Quantitative interpretation of time‐lapse seismic data at Farnsworth field unit: Rock physics modeling, and calibration of simulated time‐lapse velocity responses

Abstract

This study investigates the contribution of fluid saturation variation to the time-lapse velocity response by performing fluid substitution modeling. The methodology is exemplified by the time-lapse seismic monitoring of carbon dioxide at Farnsworth field unit (FWU). In order to evaluate the fluid distribution in a matured oil reservoir, the Southwest Regional Partnership (SWP) acquired multiple vertical seismic profile (VSP) surveys at different times during the CO 2 -water alternatinggas (WAG) injection period. In this work, we present a thorough methodology for computing the elastic response of the saturated rock for different fluid saturations using a site-specific petro-elastic model (PEM). The output from the PEM was combined with results from a fluid compositional model to compute the seismic velocities at times corresponding to each VSP survey. To produce a calibrated simulated response, the measured time-lapse seismic velocities were integrated into the numerical simulation model. The mismatches between the predicted and measured time-lapse velocities were minimized through an iterative calibration process using a trained artificial neural network proxy (ANN) coupled with a particle swarm optimizer (PSO). Our study indicates that the hybrid optimization workflow can effectively perform the history matching. With an accurate prediction of the hydrodynamic properties, the migration of CO 2 within the subsurface was modeled by predicting the spatial velocity distribution for a radius of 305 m around the injection well. The technology demonstrated and the expertise gained from this study can guide similar CO 2 -WAG projects.

Time‐lapse VSP integration and calibration of subsurface stress field utilizing machine learning approaches: A case study of the morrow B formation, FWU

“…The Southwest Regional Partnership on Carbon Sequestration (SWP) has conducted several studies on FWU in the context of CO 2 -EOR operations, as evidenced by the works of Rasmussen et al 43 , Acheampong 44 , Will et al 45 , Adu-Gyamfi et al 46 , Ampomah et al 47 and Acheampong et al 4,5 The SWP is a constituent member of a larger network of seven partnerships that are engaged in a nationwide endeavor to investigate the sequestration and permanent containment of carbon dioxide as a means of mitigating the effects of global warming. SWP studies are geared towards assuring CO 2 containment within the FWU storage compartment.…”

“…Ampomah et al 47 . and Acheampong et al 4,5 . The SWP is a constituent member of a larger network of seven partnerships that are engaged in a nationwide endeavor to investigate the sequestration and permanent containment of carbon dioxide as a means of mitigating the effects of global warming.…”

“…[1][2][3] CCUS technologies generally involve injecting captured CO 2 in subsurface formation. Geologic formation such as coal seams, saline aquifers, or depleted oil reservoirs serve as potential sites for harmful gases such as CO 2 , and H 2 S. [4][5][6][7] Embarking on CO 2 -EOR projects provides the advantages of recovering additional oil with the added benefit of CO 2 being sequestered. 8,9,10 The storage of CO 2 in underground formations could potentially result in harmful gases leaking into surface waters.…”

“…13,[19][20][21] Attributes such as the seismic wave travel times, velocities, amplitudes, and seismic reflectivity have been utilized to update reservoir flow properties and monitor the preferential fluid movement. 4,5,11,22 For instance, In Salah, a well-known CCUS project in Algeria has CO 2 stripped from produced natural gas and reinjected into the Krebka formations' aquifer leg. Calibrated a coupled hydro-mechanical model over 5 years by modifying the young's modulus with interferometric synthetic aperture radar (InSAR) datasets for uplift A case study of the morrow B formation, FWU over three horizontal CO 2 injector wells.…”

“…Several publications on the calibration of a coupled hydro‐mechanical model using attributes computed from a VSP dataset have been found 13,19–21 . Attributes such as the seismic wave travel times, velocities, amplitudes, and seismic reflectivity have been utilized to update reservoir flow properties and monitor the preferential fluid movement 4,5,11,22 . For instance, In Salah, a well‐known CCUS project in Algeria has CO 2 stripped from produced natural gas and reinjected into the Krebka formations’ aquifer leg.…”