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dc.contributor.authorZhang, Tao
dc.contributor.authorLi, Yiteng
dc.contributor.authorSun, Shuyu
dc.date.accessioned2021-03-01T12:34:17Z
dc.date.available2021-03-01T12:34:17Z
dc.date.issued2019-03-10
dc.date.submitted2019-02-12
dc.identifier.citationZhang, T., Li, Y., & Sun, S. (2019). Phase equilibrium calculations in shale gas reservoirs. Capillarity, 2(1), 8–16. doi:10.26804/capi.2019.01.02
dc.identifier.issn2652-3310
dc.identifier.doi10.26804/capi.2019.01.02
dc.identifier.urihttp://hdl.handle.net/10754/667781
dc.description.abstractCompositional multiphase flow in subsurface porous media is becoming increasingly attractive due to issues related with enhanced oil recovery, CO2 sequestration and the urgent need for development in unconventional oil/gas reservoirs. One key effort to construct the mathematical model governing the compositional flow is to determine the phase compositions of the fluid mixture, and then calculate other related physical properties. In this paper, recent progress on phase equilibrium calculations in unconventional reservoirs has been reviewed and concluded with authors’ own analysis, especially focusing on the special mechanisms involved. Phase equilibrium calculation is the main approach to investigate phase behaviors, which could be conducted using different variable specifications, such as the NPT flash and NVT flash. Recently, diffuse interface models, which have been proved to possess a high consistency with thermodynamic laws, have been introduced in the phase equilibrium calculation, incorporating the realistic equation of state (EOS), e.g. Peng-Robinson EOS. In the NVT flash, the Helmholtz free energy is minimized instead of the Gibbs free energy used in NPT flash, and this thermodynamic state function is decomposed into two terms using the convex-concave splitting technique. A semi-implicit numerical scheme is applied to the dynamic model, which ensures the thermodynamic stability and then preserves the fast convergence property. A positive definite coefficient matrix is designed to meet the Onsager reciprocal principle so as to keep the entropy increasing property in the presence of capillary pressure, which is required by the second law of thermodynamics. The robustness of the proposed algorithm is demonstrated by using two numerical examples, one of which has up to seven components. In the complex fluid mixture, special phenomena could be captured from the global minimum of tangent plane distance functions and the phase envelope. It can be found that the boundary between the single-phase and vapor-liquid two phase regions shifts in the presence of capillary pressure, and then the area of each region changes accordingly. Furthermore, the effect of the nanopore size distribution on the phase behavior has been analyzed and a multi-scale scheme is presented based on literature reviews. Fluid properties including swelling factor, criticality, bubble point and volumetrics have been investigated thoroughly by comparing with the bulk fluid flow in a free channel.
dc.description.sponsorshipThe authors thank for the support from the National Natural Science Foundation of China (No. 51874262) and the Research Funding from King Abdullah University of Science and Technology (KAUST) through the grants BAS/1/1351-01-01.
dc.publisherYandy Scientific Press
dc.relation.urlhttps://www.yandy-ager.com/index.php/cap/article/view/162
dc.rightsThis article is open access distributed under the terms and conditions of the Creative Commons Attribution (CC BY-NC-ND) license, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
dc.rights.urihttps://creativecommons.org/licenses/by-nc-nd/4.0/
dc.titlePhase equilibrium calculations in shale gas reservoirs
dc.typeArticle
dc.contributor.departmentComputational Transport Phenomena Lab
dc.contributor.departmentEarth Science and Engineering Program
dc.contributor.departmentPhysical Science and Engineering (PSE) Division
dc.identifier.journalCapillarity
dc.eprint.versionPublisher's Version/PDF
dc.identifier.volume2
dc.identifier.issue1
dc.identifier.pages8-16
kaust.personLi, Yiteng
kaust.personSun, Shuyu
kaust.grant.numberBAS/1/1351-01-01
dc.date.accepted2019-03-03
refterms.dateFOA2021-03-01T12:37:53Z


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This article is open access distributed under the terms and conditions of the Creative Commons Attribution (CC BY-NC-ND) license, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Except where otherwise noted, this item's license is described as This article is open access distributed under the terms and conditions of the Creative Commons Attribution (CC BY-NC-ND) license, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.