Patent ID: 6267182
Filing Date: 2001-07-31
Classification: E21B

Abstract:
An apparatus for offshore oil production with primary gas separation and flow, by means of high pressure gas injection, comprising:a subsea primary separator receiving a production from an offshore oil well delivered from a wellhead through a flow line;a separated gas flow line connecting an upper part of said primary separator to a collecting vessel located at a gathering center;at least one flow line connecting a lower part of said subsea primary separator to a gathering center;a pressurized gas line which connects an annulus of the offshore well to a compressed gas supply system;at least one U-shaped pipe length, which is fitted with a shut-off valve, connecting said at least one flow line to said pressurized gas line;said pressurized gas line being fitted with a pressurized gas check valve near a point where said pressurized gas line connects to said wellhead so as to avoid back flow of gas originating from the annulus of said oil well; andwherein each said at least one flow line has a check valve located between said subsea primary separator and the point of connection to said at least one U-shaped pipe length in order to prevent the injected pressurized gas from exerting a back pressure which would adversely affect production from said oil producing well.