Development of the method for evaluation of subusurface fracture permeability by the multiplet-clustering analysis

开展了太阳表面裂缝渗透率评价方法的研究。我已经形成了评价渗透率的方法。在前人研究成果的基础上，提出了利用多元聚类分析确定的物源位置的时间推移分布来估计流体流动方向和渗透性裂缝系统发育过程的可能性。我还利用法国Soultz HDR油田的诱发声发射数据，通过构造应力场和裂缝方向的积分以及声发射源位置的时间推移分布，揭示了地热藏水力吞吐过程中裂缝的压力梯度和临界孔压可以估计出来。我还指出，很难估计压力的传播速度，因为事件的数量不足，而且震源并不分布在整个储集层。另一方面，笔者论证了通过细化地震矩释放增加率和震源面积增加率来评价储层中流体的流动程度。研究了地下裂缝的动态行为，探讨了识别相似微震(多重)的频带与多重震源位置所圈定的构造之间的关系，并在此基础上建立了基于多重聚类精确确定震源位置的地热储层裂缝渗透率评价方法，揭示了评价的制约因素。

I have carried out the research for the development of the method to evaluate the permeability of sunsurface fracture. I have taken form the method for the evaluation of permeability. On the basis of the results which obtained through the research before, I have shown that it is possible to estimate the direction of fluid flow and the growing process of permeable fracture system by the time lapse distribution of source location determined by the multiplet-clustering analysis. I have also revealed that the pressure gradient as well as the critical pore-pressure of fractures during the hydraulic stimulation of geothermal reservoir can be estimated by the integration of the tectonic stress field and the fracture orientation and the time lapse distribution of AE source location, where I used the induced AE data at the Soultz HDR field in France. I have also shown that it is difficult to estimate the velocity of pressure propagation because the number of events is insufficient number and the source does not distribute all over the reservoir. On the other hand, I have demonstrated that the degree of fluid flow in the reservoir can be evaluated by refining the increasing rate of seismic moment release and the increasing rate of source area. The dynamic behavior of subsurface fracture was also examined, where the relationship between the frequency band for identifying similar microearthquakes (multiplet) and the structures delineated by the source location of multiplet.As the results, I have developed the procedure to evaluate the fracture permeability in the geothermal reservoir on the basis of the precisely determined source location by the multiplet-clustering analysis, and also revealed the restriction on the evaluation.