BACK WELLHEAD VALVE OF OIL, OIL AND GAS WELL Russian patent published in 2009 - IPC E21B34/02 E21B33/03 

FIELD: oil and gas production.

SUBSTANCE: invention elates to gas-and-oil producing industry, particularly to devices for providing of undisturbed operation behavior of oil or oil and gas wells, described by annular show of gas. It includes hollow casing, outfitted by inlet branch of main component - formation fluid, mainly, oil, and inlet branch of throw down component, mainly, annular gas, and also outlet branch of mixture of main and throw down components. In casing of back pressure valve it is mounted inner block with casing in the form of sleeve with at least one opening, in its side wall for withdrawal of annular gas. External surface of side wall of sleeve is implemented with ability of its washing-off by formation fluid flow. Back pressure valve also includes installed in inner block sluice, containing system, formed not less than from two locking elements, each of which allows mobile and resting part. It provides undisturbed operation of well ensured by back pressure valve, implemented with ability of washing-off of sleeve of its inner block by warm formation fluid and guarantees outlet of throw down annular gas into flow of throw down in the same flow direction as formation fluid.

EFFECT: invention provides creation of optimal thermal conditions in area of back pressure valve at any conditions in area of wellhead, ensured by new industrial design of sluice, defining conditions of gas feeding into back pressure valve.

14 cl, 3 dwg