Gas recovery factor from water drive gas reservoirs is very low compared to recovery made from depletion drive gas reservoirs. Other problems associated with gas recovery from water drive mechanism include high residual gas saturation in the water invaded zone of the reservoir, high volume of produced water, abandonment at high reservoir pressures and high possibility of hydrate formation in pipe lines. The use of carbon dioxide (CO 2 ) in displacing natural gas from volumetric gas reservoirs has been studied, practised and is successful. In this paper, it is proposed that extending this practice to gas reservoirs under strong water drive mechanism can improve recovery and control water influx.CO 2 is denser than natural gas and water is denser than CO 2 . The different densities of these fluids can be taken advantage of to boost natural gas recovery from water drive gas reservoirs. The continuous CO 2 injection process at the gas water (g/w) contact can partially prevent water encroachment into the system. The technique can change the water drive mechanism to full or partial depletion drive where CO 2 will separate the natural gas zone from direct contact with the water zone. Any eventual water invasion into the reservoir affects the CO 2 zone, not the upward moving natural gas zone. This technique was studied by simulation using data from a lean gas reservoir under strong water drive. Two cases were considered. In the first case, which is the reference case, gas production under water drive was allowed for 30years. In the second case, CO 2 was injected at the initial gas water contact for the same number of years. Simulation results showed that water production from the reservoir was drastically reduced to about 60% in the second case because the rate of water influx into the reservoir was controlled. Gas recovery from two producer wells out of three that were considered improved above 10% and gas condensate recovery was improved to about 4% over the period of production that CO 2 was injected.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.