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
为缓解烤烟井窖式栽培中移栽期低温对烤烟产量和品质的影响,以主栽品种云烟97为材料,设置了T1(4月12日)、T2(4月19日)、T3(4月26日)3个不同移栽时间,调查不同移栽时间烤烟定植后成活率、植株生长情况、产量及品质。结果表明,T1、T2处理...为缓解烤烟井窖式栽培中移栽期低温对烤烟产量和品质的影响,以主栽品种云烟97为材料,设置了T1(4月12日)、T2(4月19日)、T3(4月26日)3个不同移栽时间,调查不同移栽时间烤烟定植后成活率、植株生长情况、产量及品质。结果表明,T1、T2处理杂草非常少,且二者总产量都超过1 700 kg·hm^(-2),T1上等烟量最高;3个处理植株长势都优于CK,其中T1植株长势最好,T2次之。T1处理还原糖、总糖、钾、氯、糖碱比最低,而总植物碱、总氮含量最高,钾氯比最高。T1处理中致香物质含量最高。因此,在道真县高海拔烟区提前7 d (4月12日)移栽能提高烤烟产量,提升烟叶品质。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.
文摘为缓解烤烟井窖式栽培中移栽期低温对烤烟产量和品质的影响,以主栽品种云烟97为材料,设置了T1(4月12日)、T2(4月19日)、T3(4月26日)3个不同移栽时间,调查不同移栽时间烤烟定植后成活率、植株生长情况、产量及品质。结果表明,T1、T2处理杂草非常少,且二者总产量都超过1 700 kg·hm^(-2),T1上等烟量最高;3个处理植株长势都优于CK,其中T1植株长势最好,T2次之。T1处理还原糖、总糖、钾、氯、糖碱比最低,而总植物碱、总氮含量最高,钾氯比最高。T1处理中致香物质含量最高。因此,在道真县高海拔烟区提前7 d (4月12日)移栽能提高烤烟产量,提升烟叶品质。
