微地震事件解释实例

微地震事件是储层对水力压裂的响应，其分布特征与压裂工艺、储层性质、区域构造应力等密切相关。因此，微地震事件解释须结合地质、油藏、工程等信息才能全面、准确地理解水力压裂裂缝延伸过程，提高压裂改造效果评价的可靠性及对储层和压裂工艺的认识，以指导井位部署和压裂设计。针对辽河探区Q1块和S268块三个微地震事件监测实例，利用微地震联合测井岩性分层、三维地震剖面以及三维地震数据相干体属性，探讨了影响微地震事件分布特征的因素，得到以下认识：1天然裂隙是影响微地震事件分布的重要地质因素，储层天然裂隙发育表现为微地震事件重叠，易于形成复杂的裂缝网络，储层天然裂隙不发育表现为微地震事件不重叠且集中分布，也可实现造长裂缝的目的，形成对称缝网；2对致密砂岩储层进行水力压裂时可将在全区稳定分布的煤层作为稳定隔挡层，控制缝高，提高改造效果；3进行井位部署时，要考虑邻近井的影响，采用合理的井间距和压裂工艺，最大限度地降低邻近井对压裂造成的影响；4地层变形形成的局部高应力区域可对水力压裂裂缝形成阻挡，影响改造效果，结合地震资料综合解释有助于微地震监测识别地层变形对压裂的影响。

Interpretation examples of microseismic events

Microseismic events are reservoir responses to hydraulic fracturing,and their distribution characteristics are closely related to fracturing technology,reservoir properties,local tectonic stress and so on.Therefore,the interpretation of microseismic events should be combined with multi-dicipline information such as geology,reservoirs,and engineering to fully and accurately understand the hydraulic fracturing process,improve the fracturing evaluation,and guide well location deployment and fracturing design.Based on three microseismic monitoring cases' interpretation combined with logging and 3D seismic data in the Block Q1 and Block S268 of Liaohe,we obtain the following understandings:①Natural fractures are important geological factors affecting the microseismic event distribution.Natural fractures in reservoirs are characterized by microseismic event overlap and complex fracture networks.Under-developed natural fractures do not cause microseismic event overlap,but create symmetrical-mesh long cracks; ②When hydraulic fracturing is performed on tight sandstone reservoirs,the stable coal seams in the entire area can be used as a stable barrier to control the height of fracturing cracks and improve the fracturing effect; ③When deploying well locations,the influence of adjacent wells should be considered,and reasonable well spacing and fracturing technology should be used to minimize the impact of adjacent wells; ④Locally high-stress zones formed by strata deformation can block hydraulic fracturing crack formation,and the joint microseismic,logging and seismic data interpretation helps identify strata deformation.