The Influence of Micro-Fractures on the Flow in Tight Oil Reservoirs Based on Pore-Network Models

Sun, Hai; Duan, Lian; Liu, Lei; Fan, Weipeng; Fan, Dongyan; Ye, Jun; Zhang, Lei; Yang, Yongfei; Zhao, Jianlin

doi:10.3390/en12214104

Cited by 16 publications

(10 citation statements)

References 36 publications

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“…The seepage process in microfractures under high pressure grouting is as follows: the cement slurry enters the microfracture under the action of grouting pressure, and the grout flows into the fracture and exerts force on the fracture surfaces on both sides [14,41]. Microfractures are opened due to the grouting pressure, allowing more cement slurry to enter the fracture channels.…”

Section: Mathematical Model Establishmentmentioning

confidence: 99%

“…Under high in situ stress and strong mining stress, surrounding rock masses commonly contain large amounts of fractures, including large-and medium-sized fractures as well as microfractures (fracture opening d ≤ 0:1 mm) [12][13][14]. With large deformation and continuous rheology of the surrounding rock, fractures in the rock mass are prone to squeezing and closing.…”

Section: Introductionmentioning

confidence: 99%

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Study on Seepage Simulation of High Pressure Grouting in Microfractured Rock Mass

Wang

Ren

et al. 2021

Geofluids

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In coal mines, under high in situ stress and strong mining activity, roadway surrounding rock commonly contains large amounts of larger fractures and microfractures. Along with the large deformation and continuous rheology of the soft rock roadway, the fractures in the surrounding rock are likely to be compressed and closed, forming undeveloped microfractures, which hinder conventional grouting support methods. Based on the fluid-solid coupling between slurry seepage and microfracture deformation, a theoretical model of microfracture grouting seepage is established. A program for the analysis and calculation of microfracture grouting is developed to quantitatively describe the variation in slurry seepage distance and fracture opening. Numerical experiments are carried out to study the grouting seepage of microfractures under different grouting pressures and fracture opening conditions, and the variation rules for the spatial distribution of fracture opening and slurry seepage distance during grouting pressure are obtained. Fluid-solid coupling has a significant influence on grout seepage characteristics. The grouting pressure and the fracture opening changes are nonlinearly attenuated along the grout seepage direction.

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Section: Mathematical Model Establishmentmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Study on Seepage Simulation of High Pressure Grouting in Microfractured Rock Mass

Wang

Ren

et al. 2021

Geofluids

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“…Tight-oil reservoirs are widely distributed around the world (e.g., [1,2]) and become a new prospect of hydrocarbon exploration and development [3,4]. Compared with conventional reservoirs, tight-oil rocks exhibit low porosity and permeability, a complex pore structure, and higher clay content [5][6][7]. Theoretical and experimental studies have shown that their permeability depends on microcracks [8][9][10][11], which significantly affect fluid flow [12][13][14][15] and the elastic properties [16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Elastic-Electrical Rock-Physics Template for the Characterization of Tight-Oil Reservoir Rocks

Pang¹,

Ba²,

Carcione

et al. 2021

Lithosphere

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Tight-oil reservoirs have low porosity and permeability, with microcracks, high clay content, and a complex structure resulting in strong heterogeneities and poor connectivity. Thus, it is a challenge to characterize this type of reservoir with a single geophysical methodology. We propose a dual-porosity-clay parallel network to establish an electrical model and the Hashin-Shtrikman and differential effective medium equations to model the elastic properties. Using these two models, we compute the rock properties as a function of saturation, clay content, and total and microcrack porosities. Moreover, a 3D elastic-electrical template, based on resistivity, acoustic impedance, and Poisson’s ratio, is built. Well-log data is used to calibrate the template. We collect rock samples and log data (from two wells) from the Songliao Basin (China) and analyze their microstructures by scanning electron microscopy. Then, we study the effects of porosity and clay content on the elastic and electrical properties and obtain a good agreement between the predictions, log interpretation, and actual production reports.

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“…After it is mixed with water, the cement particles are suspended in the slurry, forming a complex solid-liquid two-phase fluid. Due to the large particle size of the cement particles, the cement particles will block the entrance of the micro-fractures making it difficult to inject into the micro-fractures [13,14]. This phenomenon is called the percolation effect.…”

Section: Introductionmentioning

confidence: 99%

Understanding the Effect of Cementitious Grouting Pressure on Micro-Fracture Permeability for Rock Reinforcement Underground: A Lab Study

Wang

Ren

et al. 2020

Energies

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In grouting support projects, due to the small concealment of micro-fractures, the support effect often fails to meet design requirements. The percolation effect is a common factor that causes grouting failure, and the influence of grouting pressure on the percolation effect is very obvious. In this article, a design of a micro-fracture grouting experimental system is presented that can realize high-pressure grouting and then uses a variety of ultrafine cements to carry out high- and low-pressure grouting tests under different fracture opening conditions, thereby obtaining the grouting pressure and accumulated grouting weight during the grouting process. The results show that a combination of the grouting pressure curve and the cumulative grouting weight curve can determine whether the ultrafine cement will have a percolation effect. Increasing the grouting pressure can reduce the critical fracture opening value and also reduce the occurrence of the percolation effect. The research results provide a theoretical basis for the high-pressure grouting of micro-fracture rock masses and offer certain guiding significance for the design of high-pressure grouting support schemes.

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The Influence of Micro-Fractures on the Flow in Tight Oil Reservoirs Based on Pore-Network Models

Cited by 16 publications

References 36 publications

Study on Seepage Simulation of High Pressure Grouting in Microfractured Rock Mass

Study on Seepage Simulation of High Pressure Grouting in Microfractured Rock Mass

Elastic-Electrical Rock-Physics Template for the Characterization of Tight-Oil Reservoir Rocks

Understanding the Effect of Cementitious Grouting Pressure on Micro-Fracture Permeability for Rock Reinforcement Underground: A Lab Study

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