화학공학소재연구정보센터
Energy & Fuels, Vol.33, No.5, 3821-3827, 2019
A Study for Using CO2 To Enhance Natural Gas Recovery from Tight Reservoirs
A comprehensive study is presented on the interfacial behavior of all participating phases in a scenario of using carbon dioxide (CO2) to enhance the recovery of natural gas in tight sandstone reservoirs. Natural gas condensate is contacted with CO2 at an increasing pressure to determine the minimum miscibility pressure (MMP) by the vanishing interfacial tension method. Close to the MMP at a higher temperature, some compounds of the mixture are extracted, leaving a heavy oil fraction that remains immiscible. As the second reservoir liquid, formation water is extracted by CO2 from a tight sandstone sample and subsequently applied as a sessile drop for assessment of the wetting behavior inside the reservoir in the presence of injected CO2. The contact angle has been observed to increase with increasing CO2 pressure. It has been further observed that the water contact angle on a gas shale increased with increasing CO2 pressure more rapidly. The results suggest that CO2 could clear the gas flow path blocked by water and gas condensate. As a consequence, the recovery of natural gas would increase. This could also create greater potential for CO2 storage in gas-depleted reservoirs.