离散滑脱滞后时间法深井气窜速度计算

考虑气体滑脱对气窜速度的影响，从停泵/启泵两阶段中气体的流动特性入手，提出了离散滑脱滞后时间法气体上窜速度计算模型。在多相流气体滑脱速度计算中，提出了时间滑移网格的算法。以四川元坝某井为具体工程实例进行了计算，经现场验证，该模型可满足作业需求。结果表明，采用离散滑脱滞后时间法计算深井气窜速度是可行的；深井段气体处于超临界状态，超临界态气体滑脱现象不严重，对气窜速度影响不大，临近井口段气体滑脱较大；不考虑气体滑脱与考虑气体滑脱相比，气窜速度误差高达76.36%；随停泵时间延长、监测气体显示时间延长、油气层顶界位置上移，迟到时间减小，气窜速度均呈现减小趋势。

Application of Slip Lag Time in Discrete to the Calculation of Gas upward Velocity in Deep Well

Considering the gas slipping velocity, the flow characteristics at the stopping and starting pumps are studied, and the method of slipping lag time in discrete is proposed for calculating the speed of gas slip in deep wells. The time sliding mesh algorithm is proposed in a multiphase flow, which is used to solve for the gas slipping velocity, and the data are calculated using a cubic spline function. Corresponding calculations are performed, and a control software is designed. We applied this mathematical model to a well in Yuanba Sichuan, and obtained results that met operational requirements. The gas remains in a supercritical state in the deep well, and the gas slippage is not serious and has little effect on the gas upward velocity. When the state of the gas changes from a supercritical state into a gas near the wellhead, substantial gas slippage occurs. If the gas slippage is not considered, the error rate is up to 76.36%. It was observed that with an increase in the pump stopping time and gas monitoring time, as well as a decrease in lag time, and that of the reservoir top boundary, upward velocities of the gas tend to decrease.