Abstract: A check valve comprising a body, a ball movable within a ball area of the body, a seat for receiving the ball, and a magnet for exerting a magnetic force on the ball is provided. The ball and seat are changeable between a closed state and an open state, the closed state having the ball in sealing engagement with the step, and the open state having a portion of the step separated from the ball with a space therebetween.

Abstract: A header with associated lubricator is for fluid handling at the wellhead of an oil and gas well where a plunger/lubricator lift system is deployed, and provides a novel compact lubricator with attached header which can replace a conventional wellhead flow-tee without modifying or moving other wellhead equipment to accommodate the new lubricator and header replacing the old flow-tee. A sub seal is provided at the header/lubricator attachment(s). The header with associated lubricator encloses a conduit with seals in the attachment interfaces between the header and lubricator or between the header and exit attachment means, where the conduit may also comprise a means of flow restriction through machined geometry or by retaining a reduced diameter or valve component through various means of attachment. The flow restrictor means may also be serviced via service access means provided in the header or lubricator exterior wall.

Abstract: A releasable connection for a downhole tool string is provided, having a first part with a connection profile and a second part with a releasable engagement profile that releasably engages the connection profile of the first part. The second part also has a locking piston, the locking piston moving axially along the second part between a locking position that locks the releasable engagement profile into engagement with the connection profile of the first part and a release position that permits the releasable engagement profile to release the connection profile of the second part, an expansion chamber in fluid communication with the locking piston, and a source of fluid pressure in communication with the expansion chamber, wherein, upon activation, the source of fluid pressure applies fluid pressure to move locking piston from the locking position toward the release position.