Study On Location Prediction Of Adjacent Well Based On Premagnetization Of Adjacent Well Casing

The borehole collision between cluster wells and intensified adjustment wells is one of the most prominent problems encountered in drilling.Most of the existing anti-collision technologies have certain applicable conditions and limitations.Most active anti-collision schemes are cumbersome and time-consuming,while the error of passive anti-collision schemes is too large.Therefore,this paper proposes to establish a prediction study of adjacent well location based on pre-magnetization of adjacent well casing,pre-magnetize adjacent well casing on the ground,enhance its magne tic induction intensity and increase its passive anti-collision.Safety distance,and the research results also show that this makes the magnetic field distribution around the casing more obvious,and improves the accuracy of underground passive collision prevention.Based on the theory of calculating magnetic field intensity around infinite casing in geomagnetic field,the calculating method of residual magnetic field intensity around infinite casing after pre-magnetization is given.O n the basis of reasonable simplification,the calculating method of residual magnetic field intensity around single casing after premagnetization in geomagnetic field is obtained.Six sleeves of different steel grades and sizes were magnetized and pre-magnetized by flaw detec tor.Then the sleeves were placed in an open environment without magnetic interference.The magnetic field vectors at different positions of parallel and vertical measuring lines were measured.The errors of theoretical calculation and measured results were compared and analyzed.The results showed that the average errors of six sleeves were basically within 10%.This table shows that the average errors of six sleeves are within 10%.The calculation method of residual magnetic field intensity around a single casing is reasonable.The distribution law of magnetic field around the casing after pre-magnetization is described by experiment and theoretical model.The distribution law of magnetic field around the casing in its parallel plane and vertical plane is obtained.After pre-magnetization of the coil,the magnetic field distribution is uniform,highly symmetrical,and the attenuation rate decreases from fast to slow.On this basis,the method of determining the pseudo-analysis section and the adjacent well casing section influencing the pseudo-analysis of the magnetic field intensity of the section are proposed.Then the local coordinate system is established,and the objective optimization function is established.A method of predicting the location of adjacent wells based on the premagnetization of adjacent well casing is formed.Through this method,the distance and orientation of the magnetic anomaly section relative to adjacent wells can be predicted.Based on this method,four groups of surface experiments are used to simulate the position of drilling relative to adjacent wells.Through the optimization calculation of objective function,the predicted position of magnetic anomaly initial point is less than 0.3m in 3.5m,and the relative error is about 10%.This method will not affect the normal production of adjacent wells.It only needs to measure the magnetic field information of adjacent wells in the drilling process.It shows that this method is feasible in engineering,which has a certain practical significance for enriching the existing anti-collision means.