Advances in real-time simulation

Abstract

Subsurface modeling has provided numerous challenges to the reservoir characterization community over the years. As more data become available, it has become progressively more difficult to evaluate the interpretation results from each of the disparate disciplines represented. One of the most recent advances in data acquisition is the implementation of permanent downhole gauge (PDG) data, both for electronic flow meters and continuous-readout bottom-hole pressures. This kind of information provides real-time monitoring of the physical reservoir response to dynamic fluid-flow conditions resulting from production. The significant challenge for the geoscience team is to construct a geologic and numerical simulation model that can provide realistic answers consistent with the observed production and downhole gauge data. Westport Resources, an independent oil company, had a significant discovery in the South Timablier 316 block in the U.S. Gulf of Mexico. Three delineation wells provided confirmation of the hydrocarbon column, but did not encounter a fluid contact that was inferred from a pronounced flat spot in the seismic data. As is typical for many Gulf of Mexico shelf deposits, the turbiditic sand body had reached an updip stratigraphic pinchout near a salt-induced local high. Additional subsequent movement has left the reservoir portion of the deposit at a 45° slope. The reservoir is highly overpressured, with a pressure gradient on the order of 0.7 psi/ft, and the supercritical volatile oil is liquid at initial temperature and pressure. The dip of the reservoir provided a series of challenges during data processing, but the final poststack, time-migrated seismic data had sufficiently good vertical resolution to allow the delineation of both the top and base of the reservoir. Initial structural interpretation used autopicking techniques followed by detailed stratigraphic interpretations for each line throughout the reservoir volume and into the connected aquifer portion of the formation (Figure 1). Figure 1. The translucent structural …