An understanding of oil–water replacement mechanism based on interfacial tension gradient during the well shut-in

Zhao, Chaoneng; Wang, Qiang; Zhao, Jinzhou; Hu, Yongquan; Liu, Anbang; He, Ping; Dong, Gao

doi:10.1016/j.egyr.2022.03.011

Cited by 5 publications

(3 citation statements)

References 29 publications

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“…Two articles deal with the relationship between the well shutin and production performance, a very heated topic for unconventional reservoirs in recent years. Zhao et al (2022a) derive a mathematical model of oil displacement driven by an interfacial tension gradient in an oil-wet capillary tube, and they consider the effects of osmotic pressure and hydraulic, mechanical dispersion to understand the imbibition during the well shut-in process in oil-wet unconventional rocks. Zhou et al (2022) use reservoir simulation to investigate the effect of fracturing fluid migration (with different shut-in times) on the well productivity, considering the clay damage in the fracture-face invaded zone.…”

Section: Contents Lists Available At Sciencedirectmentioning

confidence: 99%

Special issue “New advancements and challenges in unconventional reservoirs”

Davarpanah

Zhang

2023

Energy Reports

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Section: Contents Lists Available At Sciencedirectmentioning

confidence: 99%

Special issue “New advancements and challenges in unconventional reservoirs”

Davarpanah

Zhang

2023

Energy Reports

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“…Therefore, dispersion is determined by the phase distribution, which is affected by the various properties of both the porous media and fluid pairs. Such properties include the average displacement velocity (Løvoll et al., 2004), viscosity contrast (Larter et al., 2008; Lenormand, 1990), interfacial attention (Zhao et al., 2022), and wettability (Andrews et al., 2023; Hu et al., 2021; Y. Li et al., 2022). However, limited research has been conducted to characterize the impact of these factors on dispersion.…”

Section: Introductionmentioning

confidence: 99%

Impact of Oil Viscosity on Dispersion in the Aqueous Phase of an Immiscible Two‐Phase Flow in Porous Media: An X‐Ray Tomography Study

Li,

Nasir,

Wang

et al. 2023

Water Resources Research

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In this study, dispersion and mixing were studied in a steady two‐phase flow generated using a co‐injection method. The impact of oil viscosity was investigated over a large range of fluid viscosity ratios. The results indicate that highly heterogeneous flow fields are generated by a wide distribution of oil clusters with varied volumes. Variation in the velocity distribution enhanced the deformation and spreading of a tracer plume, resulting in large dispersion scales and accelerated spreading rates. The dispersion coefficients vary with time and exhibit a non‐Fickian dispersion during co‐injection. Consequently, anomalous mixing behaviors can be observed when the viscosity ratio exceeds 10. The mixing strength, characterized by the scalar dissipation rate, is first enhanced by distortion on the surface of the solute. Therefore, diffusion contributes to mixing, resulting in a faster decrease in the mixing strength in the late time regime. These results can be attributed to the fact that the non‐wetting fluid becomes disconnected, and the size of each cluster decreases as the oil viscosity increases. The formation of an oil film narrows pore spaces, and a lubrication effect of the oil film may contribute to the enhanced dispersion and mixing state, even with the low relative permeability of the wetting phase. This study provides insights into dispersion in partially saturated porous media with varied oil viscosities at both the macro and pore scales, which can further improve CO2 storage capacity and safety.This article is protected by copyright. All rights reserved.

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“…Since the introduction and application of hydraulic fracturing technology in previous decades, extensive research has been conducted on the damage of rock, propagation and evolution of hydraulic fracture (HF), migration of hydraulic fracturing proppant. The propagation of HF is always the focus of field engineers [13][14][15][16][17]. Due to lack of accurate and effective monitoring technology, it is impossible to directly observe the HF propagation process and morphology of underground reservoir [18].…”

Section: Introductionmentioning

confidence: 99%

Factors Controlling the Hydraulic Fracture Trajectory in Unconventional Reservoirs

et al. 2022

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The morphology of hydraulic fracture is affected by many factors. In previous studies, due to the heterogeneity of rock samples and the limitations of sample size, influence degree of various factors on fracture deflection angle has not been well distinguished in laboratory experiments. Based on the boundary element method, we established a mathematical model to study the factors controlling the morphology of hydraulic fracture. Simulation results show that with increasing injection pressure, the radius of the fracture curvature increases. When the difference between the injection pressure and the maximum principal stress is 5 times the ground stress difference, the influence of in situ stress on hydraulic fracture deflection can be ignored. Hydraulic fracture deflection angle was relatively larger when considering the viscosity of the fracturing fluid. When stress difference is too small or the injection pressure is too big, the deflection angle of fracture is easy to fluctuate during initial propagation. Too large Young’s modulus and too small Poisson’s ratio will inhibit the fracture deflection and cause a narrower width of fracture. The effect of Poisson’s ratio on fracture aperture is less than 1 mm. When perforation angle is perpendicular to maximum horizontal principal stress, the fracture width first increases rapidly and then gradually decreases from heel to tip. The influence degree of each factor on fracture deflection is ranked: stress difference of in-situ stress is the biggest, followed by injection pressure and perforation angle. This study is of great significance for the control of hydraulic fracture morphology and the further improvement of fracturing effect.

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An understanding of oil–water replacement mechanism based on interfacial tension gradient during the well shut-in

Cited by 5 publications

References 29 publications

Special issue “New advancements and challenges in unconventional reservoirs”

Special issue “New advancements and challenges in unconventional reservoirs”

Impact of Oil Viscosity on Dispersion in the Aqueous Phase of an Immiscible Two‐Phase Flow in Porous Media: An X‐Ray Tomography Study

Factors Controlling the Hydraulic Fracture Trajectory in Unconventional Reservoirs

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