Research On Borehole Collision Probability Of Directional Wells In Changqing Large Well Cluster

Tight oil reservoirs are widely distributed in Ordos basin with great potential.Due to the low permeability,high development cost and difficult production of tight reservoir,industrial cluster well operation mode is widely used at home and abroad to further reduce the cost and facilitate the later fracturing operation.With the wide application of "large well cluster" drilling mode in tight oil development,it is urgent to consider the safe distance between wells.Aiming at the problem of well trajectory anti-collision,this paper reviews the literature at home and abroad,investigates the research status of well trajectory measurement tools and measurement principles,measurement calculation methods,uncertainty of well trajectory and anti-collision evaluation of well trajectory,analyzes the errors and their sources in the process of well trajectory measurement,and studies the iscwsa-mwd error model,and uses the iscwsa-mwd error model to calculate The computer programming and visualization of the error ellipsoid are realized.On this basis,the corresponding correction method is given for the error source which causes the uncertainty of well trajectory.Finally,by judging the distance between the ellipsoid of the trajectory error of two adjacent wells,the anti-collision evaluation is carried out,and the research of this paper is verified by the cluster drilling data of Changqing Well.The main work of this paper includes the following aspects:(1)This paper studies the working principle of magnetic MWD tool and the acquisition of measurement parameters in directional well trajectory measurement,such as well deviation angle,azimuth angle and well depth.This paper summarizes the calculation methods of well trajectory measurement,and briefly introduces the calculation method of minimum curvature method.(2)The error sources in well trajectory measurement are analyzed,and computer programming is carried out by using iscwsa-mwd error model,and the visualization of error ellipsoid is realized.(3)Aiming at the uncertainty of well trajectory caused by deviation angle,azimuth angle and well depth in the process of well trajectory measurement,the error correction of well trajectory measurement is studied.(4)Based on the measured data of large well cluster in Longdong area of Changqing,this paper analyzes the uncertainty error of well trajectory,the early warning analysis of well collision,and completes the anti-collision analysis of directional wells in Changqing large well cluster based on the error correction method of well trajectory measurement.In this paper,the uncertainty of well trajectory and its collision risk assessment of directional wells in Changqing large cluster are studied by combining theoretical research and field case calculation.According to the research,the measurement error of well trajectory is corrected,which has a guiding role in improving the accuracy of well trajectory and reducing the probability of well collision.