A coupled matrix-fracture productivity calculation model considering low-velocity non-Darcy flow in shale reservoirs

Yan, Zhiming; Wang, Fengjiao; Liu, Yikun; Wang, Peng

doi:10.1016/j.fuel.2023.129845

Cited by 13 publications

(2 citation statements)

References 20 publications

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“…At present, energy exploitation is diversified, , and ASP flooding technology is often used to extract crude oil in the Daqing area. The ASP flooding technology is a technology that greatly improves oil recovery on the basis of alkali/polymer flooding and surfactant/polymer flooding.…”

Section: Introductionmentioning

confidence: 99%

Study on the Alkali-Free Three-Component Flooding System in the Daqing Oilfield

Liu,

Wu,

Chen

et al. 2024

ACS Omega

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ASP flooding is an important method to further improve oil recovery by a large margin. At present, it has entered the stage of industrial application, but there are still problems of scaling in the injection production system and high production maintenance costs. Based on the industrialized mature technology of weak alkali ASP flooding, sodium chloride is used to replace sodium carbonate, and the alkali-free three-component flooding (TC) system in the Daqing Oilfield is developed by mixing with petroleum sulfonate and partially hydrolyzed polyacrylamide. Based on the experiments of viscosity increasing, interface performance, stability, adsorption, and oil displacement effect, the differences between the alkali-free TC system and the weak alkali ASP system are compared and analyzed. The laboratory research results show that both systems are basically the same in terms of viscosity, viscoelasticity, shear resistance, interfacial activity, stability, and flowability. Due to the lack of alkaline water, the adsorption, emulsification, and oil displacement performance of the alkali-free TC system is slightly lower than that of the weak alkali ASP system. The recovery factor of core flooding can be increased by 27.31% over water flooding, which is 2.56 percentage points lower than that of the weak alkali ASP system. On the premise of the same 1% EOR effect, the agent cost of the alkali-free system is 17.02% lower than that of the alkali ASP system. This article innovatively verifies the feasibility of using NaCl instead of Na 2 CO 3 and explains the mechanism of significantly improving oil recovery in composite systems under alkali-free conditions from the ion level. However, the emulsification effect of the alkali-free TC system is relatively weak. The next step of research would be to consider adding an E-surfactant to enhance the emulsification performance of the composite system. By improving the system composition, technical references are provided for the efficient development of other terrestrial sandstone oilfields.

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Section: Introductionmentioning

confidence: 99%

Study on the Alkali-Free Three-Component Flooding System in the Daqing Oilfield

Liu,

Wu,

Chen

et al. 2024

ACS Omega

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“…Despite the gradual rise in the production of unconventional oil and gas resources, conventional subsurface methods remain the primary approach for oil and gas production [1,2]. Polymer flooding technology is widely recognized as the key technology for attaining elevated and consistent production levels in the Daqing Oilfield [3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Study on the Structure–Activity Relationship and Oil Displacement Characteristics of the Polysurfactant Agent

He,

Yuan,

Gan

et al. 2024

Polymers

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This study examines a versatile polymer known as polysurfactant, which is synthesized by co-polymerizing flexible acrylamide and sodium acrylate hydrocarbon chain. The polymer serves as a backbone and possesses active functional groups. Notably, the polysurfactant exhibits superior plugging and flooding abilities compared to conventional polymers. The primary objective of this paper is to investigate the properties and oil displacement characteristics of the polysurfactant through indoor physical simulation experiments. The results demonstrate that the multi-branched structure of the polysurfactant enhances its ability to associate, leading to the formation of a unique spatial network structure. The inclusion of multi-branched structures notably amplifies the association effect. The critical concentration for the association is estimated to be around 800 mg/L, at which juncture the polysurfactant exhibits a viscosity retention rate surpassing 90% subsequent to shearing. Furthermore, this spatial network structure exhibits self-recovery capabilities after experiencing shear failure and displaying strong viscosity and shear resistance. In addition, the concentration of the polysurfactant can control the hydrodynamic feature size, which shows its adaptability in regulation and oil-repelling functions at reservoir permeabilities ranging from 500 to 2000 × 10−3 μm2 with resistance coefficients ranging from 108 to 320. During the microscopic oil displacement process, the polysurfactant exerts a significant impact on mobility control, while the elastic pull clearly demonstrates a commendable viscoelastic oil displacement effect. The polysurfactant exhibits a specific degree of emulsification capability towards crude oil, leading to the emulsion exhibiting typical pseudoplastic fluid characteristics. The utilization of emulsification transportation and emulsification blockage contributes to the enhancement of oil recovery. As a result, the polysurfactant exhibits multifaceted capabilities, encompassing profile control, flooding, and plugging, owing to its unique structural characteristics. Through the implementation of a field test focused on flooding in the Daqing Oilfield, a significant enhancement in the recovery rate of 10.85% is observed, accompanied by a favorable input–output ratio of 1:3.86, thereby generating significant economic advantages.

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Review: Pre-Darcy flows in low-permeability porous media

Teng,

Li,

Chen

2024

Hydrogeol J

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The widely used Darcy’s law specifies a linear relation between the Darcy velocity of fluid flow and the pressure gradient that drives the flow. However, studies have shown that Darcy velocity can exhibit a nonlinear dependence on the pressure gradient in low-permeability porous media such as clay and shale when the pressure gradient is adequately low. This phenomenon is referred to as low-velocity non-Darcian flow or pre-Darcy flow. This paper provides a comprehensive review of the theories, experimental data, and modeling methods for pre-Darcy flow in low-permeability porous media. The review begins by outlining the fundamental mechanisms underlying pre-Darcy flow that regulate the unique characteristics such as nonlinear dependence of the Darcy velocity on the pressure gradient and its relevance to fluid–rock interactions. The review then proceeds to present a thorough compilation of experimental investigations performed in various low-permeability geomaterials including tight sandstones, shales, and clays. Next, empirical and theoretical models and simulation methods that have been developed to fit and interpret experimental data are reviewed. Finally, the review underscores the challenges encountered in conducting and interpreting pre-Darcy flow experiments and suggests future research directions. By analyzing previous experimental investigations, this review aims to offer a valuable resource for researchers and practitioners seeking to enhance their understanding of fluid dynamics in low-permeability geomaterials. This provides insights into the application of pre-Darcy flow in numerous natural and engineered processes such as shale oil and gas recovery, contaminant transport in low-permeability aquifers, and geological disposal of nuclear waste.

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A coupled matrix-fracture productivity calculation model considering low-velocity non-Darcy flow in shale reservoirs

Cited by 13 publications

References 20 publications

Study on the Alkali-Free Three-Component Flooding System in the Daqing Oilfield

Study on the Alkali-Free Three-Component Flooding System in the Daqing Oilfield

Study on the Structure–Activity Relationship and Oil Displacement Characteristics of the Polysurfactant Agent

Review: Pre-Darcy flows in low-permeability porous media

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