Control system and control method for deep sea double-layer pipe shaft bottom three-channel pressure

Abstract

The invention discloses a control system and control method for deep sea double-layer pipe shaft bottom three-channel pressure. The control system comprises a double-layer pipe, a casing pipe, a bit,a transformation joint, an outer sleeve, an axial-flow pump, a turbine motor, a liquid level monitoring sensor, a valve group control unit, a double-layer pipe reflux manifold, a well drilling liquidpump inlet manifold, a well drilling pump and a well drilling liquid circulation jar, wherein the transformation joint is connected to the lower end of the double-layer pipe; the outer sleeve is arranged at the upper half part of the axial-flow pump in a sleeving manner; the axial-flow pump and the outer sleeve are connected to the lower end and the middle part of the transformation joint; the axial-flow pump, the turbine motor and the bit are sequentially connected; the double-layer pipe is arranged in the casing pipe; and the inner pipe, the outer pipe and the casing pipe are concentric tubecolumns. According to the control system disclosed by the invention, three well drilling liquid channels are formed by the two-layer pipe; and lifting performance of the axial-flow pump is changed, so that self-adapting control of bottom hole pressure is realized, and dynamic balance of liquid column pressure of bottom hole well drilling liquid is effectively maintained.

Description

technical field [0001] The invention relates to a deep-sea double-tube well bottom three-channel pressure control system and a control method, belonging to the technical field of deep-water oil and gas drilling engineering. Background technique [0002] The exploitation of oil and gas resources is developing in the direction of deep formations, low permeability, offshore oil and gas, and unconventional oil and gas. my country is actively expanding the deep water field in the South China Sea. However, deep sea drilling and development are facing many difficulties, the most prominent one being the problem of "narrow drilling safety density window". , due to the loose sediments of the deep seabed and the seawater column, the range of formation pressure and fracture pressure is very narrow. Drilling accidents such as leakage, overflow, well collapse and stuck pipe will occur if the drilling safety density window is exceeded. How to stabilize the bottom hole pressure within the s...

AI Technical Summary

Problems solved by technology

However, the injection volume of low-density fluid is not easy to control, and it is easy to cause slug flow, which makes the drilling fluid density control accuracy poor

The injection point and injection device of low-density medium have complex structures, poor reliability, and high economic costs

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