TRAPPED GAS SATURATIONS IN LEDUC-AGE RESERVOIRS

Gas production from Alberta's Leduc-age reservoirs, which originally c ontained more than 400 x 10(9)m(3) OGIP, has and will continue to be s ignificant. Estimating recoveries from these bottom-water drive pools has been difficult. Recoverable reserves are dependent upon both the t rapped gas saturation and aquifer performance. Generalizing core displ acement tests and applying limited field experience has been problemat ic. With a number of projects reaching maturity it is now possible to integrate core displacement data and field performance to clarify the factors that control gas recovery in these pools. This study is able t o demonstrate the dependence of trapped gas saturation on a number of factors including wettability, initial fluid saturation and permeabili ty. A simple analytical model was developed to estimate and interpret blowdown recoveries from these pools. The actual performance of a suit e of Leduc-age pools has been interpreted and applied to validate the model's applicability.