Pore scale investigation on scaling-up micro-macro capillary number and wettability on trapping and mobilization of residual fluid

Yao Wang; Rui Song; Jian-Jun Liu; Meng-Meng Cui; P G Ranjith

doi:10.1016/j.jconhyd.2019.103499

Pore scale investigation on scaling-up micro-macro capillary number and wettability on trapping and mobilization of residual fluid

J Contam Hydrol. 2019 Aug:225:103499. doi: 10.1016/j.jconhyd.2019.103499. Epub 2019 May 11.

Authors

Yao Wang¹, Rui Song², Jian-Jun Liu³, Meng-Meng Cui⁴, P G Ranjith⁵

Affiliations

¹ School of Geoscience and Technology, Southwest Petroleum University, Chengdu 610500, Sichuan, People's Republic of China. Electronic address: wangyao0927@126.com.
² School of Geoscience and Technology, Southwest Petroleum University, Chengdu 610500, Sichuan, People's Republic of China; State Key Laboratory of Geomechanics and Geotechnical Engineering, Wuhan Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, Hubei, People's Republic of China. Electronic address: songrui0506@126.com.
³ School of Geoscience and Technology, Southwest Petroleum University, Chengdu 610500, Sichuan, People's Republic of China; State Key Laboratory of Geomechanics and Geotechnical Engineering, Wuhan Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, Hubei, People's Republic of China.
⁴ School of Petroleum and Natural Gas Engineering, Southwest Petroleum University, Chengdu 610500, Sichuan, People's Republic of China.
⁵ Deep Earth Energy Research Laboratory, Department of Civil Engineering, Monash University, Melbourne, VIC 3800, Australia. Electronic address: ranjith.pathegama.gamage@monash.edu.

PMID: 31103927
DOI: 10.1016/j.jconhyd.2019.103499

Abstract

The mobilization mechanism of the trapped phases controlled by the viscous force and capillary force in porous media is crucial to various engineering applications. In this paper, pore scale water flooding process in rock models with nonuniform wettability is simulated by computational fluid dynamics (CFD) using the volume of fluid (VOF) model. Four types of rock are imaged by micro-CT (μ-CT) and adopted as inputs to generate the structured mesh models. The simulations of two-phase flow are carried out to study the immiscible displacement process in the development of oil fields. The scaling-up critical capillary number at micro-macro scale are acquired and validated, the effects of which on relative permeability, residual oil recovery and immiscible displacement efficiency are analyzed. The simulation results indicate that the critical capillary number at microscopic scale ranges from 10^-6 to 10^-5 for water-wetted and oil-wetted rock respectively, and approaches to 1 at the macro scale. The effect of wettability on oil recovery is positive for intermediate-wetted or weak water-wetted rock, while negative for strong wettability.

Keywords: Capillary number; Micro-CT; Nonuniform wettability; Pore-scale modeling; Relative permeability.

MeSH terms

Hydrodynamics*
Permeability
Porosity
Viscosity
Wettability