Patent ID: 8875782

Claim:
An oil field system comprising: a main body having a bore therethrough, the main body comprising a connection at one end of the bore for, in use, connecting the main body to an existing wellhead, tree, or other oil field equipment; a transverse cavity extending along an axis through the bore and comprising openings to the outside of the main body on opposite sides and along the axis; a plurality of flow control devices for insertion, at different times, into the cavity to selectively control fluid flow through the bore; wherein the plurality of flow control devices includes a gate valve comprising a single part slidable to close fluid flow through the main body bore and drilling BOP rams designed to seal during drilling operations; wherein the cavity is shaped so as to be sealable either by the gate valve or the drilling BOP rams to control fluid flow through the main body bore; and wherein the main body comprises recessed portions in a wall of the bore for receiving valve seats for engagement, in use, with the gate valve.