Annular pressure monitoring and controlling device for deepwater oil-gas well

Abstract

The invention relates to an annular pressure monitoring and controlling device for a wellhead of a deepwater oil-gas well. An upper piston in an upper hydraulic cylinder is connected with a lower piston in a lower hydraulic cylinder through a piston rod; the upper hydraulic cylinder is connected with the lower hydraulic cylinder through a connector; a pressure relief opening is formed in the side wall of the lower hydraulic cylinder; the bottom of the lower hydraulic cylinder is connected with a plurality of annular pressure tubes arranged on the periphery of a device mounting sleeve; an annular fluid inlet of the device mounting sleeve is provided with a pressure sensor; the output end of the pressure sensor is connected with a logic control system, the output end of the logic control system is connected with a hydraulic pump, and an oil outlet of the hydraulic pump is connected with an oil inlet of the upper hydraulic cylinder; when the device is used, the logic control system receives a pressure signal of the pressure sensor, and when the annular pressure signal is lower than a preset lower limit pressure value, the fluid is pressed into a sleeve annulus to be pressurized. The device has the advantages of preventing the situation that the annular air pressure is too low and accordingly oxygen is sucked in and the sleeve is corroded, and improving the air tightness.

Description

technical field [0001] The invention relates to an annular space pressure control device, in particular to an annular space pressure monitoring and control device for wellheads of deep water oil and gas wells. Background technique [0002] In the exploration and development of deep-water oil and gas resources, complex deep-sea geographical conditions and limited cementing technology make deep-water oil and gas wells form multiple closed annulus, which are filled with drilling fluid or completion fluid. During the production process, heat will be transferred to the fluid in the annular space, so the temperature effect will cause the fluid in the closed annular space to expand, resulting in the phenomenon of pressure in the annular space, which seriously threatens the safety of the pipe string and the integrity of the wellbore. [0003] A lot of research has been done on deepwater oil and gas well annular pressure control technology at home and abroad. These methods are all af...

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Problems solved by technology

[0002] In the exploration and development of deep-water oil and gas resources, complex deep-sea geographical conditions and limited cementing technology make deep-water oil and gas wells form multiple closed annulus, which are filled with drilling fluid or completion fluid. During the production process, heat will be transferred to the fluid in the annular space, so the temperature effect will cause the fluid in the closed annular space to expand, resulting in the phenomenon of pressure in the annular space, which seriously threatens the safety of the pipe string and the integrity of the wellbore

[0003] A lot of research has been done on deepwater oil and gas well annular pressure control technology at home and abroad. These methods are all affected by the deep water oil and gas well environment or wellbore structure, and the control effect on annular pressure is not very ideal.

Due to the particularity of the subsea casing head device, these control technologies can only perform pressure relief and supplementary control on a single annular pressure, and cannot monitor and control multi-annular pressure; existing control technologies cannot meet the operating requirements of API RP 90 Test the tightness and integrity of the casing annulus of deepwater oil and gas wells; during large-volume injection operations, the temperature of the liquid in the annulus decreases, causing its volume to shrink, which in turn causes the pressure of the annulus to drop, resulting in a vacuum in the annulus, which in turn inhales oxygen, causing corrosion

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