Pacific Section AAPG, SPE and SEPM Joint Technical Conference

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Improving Earth Models Using Passive Data Co-Acquired With Active Source Data: The Long Beach 3D Seismic Survey

Abstract

Traditionally, passive seismic has been used in the oil and gas industry for monitoring hydraulic fracturing and induced seismicity. Recent introduction of autonomous-type (nodal) seismic data recording systems with continuous-recording capability for conventional active-source seismic reflection exploration surveys provide a valuable by-product, if the data is preserved: a continuous passive seismic dataset from a dense seismic network over the survey area. This presentation describes the results of applying various techniques to passive data acquired using a nodal seismic recording system from a 22 square mile 3D seismic reflection survey acquired in early 2011 in Long Beach, California. This continuous passive data set was mined for information that adds value to the active source data, as well as other information that would benefit exploration and earthquake-related studies of the study area. Natural seismicity and ambient noise provide the signal used to extract p-wave and shear-wave velocities, anisotropy information and seismic imaging products. Types of analyses include time-lapse ground motion studies, micro-earthquake detection and location, surface wave interferometry, ambient noise correlation for reflection imaging, receiver functions, and teleseismic event amplitude analysis. Recent work using a near-surface velocity model generated by surface wave interferometry to correct for near-surface velocity variations in the active source imaging process will be presented. Our conclusion is that the data mining of passive seismic data can add value to active seismic data and better understanding of geology in and around the survey area.