The characteristics and influencing factors of permeability stress sensitivity of tight sandstone reservoirs

Zhong, Xinyu; Zhu, Yushuang; Liu, Liping; Hong-mei, Yang; Li, Yunfeng; Xie, Ying; Liu, Linyu

doi:10.1016/j.petrol.2020.107221

Cited by 43 publications

(22 citation statements)

References 22 publications

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“…The comparison between calculated results and experimental results are seen in Figures 2 and 3 and Tables 3 and 4. Figure 2 shows the comparison between initial permeability calculated by the proposed model and that found in experiments in the works of Liu et al [48] and Zhong et al [49]. From Figure 2, we can see that the initial permeability is consistent with that found in experiments in the works of Liu et al [48] and Zhong et al [49].…”

Section: Fractal Permeability Model Verificationsupporting

confidence: 79%

“…Figure 2 shows the comparison between initial permeability calculated by the proposed model and that found in experiments in the works of Liu et al [48] and Zhong et al [49]. From Figure 2, we can see that the initial permeability is consistent with that found in experiments in the works of Liu et al [48] and Zhong et al [49]. The relative errors ranged from 0 to 3.85%, which is less than 5%.…”

Section: Fractal Permeability Model Verificationsupporting

confidence: 74%

“…In this section, we present verifications of the fractal permeability model by comparing it with published experimental results and models. Liu et al [48] and Zhong et al [49] conducted permeability stress sensitivity evaluation experiments of tight reservoirs by means of core flooding, thin-section analysis, and the nuclear magnetic resonance/high-pressure mercury intrusion. The core's parameters in the works of Liu et al [48] and Zhong et al [49] are given in Table 1.…”

Section: Fractal Permeability Model Verificationmentioning

confidence: 99%

“…Liu et al [48] and Zhong et al [49] conducted permeability stress sensitivity evaluation experiments of tight reservoirs by means of core flooding, thin-section analysis, and the nuclear magnetic resonance/high-pressure mercury intrusion. The core's parameters in the works of Liu et al [48] and Zhong et al [49] are given in Table 1. By combining the data in Table 1 and Equations ( 3) and ( 8)-( 10), we could obtain the pore fractal dimension and the tortuosity fractal dimension seen in Table 2.…”

Section: Fractal Permeability Model Verificationmentioning

confidence: 99%

See 3 more Smart Citations

A Fractal Permeability Model of Tight Oil Reservoirs Considering the Effects of Multiple Factors

Cui

Yang

et al. 2022

Fractal Fract

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The prediction of permeability and the evaluation of tight oil reservoirs are very important to extract tight oil resources. Tight oil reservoirs contain enormous micro/nanopores, in which the fluid flow exhibits micro/nanoscale flow and has a slip length. Furthermore, the porous size distribution (PSD), stress sensitivity, irreducible water, and pore wall effect must also be taken into consideration when conducting the prediction and evaluation of tight oil permeability. Currently, few studies on the permeability model of tight oil reservoirs have simultaneously taken the above factors into consideration, resulting in low reliability of the published models. To fill this gap, a fractal permeability model of tight oil reservoirs based on fractal geometry theory, the Hagen–Poiseuille equation (H–P equation), and Darcy’s formula is proposed. Many factors, including the slip length, PSD, stress sensitivity, irreducible water, and pore wall effect, were coupled into the proposed model, which was verified through comparison with published experiments and models, and a sensitivity analysis is presented. From the work, it can be concluded that a decrease in the porous fractal dimension indicates an increase in the number of small pores, thus decreasing the permeability. Similarly, a large tortuous fractal dimension represents a complex flow channel, which results in a decrease in permeability. A decrease in irreducible water or an increase in slip length results in an increase in flow space, which increases permeability. The permeability decreases with an increase in effective stress; moreover, when the mechanical properties of rock (elastic modulus and Poisson’s ratio) increase, the decreasing rate of permeability with effective stress is reduced.

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Section: Fractal Permeability Model Verificationsupporting

confidence: 79%

Section: Fractal Permeability Model Verificationsupporting

confidence: 74%

Section: Fractal Permeability Model Verificationmentioning

confidence: 99%

Section: Fractal Permeability Model Verificationmentioning

confidence: 99%

See 2 more Smart Citations

A Fractal Permeability Model of Tight Oil Reservoirs Considering the Effects of Multiple Factors

Cui

Yang

et al. 2022

Fractal Fract

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“…Experimental Methods. At present, there are two main experimental methods for investigating stress sensitivity in the laboratory: the variable confining pressure method and the variable fluid pressure method [33][34][35][36]. In the variable confining pressure method, the confining pressure is…”

Section: Experimental Materials and Methodsmentioning

confidence: 99%

Influence of Microcracks on Stress Sensitivity in Tight Sandstone

Zhang

et al. 2021

Lithosphere

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Stress sensitivity occurs throughout the reservoir development process, especially in the study of low permeability tight reservoir, considering the influence of stress sensitivity is particularly important. When studying stress sensitivity, the current main experimental methods are variable confining pressure and variable fluid pressure methods, but they cannot simulate the stress sensitivity during water injection development. Therefore, in this paper, an experimental stress sensitivity method that can be used to study the depletion mining and water injection development processes is established. In addition, the influence of different degrees of microcrack development on the stress sensitivity of the reservoir is investigated. The results of this study show that under the experimental conditions described in this article, the loading of axial compression plays a role of preloading stress and realizes the whole process of stress sensitivity under the condition that the fluid pressure is lower than the confining pressure. In the experiment, the permeability growth rate of matrix cores does not exceed 20%. For cores containing microcracks, when the axial pressure was less than 30 MPa, the permeability slowly increased with increasing fluid pressure. When the axial pressure was 30 MPa, the permeability changes are mainly divided into two stages. In the first stage, the microcracks are closed under compressive stress. At this time, the microcracks have a limited impact on the seepage capacity. The permeability increases slowly with increasing fluid pressure. In the second stage, the permeability rapidly increases after the microcracks open. These two stages can be described by two straight lines. The slope of the first line has nothing to do with the development of microcracks; the higher the degree of microcrack development, the greater the slope of the straight line of the second stage. For all of the cores, the permeability decreases as the axial pressure increases.

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Pore‐throat structure characteristics and fluid mobility analysis of tight sandstone reservoirs in Shaximiao Formation, Central Sichuan

et al. 2023

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The pore‐throat structure and fluid mobility are the key factors of tight sandstone reservoir classification and evaluation. Taking the Jurassic Shaximiao Formation tight sandstone reservoir in Central Sichuan Basin as an example, 19 samples were analysed by casting thin sections, scanning electron microscopy, high‐pressure mercury injection and nuclear magnetic resonance to clarify the pore‐throat structure, the fluid motility and its controlling factors. The results show that the pore type of Shaximiao Formation tight sandstone reservoir consist of intergranular pores, dissolved pores and a few microfractures. Based on the feature of capillary pressure curve, the pore‐throat structure was classified into three types, corresponding to different movable fluid characteristics. The Type I has large pore and throat radius, good pore‐throat connectivity, small fractal dimension, weak reservoir heterogeneity and strong fluid motility. The distribution range of pore‐throat radius is mainly from 0.3 to 1.1 μm and the average movable fluid porosity (MFP) and movable fluid saturation (MFS) are 6.04% and 49.93%. The Type II has poor pore‐throat sorting, weak fluid motility and the distribution range of pore‐throat radius is 0.01–0.03 μm and 0.2–0.8 μm. The average MFP and MFS of Type II are 1.13% and 14.3%. The Type III has the smallest pore‐throat radius and the largest fractal dimension, corresponding to the most complex pore‐throat structure, which lead to the worst fluid mobility. The average MFP and MFS are 0.49% and 12.76%. The fluid mobility of the tight sandstone reservoir is affected by physical properties and pore‐throat structure. The reservoirs with large pore‐throat size, good connectivity between pore and throat, and low heterogeneity have higher MFP and saturation. Moreover, the mineral compositions have different effects on fluid mobility of the tight sandstone. The feldspar positively affects fluid mobility, while the clay minerals negatively affect fluid mobility.

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The characteristics and influencing factors of permeability stress sensitivity of tight sandstone reservoirs

Cited by 43 publications

References 22 publications

A Fractal Permeability Model of Tight Oil Reservoirs Considering the Effects of Multiple Factors

A Fractal Permeability Model of Tight Oil Reservoirs Considering the Effects of Multiple Factors

Influence of Microcracks on Stress Sensitivity in Tight Sandstone

Pore‐throat structure characteristics and fluid mobility analysis of tight sandstone reservoirs in Shaximiao Formation, Central Sichuan

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