Seismic characterization and monitoring of a deep CO2 storage reservoir with 3D VSP using direct shear waves

We show a low-cost option for shear wave imaging of CO2 storage reservoirs that utilizes seismic waves that have been ignored by reflection seismologists for decades. These overlooked waves are direct-S waves generated by vertical-displacement vibrators and explosive sources. Shear waves... Full description

Saved in:
Bibliographic Details
Online Access: Get full text
doi: 10.1016/j.petrol.2016.04.019
Authors:Klokov, A.; Hardage, B.
Volume Title:Energy frontier research centers for investigating carbon sequestration
Volume Authors:Balhoff, M.T., editor
Source:Energy frontier research centers for investigating carbon sequestration, edited by M.T. Balhoff. Journal of Petroleum Science & Engineering, Vol.155, p.109-119. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0920-4105
Publication Date:2017
Note:In English. Based on Publisher-supplied data
Subjects:Body waves; Carbon dioxide; Carbon sequestration; Elastic waves; Faults; Geophones; Geophysical methods; Geophysical profiles; Geophysical surveys; Imagery; Monitoring; P-waves; Reservoir rocks; S-waves; Seismic methods; Seismic profiles; Seismic waves; Seismograms; SH-waves; Surveys; SV-waves; Synthetic seismograms; Three-dimensional models; Vertical seismic profiles; Illinois Basin-Decatur Project
Record ID:2020024184
Copyright Information:GeoRef, Copyright 2020 American Geosciences Institute.
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
We show a low-cost option for shear wave imaging of CO2 storage reservoirs that utilizes seismic waves that have been ignored by reflection seismologists for decades. These overlooked waves are direct-S waves generated by vertical-displacement vibrators and explosive sources. Shear waves are known to be helpful for detecting fractures and subtle faults which is critical for evaluating of CO2 storage capacity and sealing properties of the caprock. Utilizing direct-S waves produced by P-wave sources provides these benefits with no need to deploy special shear-wave sources. In addition, the SV-P mode, which is the upgoing P-wave produced by SV-to-P conversion, makes it possible to utilize S-wave attributes with data recorded by vertical geophones only. We developed a processing workflow to extract SV-SV and SV-P seismic modes from 3D VSP data acquired over a CO2 storage reservoir at Decatur, Illinois and tested these modes for seismic imaging and monitoring of the reservoir. In addition, we inspected an SH-SH mode that appeared interpretable in our data. We observed that direct-S images were consistent with traditional VSP direct-P images and calibration synthetic seismograms. A joint analysis of all available seismic modes allowed a constrained interpretation of faults within the reservoir. Direct-S waves appeared to not be advantageous for CO2 plume growth monitoring in the Decatur project. The SV-P mode demonstrated low sensitivity to CO2 concentration. The time-lapse difference for the SV-SV mode was uninterpretable due to the low signal-to-noise ratio of that mode.