4D gravity modeling: Integrating seismic data with highly constrained gravity inversions for effective reservoir monitoring

Abstract

We demonstrate a robust workflow for time-lapse gravity modeling in reservoir sequestration/production monitoring applications. This systematic approach outlines a reliable methodology to understanding the value and limitations of 4D gravity at a particular site, for both pre-acquisition decision making, and as a guide for post-data acquisition interpretation. To demonstrate, we present a multifaceted feasibility study for monitoring CO2 injection into a reservoir at various injection times using 4D micro-gravity method. The simulations are performed for a currently active CO2-EOR site, the Louisiana Delhi Field in the United State. We construct an accurate representation of the field directly from current seismic data, followed by application of binary inversion technology adapted to the time-lapse gravity problem and tailored to the specific site. Finally, we illustrate a method of resolution analysis to demonstrate the decreased recoverability of fluid movement at the site in the presence of varying data noise.