In this paper, effects of water on shale recovery factor (RF) was investigated under different conditions experimentally. Some samples were saturated with oil at specific conditions. Other samples were partially saturated with water (NaCl), then saturated with oil. Then, number of cycles of N2 and CO2 injections were performed at fixed pressure, ambient temperature, and different operating conditions (e.g., soaking and production times). Results showed that as the number of cycles increased, RF also increased, and this increase depended on different parameters (e.g., soaking time). Results demonstrated increasing the soaking period results in higher RF. RFs of samples that were partially saturated with water were 17.34 % lower than RF of the base experiment by using N2 injection and 45.15 % lower by using CO2 injection. The RF achieved after conducting three cycles of CO2 injection was 36.33%, 6.14% higher than RF after performing five cycles of N2 injection. The results revealed that the efficacy of injecting CO2 to produce fluid from the core samples is higher than N2 at the same operating parameters. Results also demonstrated that presence of water has a negative impact on RF. Increasing flowback of drilling and fracturing fluids should be considered.
|State||Published - 2020|
|Event||54th U.S. Rock Mechanics/Geomechanics Symposium - Virtual, Online|
Duration: Jun 28 2020 → Jul 1 2020
|Conference||54th U.S. Rock Mechanics/Geomechanics Symposium|
|Period||06/28/20 → 07/1/20|