Calibration of High-Resolution Reservoir Models Using Transient Pressure Data

Abstract

Abstract Integrating dynamic data into high resolution reservoir models is a crucial aspect of any optimal reservoir development and management strategy. In this regard, pressure data provides several advantages. First, pressure transient tests are easier and less expensive to carry out in the field. Second, pressure responses can be obtained early in the field life compared to watercut or tracer data. Finally, the pressure perturbations travel much faster compared to tracer or water front, resulting in quicker response in the field. This makes interference tests much more appealing compared to tracer tests which may require months to see a field response. However, the computation cost and localized nature of pressure sensitivities pose difficulties in history matching transient pressure data with a finite difference model. Also, pressure tests from multiple wells are difficult to analyze because of superposition of pressure responses. We propose a fast and robust approach to integrating transient pressure data using a trajectory-based approach that relies on a high frequency asymptotic solution of the diffusivity equation. The trajectory or ray-based methods are routinely used in seismic tomography. In this paper, we make a detailed comparison of streamlines and seismic rays and examine the applicability of streamline-based methods for transient pressure data inversion. Specifically, the high frequency asymptotic approach allows us to analytically compute the sensitivity of the pressure data with respect to reservoir properties such as porosity and permeability. This results in a very efficient approach for the integration of pressure data into geologic models. We apply our proposed method to transient pressure data from both single well test and multi-well interference tests. Our results demonstrate the advantage of performing interference tests compared to performing tracer tests in terms of identifying heterogeneities early in the field life. Finally, we apply this approach to data from a multiwell interference test in a Middle Eastern reservoir. Specifically, the pressure data obtained from permanent downhole gauges (PDG) in multiple wells are utilized to determine communications in the reservoir and to derive quantitative information about the permeability distribution in the reservoir for potential aid in the design and optimization of a miscible gas flood.