do not delimit the scope of the invention referring to fig1 an offshore oil and gas production platform having a wireline retrievable safety valve lowered into a tubing retrievable safety valve is schematically illustrated and generally designated 10 a semi submersible platform 12 is centered over a submerged oil and gas formation 14 located below sea floor 16 wellhead 18 is located on deck 20 of platform 12 well 22 extends through the sea 24 and penetrates the various earth strata including formation 14 to form wellbore 26 disposed within wellbore 26 is casing 28 disposed within casing 28 and extending from wellhead 18 is production tubing 30 a pair of seal assemblies 32 34 provide a seal between tubing 30 and casing 28 to prevent the flow of production fluids therebetween during production formation fluids enter wellbore 26 through perforations 36 in casing 28 and travel into tubing 30 to wellhead 18 coupled within tubing 30 is a tubing retrievable safety valve 38 as is well known in the art multiple tubing retrievable safety valves are commonly installed as part of tubing string 30 to shut in production from formation 14 in response to a variety of abnormal and potentially dangerous conditions for convenience of illustration however only tubing retrievable safety valve 38.