Abstract:

By the pressurized sealed gold tube pyrolysis experiments, the fluid composition of Jurassic coal series from Minhe Basin at different maturity was obtained, the fluid density was calculated by PR state equation in software PVT-sim, and the impact of CO₂ from the evolution of coal on fluid density was discussed particularly. The result shows that the fluid density of coal generated hydrocarbon decreases with the increasing of maturity. At 10-50 MPa, 25-125 ℃ and EASY%Ro at 0.86%-2.52%, the density of liquid phase and the vapor phase was 0.51-0.85 g/cm3 and 0.05-0.85 g/cm3 respectively. Large quantity of CO₂ would generate during the evolution of the coal, which will impact the petroleum density directly. In this study, the density of liquid and vapor fluid both increases with the increasing of CO₂ content. The density was changed with the change of deviation factor and average molecular weight. At low maturity stage, with the increasing of CO₂ content, the density was increasing mainly because of the decreasing of deviation factor（Z）. At high maturity stage, with the increasing of CO₂ content, the density was increasing mainly because of the increasing of average molecular weight.

Key words: sedimentary environment , sandstone reservoir , Shahejie Formation , Jidong Oilfield