A Study of the Role of Microfractures in Counter-Current Spontaneous Imbibition by Lattice Boltzmann Simulation

Autor: Chaozhong Qin, Jianchao Cai, Yang Liu, Muhammad Sahimi
Rok vydání: 2020
Předmět:
Zdroj: Transport in Porous Media. 133:313-332
ISSN: 1573-1634
0169-3913
DOI: 10.1007/s11242-020-01425-w
Popis: During waterflooding, spontaneous imbibition is a fundamental recovery mechanism in fractured reservoirs. A large number of numerical and experimental studies have been devoted to understand the interaction mechanism between the matrix and the fractures at the core scale under various boundary conditions. Little attention has been paid, however, to the effect of microfractures on pore-scale spontaneous imbibition. In this study, five models with various types of microfractures, embedded in the same porous matrix, are used to investigate their role in counter-current spontaneous imbibition, using an optimized color-gradient lattice Boltzmann method. During the entire counter-current imbibition, the influence of the microfractures on the macro-recovery of the non-wetting fluid and the two-fluid interfaces, including the initial and local dynamics of the interfaces, and the evolution of the interface morphology, is analyzed in detail. The results indicate that microfractures have little influence on both the interfacial dynamics at the initial stage and the local interface dynamics in the matrix. The evolution of the interface morphology is, however, controlled by the geometric shape of the microfractures. In addition, the microfractures improve significantly the recovery of oil. The length of a single microfracture and the bifurcation angle of a microfracture bifurcated into two other microfractures affect significantly the recovery curve by influencing the evolution of the two-phase interface.
Databáze: OpenAIRE
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