On the development of a relative permeability equation of state

P. Purswani, M. S. Tawfik, Z. T. Karpyn, R. T. Johns

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Scopus citations

Abstract

Standard compositional simulators use composition-dependent cubic equations-of-state (EoS), but saturation-dependent relative permeability (kr). This discrepancy causes discontinuities, increasing computational time and reduced accuracy. To rectify this problem, kr has been recently defined as a state function, so that it becomes compositional dependent. Such a form of the kr EoS can significantly improve the convergence in compositional simulation, in that time step sizes are near the IMPEC stability limit and flash calculation convergence is improved. This paper revisits the development of kr EoS by defining relevant state variables and deriving functional forms of the state function via a methodical approach. The state variables include phase saturation, phase connectivity, wettability, capillary number, and pore topology. The developed EoS is constrained to physical boundary conditions. The model coefficients are estimated through linear regression on data collected from a pore-scale simulation study that estimates kr based on micro-CT image analysis. The results show that a simple quadratic expression gives an excellent match with simulation measurements from the literature. The goodness of fit (R2) value is 0.97 for kr at variable phase saturation and phase connectivity, and constant wettability, pore structure, and capillary number (∼10-4). The quadratic response for kr also shows excellent predictive capabilities.

Original languageEnglish (US)
Title of host publication16th European Conference on the Mathematics of Oil Recovery, ECMOR 2018
PublisherEuropean Association of Geoscientists and Engineers, EAGE
ISBN (Print)9789462822603
StatePublished - Jan 1 2018
Event16th European Conference on the Mathematics of Oil Recovery, ECMOR 2018 - Barcelona, Spain
Duration: Sep 3 2018Sep 6 2018

Publication series

Name16th European Conference on the Mathematics of Oil Recovery, ECMOR 2018

Other

Other16th European Conference on the Mathematics of Oil Recovery, ECMOR 2018
CountrySpain
CityBarcelona
Period9/3/189/6/18

All Science Journal Classification (ASJC) codes

  • Geotechnical Engineering and Engineering Geology
  • Geochemistry and Petrology
  • Energy Engineering and Power Technology

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