COMPARATIVE ANALYSIS OF RESERVES DETERMINATION TECHNIQUES IN OVERPRESSURED GAS RESERVOIRS

📄 Project Abstract

Conventional methods used in determining initial gas-in-place and reserves for a dry gas reservoir entails the use of P/z vs cumulative production data. In a normally pressured gas reservoir, the only important production mechanism is the compressibility of the gas. Many reservoir engineering calculations take advantage of this fact to simplify analysis. However, in deep geopressured gas reservoirs, the compressibility of the gas is much smaller and does not totally dominate production performance. Using simplified approaches may lead to serious errors in these cases. In geopressured systems, the compressibility of the rock and water may be just as large as the gas. Excluding these sources of energy from performance calculations would result in very pessimistic predictions of production versus pressure. Some investigators have postulated that water will be released from shales as the reservoir compacts during depletion. This would result in an internal water drive similar to aquifer in...