Accurate calibration method for MWD (measurement while drilling) system and application of accurate calibration method

Abstract

The invention discloses an accurate calibration method for an MWD (measurement while drilling) system and the application of the accurate calibration method. The accurate calibration method comprises the step of calibrating a real-time calculation result of an attitude angle of the MWD system by virtue of an error model. According to the method, the attitude angle of the MWD system is calibrated by virtue of the error model under the condition that set values of a hole drift angle and an azimuth angle are unchanged, so that the fluctuation of calculation results of the hole drift angle and the azimuth angle can be effectively reduced, and a system error in an attitude angle calculation process can be eliminated; the hole drift angle and the azimuth angle are measured to guide the drilling of a drilling rig, so that accurate control over a well trajectory and improvement in the drilling accuracy can be effectively helped by the accurate calibration method. In addition, the accurate calibration method can also be popularized and applied to calibration flows of a series of products such as an automatic vertical drilling system and a rotary steering product.

Description

technical field [0001] The invention relates to a calibration method, in particular to an accurate calibration method of a MWD system and its application. Background technique [0002] The MWD (Measure While Dring) system can measure wellbore trajectory parameters in real time while drilling, including: inclination angle, azimuth angle, tool face angle and auxiliary parameters (such as temperature, etc.), and transmit the measurement results to the surface in real time during drilling In order to achieve the purpose of controlling the wellbore trajectory and improving the drilling precision, the measured wellbore trajectory parameters must have certain accuracy while satisfying real-time performance. The inclination angle refers to the angle between the tangent line of a certain point of the borehole and the vertical line, which reflects the degree of inclination of the drill bit, and the variation range is 0°~180°, that is, when the drilling tool is vertical The inclinatio...

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Problems solved by technology

[0004] The object of the present invention is to provide an accurate calibration method and application of a MWD system, which can effectively solve the problems in the prior art, especially when the setting values ​​of the well inclination and azimuth are constant, the well The calculation results of the oblique angle and azimuth still have large fluctuations, which cannot fundamentally achieve the problem of accurate calibration

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