利用压裂施工停泵压力数据计算裂缝高度

Calculation of fracture height using pump-off pressure data in fracturing construction

大规模体积压裂已成为致密油气井及非常规油气井开采的重要工程技术,压裂效果评价以及压裂设计优化是开发与工程技术人员关注的重要内容。为满足压裂效果评价和压裂设计优化的需求,针对裂缝高度参数获取困难的问题,运用高压流体压缩性及渗流理论,将滤波、停泵压力反演及达西定律的缝面积分相结合,建立裂缝高度的解析表达式。该研究首次提出了裂缝高度的求解算法,并在我国一口多段压裂水平井中进行了应用。结果表明:(1)通过对压裂施工停泵压力数据进行分析计算,能够提供裂缝高度及SRV(大规模改造)区域渗透率、裂缝半长等参数;(2)裂缝高度受到压力降落幅值、SRV区域渗透率及裂缝半长的影响,压力降落幅值越大,裂缝高度越大;SRV(大规模改造)区域渗透率越大,裂缝高度越小;裂缝半长越长,裂缝高度越小;(3)通过实例分析给出了例井裂缝高度为30.62 m,并与微地震数据进行了对比,误差在可接受范围内。该研究对评价压裂效果、优化压裂设计以及压裂后产能分析提供了资料依据,有着重要的指导意义。

Large-scale volumetric fracturing has become an important engineering technology for tight and unconventional oil and gas well production.Fracturing effect evaluation and fracturing design optimization are important contents which developers and engineers pay attention to.In order to realize the fracturing effect evaluation of fractures and provide the fracture parameters,this article adopt the high pressure fluid compressibility and seepage theory combining the filtering,stop the pump pressure inversion and joint surface integral of Darcy’s law,then the analytical expression of the fracture height analysis is obtained with the data from a large volume fracturing of fracturing pump stop.It has been applied in a multi-stage fractured horizontal well in China.The results show that:(1)The fracture height,SRV permeability and fracture half-length can be provided by analyzing and calculating the pump stop pressure data during fracturing operation;(2)Fracture height is affected by pressure drop amplitude,permeability of SRV region and fracture half-length.The higher the pressure drop amplitude,the higher the fracture height;the greater the permeability of SRV area,the smaller the fracture height;the longer the fracture half length,the smaller the fracture height.(3)The fracture height of an example well is 30.62 m,which is compared with the microseismic data,and the error is within the acceptable range.This study provides data basis for evaluating fracturing effect,optimizing fracturing design and analyzing productivity after fracturing,and has important guiding significance.