华南古生界页岩储层压力预测方法及其应用研究

Pore pressure prediction of paleozoic shale reservoir in Southern China and its application

页岩储层压力是影响页岩气水平井部署和产能的重要因素,华南古生界页岩储层压力横向变化大,如何准确预测页岩储层压力变化对于页岩气勘探开发至关重要。实践证明常规油气地层压力预测方法不适用于华南古生界页岩气储层。针对Fillippone法与Eaton法在实际资料应用中存在的问题,考虑到在地层正常压实情况下Eaton和Fillippone的公式应满足压力关系以及速度关系,提出了新的地层压力预测方法,称为"Fillippone+Eaton"方法,建立了新的地层压力预测流程。该方法流程基于Fillippone公式的最大最小压实速度计算正常压实速度趋势,同时利用VSP资料进行测井速度标定,在速度谱和地震反射层位建立低频趋势的基础上,应用模型反演求取高精度的三维速度场.提出的方法在不同页岩气勘探区块进行了实际应用,预测结果与钻井实测资料吻合度高。

Reservoir pressure is an important factor that affects the deployment of shale gas horizontal wells and reservoir fracturing. The lateral change of pressure in southern China Paleozoic shale reservoir is large,so the ability to predict the pore pressure of target formation is critical for gas exploration. It is proved that the prediction methods for conventional reservoir do not apply to the southern China Paleozoic shale reservoir. Considering Fillippone method and Eaton method in the problems existing in the application of real data,and applying the pressures relationship and the velocities relationship under the normal compaction in Fillippone and Eaton＇s formulas,a new prediction method is put forward,called the ＂Fillippone ＋ Eaton ＂method,and a new prediction workflow is established. This workflow calculates the normal compaction velocity trend based on the maximum and minimum compaction velocities from the Fillippone formula,integrating with well logging velocity calibration using VSP data,and three-dimensional velocity model inversion using the low-frequency trend built by velocity spectrum and seismic reflectors. The presented workflow is applied in different shale gas exploration zones with the high match degrees between the predicted results and the drilling data.