allowed to flow and a closed position where the flow of fluid is blocked;
  • valve element flow responsive means for maintaining said valve elements in the open position thereof responsive to normal rate of flow through said valve mechanism
  • valve elements define first and second pressure responsive areas, said first pressure responsive area being greater than said second pressure responsive area and being responsive to upstream pressure to develop a resultant force urging said valve elements toward the closed position thereof.
  • a safety valve mechanism as recited in claim 12 wherein said means for selectively reversing the pressure responsive nature of said pressure responsive means comprises:
  • third pressure responsive area means being disposed in disconnected relation with said second pressure responsive means during conditions of normal operation and being selectively connectable to said second pressure responsive means whereby the conbined areas of said second and third pressure responsive area means is greater than the area defined by said first pressure responsive area means and upstream pressure acting upon said pressure responsive areas develops a resultant force urging said valve elements toward the open position thereof.
  • a safety valve mechanism as recited in claim 12 wherein said third pressure responsive area means comprises:
  • locking means for selectively locking said piston element to at least one of said valve elements.
  • said movable valve element having first and second pressure responsive areas defined thereon in the closed position of said valve elements and being responsive to upstream pressure for developing a resultant force acting upon said movable valve element and urging said movable valve element toward the closed position thereof;
  • said means for selectively reversing the pressure responsive nature of said pressure responsive means being third pressure responsive area means being normally disposed in inoperative relation to said first and second pressure responsive area means and being selectively operable to combine said third pressure responsive area means with said second pressure responsive area means and thereby cause upstream pressure acting upon said pressure responsive areas to develop a resultant force urging said movable valve element toward the open position thereof.
  • said means for selectively reversing the pressure responsive nature of said pressure responsive means being a pressure responsive piston element normally disposed in movable relation to said valve elements;
  • said piston element being movable by pressure downstream of said valve elements to a position causing locking actuation of said locking means.
  • one of said valve elements being stationary
  • valve actuator means being disposed for movement between open and closed positions thereof and defining flow passage means
  • valve actuator means restricting said flow passage means and being responsive to a predetermined rate of flow through said flow passage for maintaining said valve actuator means and said other valve element in the open positions thereof.
  • a valve mechanism comprising:
  • an actuator element being movably disposed within said housing and cooperating with said housing to define flow passage means through said valve mechanism
  • a first valve element being disposed in stationary relation with said housing
  • a second valve element being carried by said actuator element and beingvmovable to a closed position thereof by said actuator element for sealed relation with said first valve element to interrupt the flow of fluid through said flow passage means;
  • a valve mechanism as recited in claim 22 includes means for automatically increasing the restriction of said restriction means upon movement of said second valve element toward the closed position thereof and developing sufficient differential pressure across said restriction means to overcome said urging means and prevent reclosing movement of said second valve element.
  • said means for automatically modifying the restriction means carried by said valve mechanism and being operative to enter said restricted orifice and 25 further restrict the same.

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  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Geology (AREA)
  • Mining & Mineral Resources (AREA)
  • Physics & Mathematics (AREA)
  • Environmental & Geological Engineering (AREA)
  • Fluid Mechanics (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Safety Valves (AREA)
US00302545A 1972-10-31 1972-10-31 Low flow safety valve with pressure lock Expired - Lifetime US3848629A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
US00302545A US3848629A (en) 1972-10-31 1972-10-31 Low flow safety valve with pressure lock
CA184,292A CA991077A (en) 1972-10-31 1973-10-26 Low flow safety valve with pressure lock
GB5017273A GB1447993A (en) 1972-10-31 1973-10-29 Low flow safety valve apparatus
FR7338420A FR2204768B1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1972-10-31 1973-10-29
DE19732354275 DE2354275A1 (de) 1972-10-31 1973-10-30 Sicherheitsventileinrichtung

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Application Number Priority Date Filing Date Title
US00302545A US3848629A (en) 1972-10-31 1972-10-31 Low flow safety valve with pressure lock

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US3848629A true US3848629A (en) 1974-11-19

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US00302545A Expired - Lifetime US3848629A (en) 1972-10-31 1972-10-31 Low flow safety valve with pressure lock

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US (1) US3848629A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
CA (1) CA991077A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
DE (1) DE2354275A1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
FR (1) FR2204768B1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
GB (1) GB1447993A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4204513A (en) * 1978-11-15 1980-05-27 California Controls Company Hydraulic safety mechanism
US20090266555A1 (en) * 2008-04-23 2009-10-29 Schlumberger Technology Corporation System and method for controlling flow in a wellbore
WO2012094749A1 (en) * 2011-01-14 2012-07-19 Tesco Corporation Flow control diverter valve
CN103061707A (zh) * 2011-10-21 2013-04-24 中国石油天然气股份有限公司 井下循环开关阀
WO2015065196A1 (en) * 2013-10-30 2015-05-07 Wellbore As Downhole tool method and device
CN109734041A (zh) * 2019-01-11 2019-05-10 苏州三米格环保科技有限公司 加油枪及加油设备
CN112013140A (zh) * 2020-08-28 2020-12-01 胡中和 一种应用于空压机上的泄压阀

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Publication number Priority date Publication date Assignee Title
US4266614A (en) * 1979-07-12 1981-05-12 Otis Engineering Corporation Valve
US4721162A (en) * 1984-08-29 1988-01-26 Camco, Incorporated Fluid level controlled safety valve
US7740075B2 (en) 2008-07-09 2010-06-22 Schlumberger Technology Corporation Pressure relief actuated valves

Citations (4)

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Publication number Priority date Publication date Assignee Title
US3452777A (en) * 1964-08-24 1969-07-01 William W Dollison Pressure-responsive safety valve
US3477507A (en) * 1967-06-13 1969-11-11 Cook Testing Co Well safety valve
US3642070A (en) * 1970-05-06 1972-02-15 Otis Eng Co Safety valve system for gas light wells
US3724493A (en) * 1971-04-28 1973-04-03 Schlumberger Technology Corp Low flow safety valve

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3452777A (en) * 1964-08-24 1969-07-01 William W Dollison Pressure-responsive safety valve
US3477507A (en) * 1967-06-13 1969-11-11 Cook Testing Co Well safety valve
US3642070A (en) * 1970-05-06 1972-02-15 Otis Eng Co Safety valve system for gas light wells
US3724493A (en) * 1971-04-28 1973-04-03 Schlumberger Technology Corp Low flow safety valve

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4204513A (en) * 1978-11-15 1980-05-27 California Controls Company Hydraulic safety mechanism
US20090266555A1 (en) * 2008-04-23 2009-10-29 Schlumberger Technology Corporation System and method for controlling flow in a wellbore
US8002040B2 (en) 2008-04-23 2011-08-23 Schlumberger Technology Corporation System and method for controlling flow in a wellbore
US9507319B2 (en) 2011-01-14 2016-11-29 Schlumberger Technology Corporation Flow control diverter valve
WO2012094749A1 (en) * 2011-01-14 2012-07-19 Tesco Corporation Flow control diverter valve
US8733474B2 (en) 2011-01-14 2014-05-27 Schlumberger Technology Corporation Flow control diverter valve
CN103061707A (zh) * 2011-10-21 2013-04-24 中国石油天然气股份有限公司 井下循环开关阀
CN103061707B (zh) * 2011-10-21 2015-07-22 中国石油天然气股份有限公司 井下循环开关阀
WO2015065196A1 (en) * 2013-10-30 2015-05-07 Wellbore As Downhole tool method and device
US10392901B2 (en) 2013-10-30 2019-08-27 Ardyne Holdings Limited Downhole tool method and device
CN109734041A (zh) * 2019-01-11 2019-05-10 苏州三米格环保科技有限公司 加油枪及加油设备
CN109734041B (zh) * 2019-01-11 2024-06-11 苏州三米格科技有限公司 加油枪及加油设备
CN112013140A (zh) * 2020-08-28 2020-12-01 胡中和 一种应用于空压机上的泄压阀
CN112013140B (zh) * 2020-08-28 2022-04-29 大庆烯城炟石油技术开发有限公司 一种应用于空压机上的泄压阀

Also Published As

Publication number Publication date
FR2204768B1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1977-03-11
FR2204768A1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1974-05-24
GB1447993A (en) 1976-09-02
DE2354275A1 (de) 1974-05-09
CA991077A (en) 1976-06-15

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