Abstract: A check valve 200 has an elongate cylindrical tubular body 202 which provides mounting for a main flap valve 204. Mounted below the main valve 204 is a smaller multi-leaf flap valve 206. The smaller valve 206 is mounted on a housing 208 which is axially movable relative to the body 202. The housing 208 and valve 206 are normally biased upwardly and in this position a sleeve 214 formed on the upper end of the housing holds the main valve 204 open, and encloses the valve 204 within a valve recess 216 defined in the body 202. The sleeve 214 also extends across the main valve seat 218. Thus, during normal operation of the valve, with flow in a first direction, the sealing surfaces of the main valve 204 and the seat 218 are protected from the fluid by the sleeve 214.
Abstract: A locking mandrel is provided for use in downhole assembly and comprises a cylindrical body (12) having an annular series of openings (20) in which locking keys (21) are movably positioned, the keys (21) being biased radially inwardly, and an inner mandrel (13, 14) for moving the keys (21) from a withdrawn primed condition to an extended set position. Additionally the body (12) includes a series of movable no-go members (22) below the keys (21) which are extended in the primed condition so as to be engageable with a no-go ring (R2) on a downhole tubing string to axially arrest the body.
Abstract: An upstroke jar for use in downhole operations in an oil or gas well and for connection between a wireline and a tool comprises a casing defining an anvil and for connection to the tool, a hammer slidable axially within the casing for impacting with the anvil and for connection to the wireline, a hammer holder, a spring arrangement located between an abutment on the casing and an abutment on the hammer holder for compression on an operative movement of the hammer holder as a consequence of tension on the wireline and a connector releasable to free the hammer from the holder at the completion of the operative movement so that the freed hammer may impact with the anvil. The compression load on the spring present at the release is dependant on the extent of the operative movement from a rest position and the degree of compression of the spring means to obtain the operative movement. Adjustment of the release load present at the instant the hammer part is released by the connector is provided.
Abstract: The downhole lock assembly comprises a lock mandrel (10) connected to a running tool (11). The running tool holds an inner mandrel (13) located within the lock mandrel (10) in a position which allows lock-out keys (20) of the lock mandrel (10) to remain within the outside diameter of the lock mandrel body (12). Shear pins (34) are adapted on downward jarring against a landing nipple to expand the keys (20) and shear pins (33) are adapted on upward jarring to release the running tool. The running tool has a `tell-tale` collet (30), connected to it by a shear pin (32), to indicate that the lock mandrel is correctly set in the landing nipple, said collet being adapted when the running tool (11) is released from the lock mandrel (10) after setting the lock to disengage intact from the lock mandrel (10) if the lock-out keys (20) are correctly set and to foul the inner mandrel and shear the shear pin (32) if the lock-out keys are incorrectly set.