Fremgangsmåte og apparat for brønnhodeomløp

A valve (136, 136′, 136″, 200) adapted to replace an existing valve of a wellhead (114). Valve (136, 136′, 136″, 200) can have similar dimensions as the existing valve it replaces to utilize existing wellhead connections. In one embodiment, a replacement bypass master valve (136) incorporates a fluid bypass pathway (168) to enable communication and conveyance of a production enhancing fluid (132) from a location external to the well through small diameter tubing (126) to a specific downhole location independent the position of a flow control member in interior chamber (166). Replacement bypass master valve (136′) can include anchor seal assembly (122′) disposed in locking profile 180 of upstream inlet bore (162) to enable communication from fluid bypass pathway (168) to lower injection conduit (128). In another embodiment, replacement valve (200) includes a groove in gate (208) sealingly receiving capillary injection tubing (204) when in a closed position.