US3794112A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Surface controlled subsurface safety valve
Assignee: ExxonMobil Upstream Research Co
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Filing: 1972-10-02
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Granted: 1974-02-26
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Expires: 1992-10-02
Abstract
Abstract A surface controlled subsurface safety valve is positioned in a well production tubing and an adjustable choke is installed in the surface production tubing. The safety valve is operated by the absolute pressure of the production fluids in the well tubing. The adjustable choke is controlled by a timer which periodically cycles the choke to reduce the flow area available for production of well fluids for a predetermined short period of time. The reduction in flow area causes a corresponding build up of pressure in the surface tubing which is transmitted down the well tubing to the subsurface valve. Biasing means urges the valve to its closed position while tubing pressure urges the valve to its open positions. During normal well flowing conditions the force of the tubing pressure is less than the force of the biasing means and the valve, while remaining fully open is moved by the biasing means towards its closed position. Such movement is retarded by a dash pot arrangement in the valve. Means are provided in the valve to bypass the dash pot and cause rapid closure of the valve when the valve has reached a predetermined point towards its closed position. Under normal operations before the valve reaches the point of rapid closure the tubing pressure force at the valve is increased substantially over the force of the biasing means and the valve is moved rapidly to its initial open position. The increase in tubing pressure at the valve results from reducing the flow area by means of the adjustable choke in the surface tubing.
Inventors
- 👤 T Hill
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 09:56
CPC Classifications
E; E21; E21B; E21B34/00; E21B34/06; E21B34/10; E21B34/108
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
155 words
A subsurface safety valve for use in closing off flow of well fluids through well tubing comprising: a valve housing; a flow tube arranged in said valve housing and movable between a first position in which well fluids are prevented from flowing through said flow tube and a second position in which well fluids are permitted to flow through said flow tube; biasing means for urging said flow tube to its first position; means for retarding movement of said flow tube from its second towards its first position; and said flow tube including means permitting the absolute pressure of said well fluids to act on said flow tube to move said flow tube, said flow tube being moved towards its second position against the bias of said biasing means when said absolute pressure exceeds a predetermined amount, said absolute pressure exceeding said predetermined amount periodically during movement of said flow tube towards its first position.
Claim 2
Dependent Claim
155 words
A subsurface safety valve for use in closing off flow of well fluids through well tubing comprising: a valve housing; a flow tube arranged in said valve housing and movable between a first position in which well fluids are prevented from flowing through said flow tube and a second position in which well fluids are permitted to flow through said flow tube; biasing means for urging said flow tube to its first position; means for retarding movement of said flow tube from its second towards its first position; and said flow tube including means permitting the absolute pressure of said well fluids to act on said flow tube to move said flow tube, said flow tube being moved towards its second position against the bias of said biasing means when said absolute pressure exceeds a predetermined amount, said absolute pressure exceeding said predetermined amount periodically during movement of said flow tube towards its first position.
Claim 3
Dependent Claim
46 words
A subsurface safety valve as recited in claim 1 in which when said flow tube reaches a third position between said second position and said first position, in its travel from its second towards its first position, said flow tube is returned to its second position.
Claim 4
Dependent Claim
82 words
A subsurface safety valve as recited in claim 2 including first, second and third chambers formed between said flow tube and said valve housing, said biasing means being arranged in said first chamber, said means for retarding movement of said flow tube being located in said second chamber and said means permitting the absolute pressure of said well fluids to act on said flow tube including an opening in said flow tube fluidly communicating said well fluid pressure and said third chamber.
Claim 5
Dependent Claim
74 words
A subsurface safety valve as recited in claim 3 in which two spaced apart shoulders extend from said flow tube to engage the inner wall of said valve housing to form together with the inner wall of said valve housing said first, second and third chambers, said second chamber containing hydraulic fluid and orifice means for restricting movement of said hydraulic fluid as said flow tube moves from its second to its third position.
Claim 6
Dependent Claim
17 words
A subsurface safety valve as recited in claim 4 in which said biasing means includes a spring.
Claim 7
Dependent Claim
21 words
A subsurface safety valve as recited in claim 5 in which said biasing means includes a spring and gas under pressure.
Claim 8
Dependent Claim
100 words
A subsurface safety valve as recited in claim 6 in which said flow tube includes an additional opening adjacent one end thereof and sealing means also adjacent said one end adapted to seal with said housing, said additional openinG being sealed off within said housing by said sealing means engaging said housing to close off flow of well fluids through said flow tube when said flow tube is in its first position, said additional opening fluidly communicating said well fluids and the interior of said flow tube when said flow tube is in positions other than said first position thereof.
Claim 9
Dependent Claim
58 words
A subsurface safety valve as recited in claim 7 including means arranged in said second chamber to permit said flow tube to move rapidly towards its first position after it has reached its third position, and means in said second chamber permitting said flow tube to move rapidly towards its second position in response to well fluid pressure.
Claim 10
Dependent Claim
190 words
A subsurface safety valve system for use in closing off flow of well fluids through well tubing comprising: a valve housing; a flow tube arranged in said valve housing and movable between a first position in which well fluids are prevented from flowing through said flow tube and a second position in which well fluids are permitted to flow through said flow tube; biasing means for urging said flow tube to its first position; means for retarding movement of said flow tube from its second towards its first position; said flow tube including means permitting the absolute pressure of said well fluids to act on said flow tube to move said flow tube, said flow tube being moved towards its second position against the bias of said biasing means when said absolute pressure exceeds a predetermined amount, said absolute pressure exceeding said predetermined amount periodically during movement of said flow tube towards its first position; and a surface choke arranged in said surface tubing adapted to be periodically closed to reduce the flow of well fluids therethrough and thereby increasing absolute pressure of the well fluids at the subsurface valve.
Claim 11
Dependent Claim
190 words
A subsurface safety valve system for use in closing off flow of well fluids through well tubing comprising: a valve housing; a flow tube arranged in said valve housing and movable between a first position in which well fluids are prevented from flowing through said flow tube and a second position in which well fluids are permitted to flow through said flow tube; biasing means for urging said flow tube to its first position; means for retarding movement of said flow tube from its second towards its first position; said flow tube including means permitting the absolute pressure of said well fluids to act on said flow tube to move said flow tube, said flow tube being moved towards its second position against the bias of said biasing means when said absolute pressure exceeds a predetermined amount, said absolute pressure exceeding said predetermined amount periodically during movement of said flow tube towards its first position; and a surface choke arranged in said surface tubing adapted to be periodically closed to reduce the flow of well fluids therethrough and thereby increasing absolute pressure of the well fluids at the subsurface valve.
Claim 12
Dependent Claim
35 words
A subsurface safety valve system as recited in claim 9 in which when said flow tube reaches a third position between said second and first positions said flow tube is returned to its second position.
Claim 13
Dependent Claim
83 words
A subsurface safety valve system as recited in claim 10 including first, second and third chambers formed between said flow tube and said valve housing, said biasing means being arranged in said first chamber, said means for retarding movement of said flow tube being located in said second chamber, and said means permitting the absolute pressure of said well fluids to act on said flow tube including an opening in said flow tube fluidly communicating said well fluid pressure and said third chamber.
Claim 14
Dependent Claim
71 words
A subsurface safety valve system as recited in claim 11 including two spaced apart shoulders extending from the outer wall of said flow tube to the inner wall of said valve housing forming with the inner wall of said valve housing said first, second and third chambers, said second chamber containing hydraulic fluid and orifice means for restricting movement of said flow tube from said second to said third position thereof.
Claim 15
Dependent Claim
18 words
A subsurface safety valve system as recited in claim 12 in which said biasing means includes a spring.
Claim 16
Dependent Claim
21 words
A subsurface safety valve system as recited in claim 13 in which said biasing means includes a spring and pressurized gas.
Claim 17
Dependent Claim
101 words
A subsurface safety valve system as recited in claim 14 in which said flow tube includes an additional opening adjacent one end thereof and sealing means also adjacent said one end adapted to seal with said housing, said additional openings being sealed off within said housing by said sealing means engaging said housing to close off flow of well fluids through said flow tube when said flow tube is in its first position, said additional opening fluidly communicating said well fluids and the interior of said flow tube when said flow tube is in positions other than said first position thereof.
Claim 18
Dependent Claim
56 words
A subsurface safety valve system as recited in claim 15 including means arranged in said second chamber to permit said flow tube to move rapidlY towards its first position from its third position, and means in said second chamber permitting said flow tube to move rapidly towards its second position in response to well fuid pressure.
Claim 19
Dependent Claim
32 words
A subsurface safety valve system as recited in claim 16 including timer means connected to said surface choke for periodically choking said surface choke to increase absolute pressure within said well tubing.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-02-25 | 1977-08-27 | 1978-02-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-25 | 1981-08-27 | 1982-02-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-25 | 1985-08-27 | 1986-02-26 | $7700.00 | Window Closed / Lapsed |