Crosswell seismic imaging of reservoir changes caused by CO<sub>2</sub>injection

Lazaratos, Spyros; Marion, Bruce P.

doi:10.1190/1.1437788

Cited by 76 publications

(31 citation statements)

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“…The large reductions are attributable to the CO 2 saturation and pore pressure increase in the McElroy field (Harris et al, 1995;Wang et al, 1998). The P-wave velocity decreases by an average of 5% (Figure 9b), which agrees with observations from previous studies (Lazaratos and Marion, 1997;Wang et al, 1998). In contrast, smoothconstrained inversion that overaverages velocity in the inversion domain might underestimate the velocity difference as a result of CO 2 injection (by an average of 3% in Figure 9a).…”

Section: Discussionsupporting

confidence: 89%

Applications of boundary-preserving seismic tomography for delineating reservoir boundaries and zones of CO2 saturation

Zhu

Harris

2015

GEOPHYSICS

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Delineating reservoir units is still a challenge for seismic approaches. Even high-resolution crosswell tomographic approaches that produce smooth velocity models to match traveltime data usually provide limited information about the boundaries of subsurface targets. A recent development of seismic traveltime tomography incorporated with a boundary-preserving regularization constraint promisingly helps to resolve ambiguities in reservoir boundaries, while allowing lateral variations. We applied a kind of boundarypreserving traveltime tomography to delineate boundaries of the reservoir and CO 2 -saturated zones. We chose the minimum gradient support as the regularization to preserve boundaries of the geologic target by penalizing smaller model gradients and smoothing small model variations caused by noise. We evaluated several synthetic and real data applications. Synthetic examples demonstrated that the boundary-preserving algorithm produced improved recovery of the profile shape and velocity values of the blocky targets. Two real applications were for delineating the top and base of the reservoir in the King Mountain field, and for delineating a CO 2 -saturated zone in the McElroy field. These inversion results suggested that the boundarypreserving inversion is able to provide better delineation of the top and base boundaries of the reservoir and boundaries of the CO 2 -saturated zone than the conventional smooth-constrained inversion.

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Section: Discussionsupporting

confidence: 89%

Applications of boundary-preserving seismic tomography for delineating reservoir boundaries and zones of CO2 saturation

Zhu

Harris

2015

GEOPHYSICS

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“…For example, carbon sequestration involves the injection of captured CO 2 into the subsurface. To ensure the proper containment of a CO 2 plume, time-lapse crosswell seismic can be used to map velocity changes in the reservoir (Lazaratos and Marion, 1997;Ajo-Franklin et al, 2013). A preinjection survey (baseline) is acquired and processed using the standard processing workflow.…”

Section: Data Processingmentioning

confidence: 99%

“…As a result, the frequency content of crosswell seismic data can reach frequencies greater than 1000 Hz (Lazaratos and Marion, 1997), bridging the gap between surface-seismic methods and sonic-log measurements ( Figure 1). Gorka Garcia Leiceaga 1 , Bruce Marion 1 , Katie Mahoney O'Sullivan 1 , George Bunge 1 , Jacob Thymann Nielsen 1 , and Andrew Fryer 1 Acquisition Use of crosswell seismic technology requires two nearby wells, one for the source and the other for placing the receiver tool string.…”

Section: Introductionmentioning

confidence: 98%

Crosswell seismic applications for improved reservoir understanding

et al. 2015

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Crosswell seismic (CS) technology provides a high-resolution image of the subsurface between two nearby wells. Crosswell seismic data can reach frequencies greater than 1000 Hz, which makes the technology applicable to many reservoir-development challenges in hydrocarbon exploration and production studies that require high resolution. Applications of crosswell seismic data range from structural and stratigraphic interpretation to reservoir monitoring and enhanced oil recovery (EOR). When integrated with rock physics, crosswell seismic data can be used in reservoir-characterization studies, which potentially could be used for enhancing the resolution of rock properties derived from 3D surface-seismic data to that of crosswell resolution. In addition, velocity models obtained from crosswell seismic data can be used to better predict event locations in microseismic data processing.

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“…Time-lapse seismic tomography is an important geophysical approach used to monitor the depletion of oil and gas reservoirs during production (Vesnaver et al, 2003;Ayeni and Biondi, 2010); to monitor the sequestration of CO 2 (e.g., Lazaratos and Marion, 1997;Ajo-Franklin et al, 2007a); and to monitor geothermal fields, active volcanoes, or remediation of contaminant plumes (e.g., McKenna et al, 2001). Several time-lapse seismictomography algorithms have been proposed in the literature, most of them based on traveltime tomography rather than on full-waveform inversion (e.g., Ayeni and Biondi, 2010).…”

Section: Introductionmentioning

confidence: 99%

2D time-lapse seismic tomography using an active time-constraint (ATC) approach

2015

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A 2D seismic time-lapse inversion approach can image the evolution of seismic velocities over time and space. The forward modeling is based on solving the eikonal equation using a second-order fast-marching method. Wave paths are represented by Fresnel volumes rather than by conventional rays. This approach accounts for complex velocity models and has the advantage of considering the effects of wave frequency on velocity resolution. The aim of time-lapse inversion is to find changes in velocities of each cell in the model as a function of time. Each model along the time axis is called a reference space model. This approach can be simplified into an inverse problem that seeks the optimum of several reference space models taken together, using the approximation that the change in seismic velocity varies linearly in time between two subsequent reference models. The method is demonstrated on a synthetic example that includes regularization in time in the cost function and reduces inversion artifacts associated with noise in the data by comparison with independent inversions at each time.

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Crosswell seismic imaging of reservoir changes caused by CO₂injection

Cited by 76 publications

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Applications of boundary-preserving seismic tomography for delineating reservoir boundaries and zones of CO2 saturation

Applications of boundary-preserving seismic tomography for delineating reservoir boundaries and zones of CO2 saturation

Crosswell seismic applications for improved reservoir understanding

2D time-lapse seismic tomography using an active time-constraint (ATC) approach

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Crosswell seismic imaging of reservoir changes caused by CO2injection

Cited by 76 publications

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Applications of boundary-preserving seismic tomography for delineating reservoir boundaries and zones of CO2 saturation

Applications of boundary-preserving seismic tomography for delineating reservoir boundaries and zones of CO2 saturation

Crosswell seismic applications for improved reservoir understanding

2D time-lapse seismic tomography using an active time-constraint (ATC) approach

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Crosswell seismic imaging of reservoir changes caused by CO₂injection