Mechanical Analysis Of Stratified Water Injection Pipe String And Development Of Monitor

The stratified water injection string under the complicated conditions in the water injection development process,the force change of the string and the displacement of the packer,etc.,lead to the reduction of the life of the water injection string,which has become an urgent problem to be solved in oilfield water injection production.The current research has not been able to accurately determine the mechanical state of the water injection string with the packer under the constraints of the packer.The downhole string tester developed has a long experimental period and failed to obtain real-time sealing under different working conditions.Separator parameters.Therefore,mechanical analysis,packer displacement algorithm derivation,monitor development and experimental research are carried out on the water injection string.This dissertation mainly studies the complex stress state of the downhole layered water injection string,and conducts mechanical analysis of the layered water injection string,including the buckling deformation,axial deformation,axial load and strength safety analysis of the water injection string;the force method is used to untie the pipe.The statically indeterminate structure of the column packer.First,by establishing the three packer string mechanics model,derive the three packer string axial load calculation model,and then derive the three packer displacement algorithm,according to the three packer mechanics The model establishes a multi-packer string mechanical model,derives the four-packer string axial load calculation model,and derives the multi-packer displacement algorithm.The overall scheme design of the real-time monitoring device for the dynamic load of the pipe string was carried out,which mainly included the development scheme design of the downhole test sub,communication instrument,and surface controller.In order for the monitor to work normally after downhole and maximife the performance of the instrument,an experimental study on the test nipple and the communication instrument was carried out to ensure the normal operation of the monitor and supporting tools in the downhole.In addition,simulated well experiments were conducted to verify the correctness and feasibility of the monitor system design and provide data support for theoretical research.Through the above-mentioned study on the mechanics of the stratified water injection string,the deformation theory of the stratified water injection string is derived,the packer displacement algorithm is deduced,and a real-time monitor of casing string dynamic load is developed,and the well is simulated by the monitor.Experimental verification,the error analysis of the test value and the calculated value was carried out.The maximum data error between the test result and the calculation result of the 3# test subsection does not exceed 3.6%;the maximum data error between the test result and the calculation result of the 2# test subsection does not exceed 3.3%;1 #Test subsection The maximum error between the test results and the calculation results does not exceed3.6%.The error analysis of the theoretical calculation results based on the test results can be used to optimife the theoretical calculation model of the water injection pipe string mechanics,which is of great significance to the development of the later layered water injection pipe string.