????? ?? ???? ????? ????? ???? ??????? (TPR ????). ??? ?????? ????? ??????? ???? (???????? ???? ?? ?????) ??? ??? ???? ??????? ?? ????? ?? ???? ???? ?????? ??????. ??? ???????? ?? ???? ???. ???? ?????

???? ???. ??? ???? ?????? 30 ???? ???? ???? ?? ??? ??? ?????? ?? ???? ??? ??????? ???? ??????? ??????? ??? ?? ???? ???? ?? ??? ?? ???? ?????. ????? ?????? ?????? ??? ?? ????? ?????? ????? ????? ?????

A multi position safety valve retainable within an internal portion of a drill string casing and responsive to the greater differential pressure in an internal fluid passage to displace a valve head r

An improved safety valve includes piston-actuated provisions for gradually pressurizing a fluid-actuated motor during start-up of the system, preferably by way of a changeable flow restriction. In add

Lock-open mechanism for surface controlled subsurface safety valves. A lock-open sleeve can be positioned by wireline techniques to hold open the valve closure means for a subsurface safety valve. The

A new and improved subsurface safety valve which is inserted into well tubing without requiring removal of the tubing, and which replaces worn, deteriorated and fully or partially inoperative safety v

A safety valve for use with horizontal subsea trees as described which uses a two-part safety valve system. The first part containing a valve mechanism remains in the wellhead and is normally biased t

A safety valve for use in a wellbore formed in an earth formation, comprising a valve body having a fluid passage for passage of a stream of hydrocarbon fluid flowing from the earth formation via the