Developing a new hydrate saturation calculation model for hydrate-bearing sediments

Dong, Huaimin; Sun, Jianmeng; Zhu, Jinjiang; Liu, Lei; Lin, Zhenzhou; Golsanami, Naser; Cui, Likai; Yan, Weibo

doi:10.1016/j.fuel.2019.03.038

Cited by 58 publications

(21 citation statements)

References 25 publications

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“…The most popular approach for calculating the above-mentioned three parameters is the box counting method, fundamentals of which are represented in the published reports [46,47]. Fractal geometry theory has been used for characterizing the pore structure of conventional and unconventional reservoir rocks [20,[50][51][52], as well as gas hydrate-bearing sediments in recent years [26,[52][53][54][55][56]. According to a fundamental study of Pfeifer and Avnir [57] and as reported in the later applica-tions [58,59], in a fractal structure, the number of elements N has got a power-law relationship with the element's length scale r as…”

Section: Typical Groups Of Clay Minerals In Hydrocarbonmentioning

confidence: 99%

Fractal Properties of Various Clay Minerals Obtained from SEM Images

et al. 2021

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Clay minerals significantly alter the pore size distribution (PSD) of the gas hydrate-bearing sediments and sandstone reservoir rock by adding an intense amount of micropores to the existing intragranular pore space. Therefore, in the present study, the internal pore space of various clay groups is investigated by manually segmenting Scanning Electron Microscopy (SEM) images. We focused on kaolinite, smectite, chlorite, and dissolution holes and characterized their specific pore space using fractal geometry theory and parameters such as pore count, pore size distribution, area, perimeter, circularity, and density. Herein, the fractal properties of different clay groups and dissolution holes were extracted using the box counting technique and were introduced for each group. It was observed that the presence of clays complicates the original PSD of the reservoir by adding about 1.31-61.30 pores/100 μm2 with sizes in the range of 0.003-87.69 μm2. Meanwhile, dissolution holes complicate the pore space by adding 4.88-8.17 extra pores/100 μm2 with sizes in the range of 0.06-119.75 μm2. The fractal dimension ( D ) and lacunarity ( L ) values of the clays’ internal pore structure fell in the ranges of 1.51-1.85 and 0.18-0.99, respectively. Likewise, D and L of the dissolution holes were in the ranges of, respectively, 1.63-1.65 and 0.56-0.62. The obtained results of the present study lay the foundation for developing improved fractal models of the reservoir properties which would help to better understand the fluid flow, irreducible fluid saturation, and capillary pressure. These issues are of significant importance for reservoir quality and calculating the accurate amount of producible oil and gas.

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Section: Typical Groups Of Clay Minerals In Hydrocarbonmentioning

confidence: 99%

Fractal Properties of Various Clay Minerals Obtained from SEM Images

et al. 2021

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“…The electrical characteristics of reservoir rocks play an important role in the exploration and development of oil and gas resources [1][2][3][4]. Up to now, extensive research has been conducted on the electrical characteristics of rocks with intergranular porosity, achieving relatively good research results, mainly focused on the electrical characteristics of rocks with approximately homogeneous features in conventional oil and gas reservoirs [5][6][7][8], and did not pay much attention to fractured gas hydrate reservoirs [9][10][11], which consist of porous layers and fractured layers and mixed with gas hydrate that distribute in different pore habits [12][13][14][15]. However, gas hydrate, which was considered one of the most promising clean energy, is mainly distributed in deep-sea sediments and terrestrial permafrost [16][17][18].…”

Section: Introductionmentioning

confidence: 99%

A Study on the Electrical Characteristics of Fractured Gas Hydrate Reservoirs Based on Digital Rock Technology

Xue²,

Xianghui³

et al. 2021

Lithosphere

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The electrical characteristics of fractured gas hydrate reservoirs were investigated through the diffusion-limited aggregation model, digital rock technology, and the finite element method. The results show that the fracture and gas hydrate have a significant effect on the electrical characteristics of rock partially saturated with gas hydrate, where the matrix pore and fracture mixed gas hydrate form a dual-porosity system. Due to the fracture and gas hydrate effect, the electrical characteristics of fractured gas hydrate reservoirs cannot be described well by traditional Archie equations. The resistivity index vs. water saturation curve of fractured gas hydrate reservoirs shows a nonlinear relationship for different gas hydrate pore habits (pore-filling, cementing, and grain-coating types), and this curve consists of two parts with different gas hydrate saturation exponents for pore-filling and cementing gas hydrate and presents a curve without a fixed water saturation exponent for grain-coating gas hydrate. Fractured gas hydrate reservoirs with different fracture apertures, different gas hydrate pore habits, and saturation features will lead to macroscopic electrical anisotropy. The results of theoretical analysis and numerical simulation show that the electrical anisotropy coefficient of fractured gas hydrate reservoirs is a function of gas hydrate saturation. The function curve consists of three segments with the turning point for pore-filling and cementing gas hydrate, and this curve can be divided into two parts through the turning point. The findings of this study can help for a better understanding of the electrical characteristics of fractured gas hydrate reservoirs, which have great significance for the exploration and development of gas hydrate resources.

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“…Several industrial oil resources have been found in the shale of the Eocene‐Oligocene E s 3 and E s 4 of the Shahejie Formation 8,9 . The pore structure of reservoir rock dominates the electrical properties, elastic properties, storage properties, and transmission characteristics of rock 10‐18 . Thus, it has a significant influence on the hydrocarbon exploration and development of the area.…”

Section: Introductionmentioning

confidence: 99%

A 3D FIB‐SEM technique for quantitative characterization of oil shale's microstructure: A case study from the Shahejie Formation in Dongying Depression, China

Zhao

Dong

Zhang

et al. 2020

Energy Science & Engineering

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Investigating the pore structure of shale rocks plays an important role in understanding the mechanism of shale oil accumulation and migration; thus, it has a notable influence on the exploration and development of shale oil resources. In the present study, the microstructure of oil shale samples extracted from the Shahejie Formation in the Dongying Depression was investigated through the joint usage of focused ion beam (FIB) and scanning electron microscopy (SEM). Herein, we selected four representative samples. The SEM images of the sample surfaces milled by FIB indicated that pores were found in both the organic and inorganic matter. Organic pores were less developed in the samples because of the low thermal maturity of the organic matter. Continuous 3D digital rock images of shale samples were generated by FIB grinding and SEM in situ imaging. Based on multithreshold segmentation, the shale rocks were separated into different parts including kerogen, inorganic matter, and pores. The pore connectivity and pore size distributions were analyzed via Avizo software and in‐house developed MATLAB scripts. The pore size and corresponding volume distributions suggested that mesoscale pores (2‐50 nm) were abundant in the samples but they contributed limitedly to the total pore volume. Macropores (>50 nm) accounted for a small proportion but they had a greater contribution to the overall pore space volume. The coordination numbers of the subject four samples were mainly 0 and 1, which means that isolated pores accounted for the vast majority of the pores. These observations are critical to conduct reliable petrophysical simulations in the oil shales and understand their intrinsic properties accurately.

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Developing a new hydrate saturation calculation model for hydrate-bearing sediments

Cited by 58 publications

References 25 publications

Fractal Properties of Various Clay Minerals Obtained from SEM Images

Fractal Properties of Various Clay Minerals Obtained from SEM Images

A Study on the Electrical Characteristics of Fractured Gas Hydrate Reservoirs Based on Digital Rock Technology

A 3D FIB‐SEM technique for quantitative characterization of oil shale's microstructure: A case study from the Shahejie Formation in Dongying Depression, China

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