Wellbore instability is one of the concerns in the field of drilling engineering.This phenomenon is affected by several factors such as azimuth,inclination angle,in-situ stress,mud weight,and rock strength parameters....Wellbore instability is one of the concerns in the field of drilling engineering.This phenomenon is affected by several factors such as azimuth,inclination angle,in-situ stress,mud weight,and rock strength parameters.Among these factors,azimuth,inclination angle,and mud weight are controllable.The objective of this paper is to introduce a new procedure based on elastoplastic theory in wellbore stability solution to determine the optimum well trajectory and global minimum mud pressure required(GMMPR).Genetic algorithm(GA) was applied as a main optimization engine that employs proportional feedback controller to obtain the minimum mud pressure required(MMPR).The feedback function repeatedly calculated and updated the error between the simulated and set point of normalized yielded zone area(NYZA).To reduce computation expenses,an artificial neural network(ANN) was used as a proxy(surrogate model) to approximate the behavior of the actual wellbore model.The methodology was applied to a directional well in southwestern Iranian oilfield.The results demonstrated that the error between the predicted GMMPR and practical safe mud pressure was 4%for elastoplastic method,and 22%for conventional elastic solution.展开更多
The CR superconducting magnet is a dipole of the FAIR project of GSI in Germany.The quench of the strand is simulated using FEM software ANSYS.From the simulation,the quench propagation can be visualized. Programming ...The CR superconducting magnet is a dipole of the FAIR project of GSI in Germany.The quench of the strand is simulated using FEM software ANSYS.From the simulation,the quench propagation can be visualized. Programming with APDL,the value of propagation velocity of normal zone is calculated.Also the voltage increasing over time of the strand is computed and pictured.Furthermore,the Minimum Propagation Zone(MPZ)is studied. At last,the relation between the current and the propagation velocity of normal zone,and the influence of initial temperature on quench propagation are studied.展开更多
文摘Wellbore instability is one of the concerns in the field of drilling engineering.This phenomenon is affected by several factors such as azimuth,inclination angle,in-situ stress,mud weight,and rock strength parameters.Among these factors,azimuth,inclination angle,and mud weight are controllable.The objective of this paper is to introduce a new procedure based on elastoplastic theory in wellbore stability solution to determine the optimum well trajectory and global minimum mud pressure required(GMMPR).Genetic algorithm(GA) was applied as a main optimization engine that employs proportional feedback controller to obtain the minimum mud pressure required(MMPR).The feedback function repeatedly calculated and updated the error between the simulated and set point of normalized yielded zone area(NYZA).To reduce computation expenses,an artificial neural network(ANN) was used as a proxy(surrogate model) to approximate the behavior of the actual wellbore model.The methodology was applied to a directional well in southwestern Iranian oilfield.The results demonstrated that the error between the predicted GMMPR and practical safe mud pressure was 4%for elastoplastic method,and 22%for conventional elastic solution.
文摘The CR superconducting magnet is a dipole of the FAIR project of GSI in Germany.The quench of the strand is simulated using FEM software ANSYS.From the simulation,the quench propagation can be visualized. Programming with APDL,the value of propagation velocity of normal zone is calculated.Also the voltage increasing over time of the strand is computed and pictured.Furthermore,the Minimum Propagation Zone(MPZ)is studied. At last,the relation between the current and the propagation velocity of normal zone,and the influence of initial temperature on quench propagation are studied.
