涪陵焦石坝页岩气层压力预测技术研究

压力系数是页岩气保存条件的综合判别指标。以涪陵焦石坝页岩气藏为例,基于压力偏低系数与高角度裂缝密度呈正相关关系,提出了复杂构造区基于裂缝修正的压力系数预测技术及实现流程。首先利用已知井建立封存型和逸散型压力系数预测模型,然后基于归一化的曲率属性定量表征裂缝密度,建立压力偏低系数预测模型,最后综合考虑地层速度和裂缝密度,实现复杂构造区的压力系数预测。焦石坝三维工区五峰组—龙马溪组页岩气层压力系数的预测结果表明,该技术适应性强,预测精度高,在中国南方多期构造运动影响下的勘探区块具有很好的推广应用价值。

Pressure coefficient is a comprehensive index for assessing preservation conditions of shale gas.Taking the Fuling Shale Gasfield as example,we proposed a complex structure adaptive method for predicting pressure coefficient based on fracture modification,and its implementing process,as a positive correlation between the lower pressure coefficient and the density of high-angle fractures is discovered.First,according to drilling results,two types of predicting models for pressure coefficient,a sealed type and a dissipation type,are established.Then,a predicting model for lower pressure coefficient is built up by quantitatively characterizing the fracture density using normalized curvature attribute.Finally,overall considering the formation velocity and the fracture density,the prediction for pressure coefficient in complex structure areas is realized.The application result of the Wufeng-Longmaxi shale gas reservoirs,in the Jiaoshiba block verified that this technique has strong adaptability and high prediction accuracy.

国家科技重大专项(2017ZX05036)和中国石油化工股份有限公司科技部基础研究项目(P15074)联合资助。