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Estimating Compaction Effects Using 4D Seismic, Mechanical Earth Models, and Pressure Transient Analysis
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 81st EAGE Conference and Exhibition 2019, Jun 2019, Volume 2019, p.1 - 5
Abstract
We present a demonstration of integrated 4D seismic interpretation, mechanical earth modelling, and Pressure Transient Analysis (PTA) to estimate changes in porosity and permeability around a producing well in a Gulf of Mexico oil field. The 4D seismic time shifts in the overburden are utilized to estimate the amount of dilation that the overburden shales exhibit. A mechanical earth model is employed to relate the changes in strain in the overburden to the changes in porosity in the reservoir. The PTA model around the well calculates the permeability near the borehole during depletion. The porositypermeability relationship, derived from core data and utilized in the reservoir model, enables an estimation of porosity change near the well that is supported by the 4D seismic and mechanical earth modelling. Furthermore, the pressure buildups suggest compaction in the well occurred suddenly, an observation that matches the plastic porosity loss forecasted by the mechanical earth model. The application is the first of its kind, demonstrating the use of different datatypes to derive consistent models to explain complex production effects, aiding to reduce uncertainty in the estimation of porosity and permeability changes and to provide guidance to ongoing production and reservoir management.