Study On Anti-collision Method Of Cluster Wells Based On Survey Data

Cluster well engineering has become a common engineering mode for efficient development of complex oil and gas fields.However,both the development of new blocks and the infilling of old wellsite are facing the technical problems of cluster well anticollision.Therefore,anti-collision technology is one of the core technologies to ensure safe and efficient operation of cluster well engineering.Based on the ISCWSA-MWD well trajectory error model,the anti-collision calculation method based on the survey data is established by theoretical derivation and numerical simulation.Using MATLAB,the calculation program of wellbore trajectory measurement error based on ISCWSA-MWD error model is compiled.Compared with the standard example,the error of the calculation result is less than 5%,which verifies the correctness of the calculation.Meanwhile,the visualization method of error ellipsoid is improved.This error method is used to calculate and analyze the measurement error of the actual drilling trajectory of the Fuling shale gas cluster well and the sensitivity of 22 error sources in the ISCWSA-MWD error model.A new visualization method of adjacent wells collision risk based on error ellipsoid synthesis is proposed,and the influence of well diameter is taken into account in the calculation of error ellipsoid,thus improving the calculation accuracy of adjacent wells directional separation coefficient.The results of the example analysis show that the ellipsoidal synthesis method of the adjacent wells in the cluster well makes the judgment of the risk of adjacent wells more intuitive and convenient;the misalignment error(SAG,MX,MY)and the depth error(DREF,DST,DSF)have the greatest influence on the semi-spindle of the error ellipsoid,while the influence of the axial magnetic interference error AMID and the geomagnetic inclination error AZD on the semi-spindle of the error ellipsoid second.