Research On Integrity Testing Technology Of Multilayer String In Sidetrack Well

Casing window sidetracking drills a new wellbore at a certain depth of the casing of the old well and uses resources such as the original well casing and surface facilities to avoid repeated investment in drilling new wells and increase oil well production and crude oil recovery.rate.However,compared with ordinary wellbore structures,casing sidetrack wells are more prone to casing damage,channeling outside the pipe,sand production and other problems after long-term development,and it is more difficult to repair and control.Aiming at this problem,this paper proposes a method for detecting the integrity of casing fenestration side drilling based on transient electromagnetic(TEM)eccentric array.Based on the TEM eccentric detection model and the magnetic field distribution characteristics,this paper derives the TEM response of the single-layer and double-layer pipe string structure of the eccentric probe in the sidetrack well.Combining with the principle of TEM double-layer pipe string integrity detection,a double-layer pipe string damage detection model based on eccentric probes is simulated and analyzed by COMSOL MULTIPHYSICS software.On this basis,in view of the error of a single eccentric sensor,an eccentric array detection method which is spirally distributed in four quadrants along the well axis is proposed.This method utilizes the direction recognition characteristics of the eccentric probe to identify the well trajectory and window shape of the sidetracking sidetrack well,realizes the integrity detection of the casing of the suspension section and the windowed section,and effectively improves the detection of the sidetrack well Accuracy.In addition,in view of the characteristics of large actual logging data and error prone to occur in the sidetrack well,a MFC-based sidetrack well data processing software was designed,which can eliminate abnormal points,depth compensation,and connection of logging data.Automatic hoop recognition,error correction,and pipe string imaging functions.Finally,using the eccentric array downhole detection system,many field tests were carried out in Shengli Oilfield.The test results show that,compared with the traditional electromagnetic detection model in the middle,the method for detecting the integrity of the multi-layer string of casing fenestration sidetracks proposed in this paper can not only detect the integrity of the sidetrack,but also can clearly detect the integrity of the sidetrack through data processing software Identifying the trajectory of the sidetracking window and accurately detecting the size of the window provides an important basis for the formulation of sidetracking logging technology and sand control technology.