Well Flow Control System

1. Technical Field

This invention pertains to wells and a system for controlling flow in a well flow conduit which utilizes a standing valve. Standing valves are frequently installed in well flow conduits to permit formation fluids to flow into the well flow conduit and upward through the conduit and standing valve to the surface. Standing valves protect well formations from contamination, especially low pressure formations, by preventing fluids in the flow conductor from flowing or being pumped down the flow conduit into the formation.

2. Information

Otis Engineering Corporation Products and Services Catalog (OEC 5516) shows, on page 245, a typical ball/cage standing valve, used in a retrievable only standing valve assembly, which has been installed in a foot valve in a well flow conduit.

A standing valve embodiment of a lock mandrel is disclosed in copending application for patent, Ser. No. 449,807, filed 13 Dec., 1989 for EXPENDABLE DEVICES FOR WELL LOCK SYSTEM. This lock mandrel is expendable only as it has a lower locking ring, which prevents retrieval and the upper locking ring is retained in expanded position by a retainer ring releasably positioned on the lock mandrel body.

U.S. Pat. No. 4,352,366 discloses a retrievable standing valve having a ball valve which is rotated to close by upward flow through a choke in the ball member. U.S. Pat. No. 4,352,366 is herein incorporated for reference.

This invention provides a flow control system useful to control flow through a well flow conduit. The system includes a landing nipple in the well conduit and a simplified less costly expendable standing valve installed in the landing nipple. The landing nipple has an internal landing shoulder, seal bore and profiled groove. The standing valve has a through flow passage and a check valve in the flow passage. The check valve permits upward flow and prevents downward flow through the passage and standing valve. The standing valve has a resilient piston unit which seals in the landing nipple bore and expands into the landing nipple groove when the standing valve is installed in the landing nipple. Substantial upward flow through the standing valve is required to develop upward forces sufficient to retract the resilient piston from the nipple groove and move the standing valve upwardly out of the landing nipple. The standing valve also has a retractible landing ring releasably positioned in expanded position which lands on the landing nipple shoulder to stop downward movement of the standing valve in the landing nipple. The standing valve may be retrieved back to surface or expended downwardly out of the landing nipple by applying weight on the standing valve or pumping down the conduit to release the standing valve ring to move to retracted position.

An object of this invention is to provide a system for controlling flow in a conduit which permits upward flow and prevents downward flow in the conduit.

An object of this invention is to provide a system for controlling flow in a conduit wherein a standing valve is installed in a landing nipple and the standing valve may later be retrieved or expended downwardly from the landing nipple.

Also an object of this invention is to provide a system for controlling flow in a conduit wherein the standing valve installed in the landing nipple requires substantial upward flow volume through to move the standing valve upward from the landing nipple.

FIG. 1 is a sectional drawing in elevation of the landing nipple used in the system of this invention.

FIG. 2 is a partially sectioned drawing in elevation of the standing valve useful in the invention system.

FIG. 3 is a partially sectioned drawing in elevation showing the standing valve installed in the landing nipple.

FIG. 4 is a partially cross sectioned drawing viewed along line 4--4 in FIG. 3.

FIG. 1 shows the landing nipple 10 of the system of this invention, which has upper and lower connections 10a and 10b for connection into a well flow conduit, an internal landing shoulder 10c, a seal bore 10d and a profiled groove 10e.

FIG. 2 shows the standing valve 11 of the invention system. Valve 11 has a fishing neck 14 which is connected to valve body 15. A check valve 12 is retained between the fishing neck shoulder 14a and body shoulder 15a. Groove 15b in the body shoulder houses a resilient seal 16 which seals between the seat and body.

Check valve 12 includes a cage 12a, a seat 12b and a valve ball 12c captured between the seat and cage, which is sealingly engageable with the seat. The cage has a number of through flow passages 12d (See also FIG. 4).

A ring expander 17 is mounted around body 15 below body shoulder 15c. A "C" shaped spring ring 18 is releasably positioned in expanded position on the ring expander by shearable pins or screws 19. The spring ring has a landing surface 18a and a camming surface 18b which is engageable with a camming surface 15d on the body.

A piston unit 20 having a resilient portion 20a, which has a cylindrical section 20b and plurality of lips 20c, is mounted around the body and is sealed to the body with a resilient seal 21. A guide 22 is threaded on body 15 to retain the piston unit around the body. Valve 11 has a flow passage 23 for upward flow through.

The well flow control system of this invention may be utilized in a well by connecting the landing nipple 10 in a well flow conduit at the desired level as the flow conduit is being lowered into the well. Valve 11 may be moved downwardly in the flow conduit by pumping, on reeled tubing or wireline for installation in the landing nipple. Piston lips 20c fold inwardly and slidably seal as valve 11 moves downwardly in the well conduit. As the diameter of resilient section 20b is greater than seal bore 10d, section 20b is compressed and slidably seals in seal bore 10d when Valve 11 is moved downwardly into the landing nipple. Downward movement of valve 11 into landing nipple 10 is stopped when ring landing surface 18a contacts nipple landing shoulder 10c. At that time, cylindrical section 20b is adjacent landing nipple profiled groove 10e and expands into the groove, as shown in FIG. 3.

Now, higher fluid pressure in the conduit above check valve ball 12c sealingly engages the ball on seat 12b and prevents downward flow through valve 11 and landing nipple 10. Conversely, higher pressure below valve ball 12c in flow passage 23 lifts the valve ball to permit upward flow through cage flow passages 12d and passage 23 in valve 11.

Upward frictional and impingement forces developed by upward flow in flow passage 23 will tend to push valve 11 upwardly out of landing nipple 10. Piston section 20b has expanded into nipple groove 10e and folded piston lips 20c are pressing outwardly in nipple bore 10d developing frictional forces retaining valve 11 in the landing nipple. A substantial upward flow volume is necessary to develop sufficient upward forces to overcome forces retaining the valve in the landing nipple and "flow" valve 10 upwardly from nipple 11.

Valve 11 may now be retrieved from landing nipple 10 back to surface or expended downwardly from the landing nipple. To expend, downward force is applied on valve 11 in the form of weight or pumping fluid down the well conduit, which causes check valve ball 12c to sealingly engage seat 12b. Ring landing surface 18a is supported by nipple shoulder 10c and increased weight or pressure will shear screws 19 and move valve 11 downward and out of the lower end of nipple 10. As ring supply 17 moves down through ring 18, the ring retracts around body 15 and surface 18b may contact surface 15d to retain ring 18 retracted.