Method and device for detecting gas cut position in drilling process

Abstract

The invention provides a method and a device for determining a gas cut position in the drilling process based on pressure wave time difference. The method comprises the following steps: enabling the device to take a pressure wave generated by the action of a hydraulic throttle valve as a wave source and judging whether the gas cut occurs or not by detecting the time difference between pressure waves received by a stand pipe pressure sensor and a sleeve pressure sensor; and according to the detected wellhead gas and liquid flow rate, the detected casing pressure and the detected transmission time difference between the pressure waves in an annulus and a drill rod, carrying out Runge-kutta iteration on all parameters by adopting an annulus hydraulic model, obtaining a corresponding relation existing among the distribution of void rates in different grids in the annulus, the wave velocity response time, the gas cut position and the pressure wave response time, determining an accurate position where the gas cut occurs. Compared with a traditional gas cut detection method, the method and the device provided by the invention have the beneficial effects that not only is the conventional gas cut detection function realized, but also the gas cut position can be accurately and quickly determined; and the method and the device have the advantages of accuracy in detection, strong real time, low equipment cost, simplicity in operation, wide application scope and the like.

Description

technical field [0001] The invention relates to a well logging method and a device, in particular to a method and a device for detecting gas intrusion positions during oil and natural gas drilling, and belongs to the field of well logging technology. Background technique [0002] During the drilling process, the excitatory pressure generated when drilling, the density of the drilling fluid is too low, and the abnormal formation pressure will cause the formation pressure to be greater than the annular pressure, causing the formation gas to invade the bottom of the well, and gas invasion occurs. In any working condition, when a gas kick occurs, there is a negative pressure difference between the annular space and the formation. If the gas kick is not detected in time and effective measures are not taken, as the gas migrates to the wellhead, it will cause The further increase of the negative pressure difference between the layers will intensify the gas invasion, further deterio...

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Problems solved by technology

[0004] However, the detection of gas invasion in the domestic and foreign drilling industry is limited to the judgment of gas invasion, and there is no method f...

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