Interpretation examples of microseismic events

Abstract

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.