Permeability characterization of the Soultz and Ogachi large-scale reservoir using induced microseismicity
Permeability characterization of the Soultz and Ogachi large-scale reservoir using induced microseismicity
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DOI：
10.1190/1.1451573
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发表时间：
2002
期刊：
影响因子：
3.3
通讯作者：
P. Audigane;J. Royer;H. Kaieda
中科院分区：
文献类型：
--
作者：
P. Audigane;J. Royer;H. Kaieda
水力压裂是增加储层渗透性的常见方法。它包括将高压流体注入先导钻孔。这些水力测试引起局部地震发射（微震活动），假设孔隙压力进入周围受刺激岩石的扩散过程，可以从中得出大规模渗透率估计。这一程序适用于在 Soultz（法国）和 Ogachi（日本）两个地热站点附近收集的六个数据集。结果表明，该方法足以估计储层不同深度的大尺度渗透率张量。这种方法提供了与现场测量兼容的压裂前介质的渗透率。使用扩散方程的线源公式而不是经典的点源方法，提出了改进以计算在井段上进行注入的情况。该技术应用于连续的流体注入测试表明渗透率增加了一个数量级。在某些情况下观察到的低估是由于估计渗透率的规模不同（大约 1 km 3 对应于岩石的地震活动体积，而进行抽水或压力振荡测试时则对应于井周围几米）。该方法的优点之一是它提供了储层规模的渗透率张量估计。
Hydraulic fracturing is a common procedure to increase the permeability of a reservoir. It consists in injecting high-pressure fluid into pilot boreholes. These hydraulic tests induce locally seismic emission (microseismicity) from which large-scale permeability estimates can be derived assuming a diffusion-like process of the pore pressure into the surrounding stimulated rocks. Such a procedure is applied on six data sets collected in the vicinity of two geothermal sites at Soultz (France) and Ogachi (Japan). The results show that the method is adequate to estimate large-scale permeability tensors at different depths in the reservoir. Such an approach provides permeability of the medium before fracturing compatible with in situ measurements. Using a line source formulation of the diffusion equation rather than a classical point source approach, improvements are proposed for accounting in situation where the injection is performed on a well section. This technique applied to successive fluid-injection tests indicates an increase in permeability by an order of magnitude. The underestimates observed in some cases are attributed to the difference of scale at which the permeability is estimated (some 1 km 3 corresponding to the seismic active volume of rock compared to a few meters around the well for the pumping or pressure oscillation tests). One advantage of the proposed method is that it provides permeability tensor estimates at the reservoir scale.