3D Velocity Model Building Using Plane-wave Migration Velocity Analysis of Interpolated Seismic Data Acquired at the Farnsworth CO2-EOR Field

An accurate 3D velocity model is crucial for site characterization and analysis of time-lapse seismic data during geologic carbon utilization and storage. Wave-equation migration velocity analysis (WEMVA) with plane-wave common-image gathers is much more computationally efficient and requires much less computer memory storage than the conventional WEMVA in the shot domain. We develop an efficient method for 3D velocity model building using combined plane-wave common-image gathers along the inline and crossline directions. The field area where the seismic data was acquired is the Farnsworth Field Unit (FWU) in Texas, where the field operator is injecting anthropogenic CO₂ for enhanced oil recovery. Land access due to agricultural and oilfield activities limits placement of seismic sources and receivers in many surface regions. In the 3D Farnsworth seismic data, the source interval is 400 m in the inline direction and the receiver interval is 250 m in the crossline direction. These crossline and inline intervals are too large to form unaliased plane waves. To alleviate aliasing effects of missing seismic data and large source/receiver line intervals during plane-wave WEMVA, we employ a 3D compressive-sensing interpolation method to reconstruct the missing data and obtain dense seismic data along the inline and crossline directions. We verify our new method using 3D synthetic seismic data and demonstrate that our new method can produce a reliable migration velocity model using interpolated data. We apply our new method to 3D surface seismic data acquired at FWU, and obtain a 3D velocity model that can be used for high-resolution full-waveform inversion and reverse-time migration of time-lapse surface seismic data or time-lapse vertical seismic profiling data. Funding for this project is provided by the U.S. Department of Energy's (DOE) National Energy Technology Laboratory (NETL) through the Southwest Regional Partnership on Carbon Sequestration (SWP) under Award No. DE-FC26-05NT42591, and through contract DE-AC52-06NA25396 to Los Alamos National Laboratory.