Time-lapse monitoring of CO₂ sequestration: A site investigation through integration of reservoir properties, seismic imaging, and borehole and surface gravity data

Abstract

We have developed a feasibility study on the application of time-lapse gravity as a monitoring tool for a proposed [Formula: see text] sequestration test site. The results are a component of a larger geotechnical suitability study to evaluate a specific field’s potential for [Formula: see text] storage and to evaluate viable techniques for effective monitoring there. The reservoir model for this study was constructed from detailed reservoir data available through separate reservoir characterization studies of the field. The gravity inversion used was a highly constrained binary approach that incorporated reservoir geometry from seismic data and the internal 3D distributions of density change predicted from the reservoir engineering database. Incorporating borehole data for joint surface/borehole monitoring further improved the potential of time-lapse gravity to define [Formula: see text] movement during sequestration. In this paper, we present a subset of the entire study. Our results indicate that the site likely has a favorable combination of geometry, depth, thickness, and predicted density change from [Formula: see text] movement to be effectively monitored with surface time-lapse gravity.

Continuous gravity observation with a superconducting gravimeter at the Tomakomai CCS demonstration site, Japan: applicability to ground‐based monitoring of offshore CO2 geological storage

“…After time‐lapse borehole measurements were proposed, their feasibility was assessed at the Cranfield site in the United States . Several simulation studies have assessed the availability of gravimetric techniques for monitoring CO 2 storage …”

Using surface and borehole time‐lapse gravity to monitor CO2 in saline aquifers: a numerical feasibility study

“…The gravity method, cheaper to implement, responds to changes in density and has been successfully used as a monitoring method for water floods in gas reservoirs . Site‐specific numerical studies show that time‐lapse gravity can be successfully used as a monitoring tool for CCS . In this case, carbon dioxide replaces saline water, resulting in a negative density change, and hence a negative gravity change.…”

“…Its amplitude is comparable to that of the errors associated to time‐lapse gravity surveys, typically 5 μgals . To overcome the issue of distance between the measurements and the plume, borehole time‐lapse measurements have been suggested and numerically studied, and the first results from actual measurements are promising and hint at the detection of density changes associated to CO 2 storage at SECARB Cranfield site …”

“…7,8 Site-specifi c numerical studies show that time-lapse gravity can be successfully used as a monitoring tool for CCS. [9][10][11] In this case, carbon dioxide replaces saline water, resulting in a negative density change, and hence a negative gravity change.…”

Time-lapse gravity surveying as a monitoring tool for CO 2 storage

“…In this 343 case, modelling with more appropriate porosities would be required. In the event that a 344 gravity survey conducted at the surface cannot provide sufficient resolution, then 345 measurements taken downhole can significantly improve the results, provided that suitable 346 boreholes are in place (Krahenbuhl et al, 2015). Offset 500m x 500m from crest Perforated interval 100m, top of reservoir 495 …”