页岩油藏开发合理焖井时间数值模拟

Numerical Simulation of Reasonable Soaking Time in Development of Shale Oil

为解决页岩油藏焖井开发过程中,合理焖井周期难以确定等问题,建立了包含油水渗吸置换的数学模型,基于全隐式方法构建了油水两相渗流、渗吸数值模拟模型。通过与实际井的生产数据进行对比验证模型的准确性。针对Y区块压裂水平井Y-1,分别计算了焖井0~160 d的累产油量。研究认为:随着焖井时间的增长,累产曲线的曲率变化逐渐平缓,压裂施工1000 d后对比得出最优焖井时间在40~80 d;焖井投资回报效果与生产时间呈正相关关系;针对合理焖井时间与影响因素众多的问题,计算了5口不同区块生产水平井的合理焖井时间,发现合理焖井时间与原油黏度呈现正相关关系,基质渗透率呈现负相关关系,与毛管力呈强正相关关系,为现场实际开发确定合理焖井时间提供一定指导意义。

In order to solve the problem that it is difficult to determine the reasonable soaking period in the development of shale reservoir,a mathematical model including oil-water imbibition displacement is established,and a numerical simulation model of oil-water two-phase seepage and imbibition is built based on the fully implicit method.The accuracy of the model is verified by comparing with the actual well production data.The cumulative oil production curves of fractured horizontal well Y-1 in Y block after shutting in well different days in the range of 0~160 d are obtained by calculation.It is shown that:With the increase of the soaking time,the change of the curvature of the cumulative production curve gradually decreases.By comparing the production data in 1000 days after fracturing,it is obtained that the optimal soaking time is 40~80 d;The return on investment of soaking is positively related to production time;As there are many factors affecting the reasonable soaking time,the reasonable soaking time of 5 horizontal wells in different blocks is calculated.It is found that the reasonable soaking time is positively related to crude oil viscosity,negatively correlated with matrix permeability,and strongly positively correlated with capillary force,which provides some guidance for determining the reasonable soaking time in the field development.