To counter the strength problem of drill string in well of large curvature and small diameter, well axis was taken as datum mis. Based on description of deflection of well an's and on analysis of three dimensional...To counter the strength problem of drill string in well of large curvature and small diameter, well axis was taken as datum mis. Based on description of deflection of well an's and on analysis of three dimensional forces of a small section of drill string, equilibrium differential equations of large deflection drill string were established. The internal forces were found by Longe-Kutta method. The stresses were found by using them and the strength prerequisite was established. Stresses of drill string in lateral horizontal well H767 were computed. The results are in agreement with those of finite element model and soft-rope rigidified model. But the method is simpler for computation than finite element model and is more perfect than soft-rope rigidified model. Curvature of the well is too large and there is stress concentration so that the fraction accident of drill string occurs.展开更多
The binary solid-liquid equilibrium of Dimethyl Terephthalate （DMT）, Dimethyl lsophthalate （DMI） and Dimeth- yl Phthalate （DMP） was investigated by experiment and differential scanning calorimetry （DSC）. The r...The binary solid-liquid equilibrium of Dimethyl Terephthalate （DMT）, Dimethyl lsophthalate （DMI） and Dimeth- yl Phthalate （DMP） was investigated by experiment and differential scanning calorimetry （DSC）. The result demonstrated DMT/DMI and DMT/DMP systems are eutectic while DMI/DMP is a solid-solution system. The eutectic temperature of DMT/DMI system is 336.7 K and that of DMT/DMP is 271.1 K. Furthermore, a classical solid-liquid phase equilibrium model was used to fit the experimental data of the eutectic systems of DMT/DMI and DMT/ DMP and the theoretical model could describe the eutectic solid-liquid phase diagrams properly.展开更多
A general deterministic time-inconsistent optimal control problem is formulated for ordinary differential equations. To find a time-consistent equilibrium value function and the corresponding time-consistent equilibri...A general deterministic time-inconsistent optimal control problem is formulated for ordinary differential equations. To find a time-consistent equilibrium value function and the corresponding time-consistent equilibrium control, a non-cooperative N-person differential game （but essentially cooperative in some sense） is introduced. Under certain conditions, it is proved that the open-loop Nash equilibrium value function of the N-person differential game converges to a time-consistent equilibrium value function of the original problem, which is the value function of a time-consistent optimal control problem. Moreover, it is proved that any optimal control of the time-consistent limit problem is a time-consistent equilibrium control of the original problem.展开更多
文摘To counter the strength problem of drill string in well of large curvature and small diameter, well axis was taken as datum mis. Based on description of deflection of well an's and on analysis of three dimensional forces of a small section of drill string, equilibrium differential equations of large deflection drill string were established. The internal forces were found by Longe-Kutta method. The stresses were found by using them and the strength prerequisite was established. Stresses of drill string in lateral horizontal well H767 were computed. The results are in agreement with those of finite element model and soft-rope rigidified model. But the method is simpler for computation than finite element model and is more perfect than soft-rope rigidified model. Curvature of the well is too large and there is stress concentration so that the fraction accident of drill string occurs.
文摘The binary solid-liquid equilibrium of Dimethyl Terephthalate （DMT）, Dimethyl lsophthalate （DMI） and Dimeth- yl Phthalate （DMP） was investigated by experiment and differential scanning calorimetry （DSC）. The result demonstrated DMT/DMI and DMT/DMP systems are eutectic while DMI/DMP is a solid-solution system. The eutectic temperature of DMT/DMI system is 336.7 K and that of DMT/DMP is 271.1 K. Furthermore, a classical solid-liquid phase equilibrium model was used to fit the experimental data of the eutectic systems of DMT/DMI and DMT/ DMP and the theoretical model could describe the eutectic solid-liquid phase diagrams properly.
文摘A general deterministic time-inconsistent optimal control problem is formulated for ordinary differential equations. To find a time-consistent equilibrium value function and the corresponding time-consistent equilibrium control, a non-cooperative N-person differential game （but essentially cooperative in some sense） is introduced. Under certain conditions, it is proved that the open-loop Nash equilibrium value function of the N-person differential game converges to a time-consistent equilibrium value function of the original problem, which is the value function of a time-consistent optimal control problem. Moreover, it is proved that any optimal control of the time-consistent limit problem is a time-consistent equilibrium control of the original problem.
