Velocity Modeling and Inversion Techniques for Locating Microseismic Events in Unconventional Reserv

• 作 者: Jianzhong Zhang Han Liu Zhihui Zou Zhonglai Huang
• 机 构: College of Marine Geosciences,Ocean University of China,Key Laboratory of Submarine Geosciences and
• 出 处: Journal of Earth Science
• 发表日期: 2015年04期
• 关键词: microseismic location velocity model building velocity error anisotropy unconven

A velocity model is an important factor influencing microseismic event locations.We review the velocity modeling and inversion techniques for locating microseismic events in exploration for unconventional oil and gas reservoirs.We first describe the geological and geophysical characteristics of reservoir formations related to hydraulic fracturing in heterogeneity,anisotropy,and variability,then discuss the influences of velocity estimation,anisotropy model,and their time-lapse changes on the accuracy in determining microseismic event locations,and then survey some typical methods for building velocity models in locating event locations.We conclude that the three tangled physical attributes of reservoirs make microseismic monitoring very challenging.The uncertainties in velocity model and ignoring its anisotropies and its variations in hydraulic fracturing can cause systematic mislocations of microseismic events which are unacceptable in microseismic monitoring.So,we propose some potential ways for building accurate velocity models.