A novel method to estimate subsurface shale gas capacities

Huang, Hexin; Sun, Wei; Xiong, Fengyang; Chen, Lei; Li, Xin; Gao, Tian; Jiang, Zhenxue; Ji, Wei; Wu, Yanjun; Han, Jin

doi:10.1016/j.fuel.2018.05.172

Cited by 35 publications

(16 citation statements)

References 29 publications

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“…(a) China map; (b) the amplification map of the green part in (a). 2 Geofluids this area is very important to greatly increase the natural gas production [14]. The main experimental samples are presented in Table 1.…”

Section: Samples and Experimental Methodsmentioning

confidence: 99%

“…With increasing energy requirement, unconventional natural gas attracts our attention [1][2][3][4][5][6][7][8][9]. Tight sand reservoirs belong to unconventional reservoirs and have low porosity and permeability [10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

“…Ordos basin has abundance of tight gas, such as in the Sulige area. Ordos basin is the second largest hydrocarbon-bearing onshore basin in China with an area of about 250000 km 2 [14]. Lots of work has been carried out to learn tight reservoir and to effectively develop it.…”

Section: Introductionmentioning

confidence: 99%

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Analyzing Tight Sand Characteristics and Its Influence on Aqueous Phase Removal by Gas Displacement

Meng

Shen

et al. 2019

Geofluids

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Tight sand gas is an important unconventional natural gas. Liquid filtration plays a main role in the formation damage. Flowback rate is closely related to the formation permeability recovery. Usually, the more flowback rate is, the better the permeability recovery is. In order to research the factors that influence the liquid flowback, the tight sand characteristics and gas displacement have been investigated. Some experiments were carried out, including porosity, permeability, XRD, casting thin section, SEM, stress sensitivity, rock expansion, and gas displacement. The results are shown as follows. Taiyuan formation has average high clay content than H8 formation. Illite is the main clay in Taiyuan formation; chlorite is the main clay in H8 formation. From the casting thin section, the rock has strong compression. Taiyuan formation has large pore. However, H8 formation mainly has small cracks. Through the SEM, there are many micro- to nanocracks as well as some pores in these two formations. In some cases, cracks penetrate the clays. From the permeability stress sensitivity, these tight sands have strong stress sensitivity. Permeability decreases quickly with increasing confining pressure. In the rock expansion experiment, the tight sand has less expansion rate compared with shale gas rock and volcanic gas rock. Rock expansion rate has positive relationship with clay content. In the gas displacement experiment, usually the higher the clay content, the lesser the liquid flowback. Some samples have high clay content. However, it has high flowback rate, which may account for good pore connection. Through the above study, the flowback rate has negative relationship with clay content and positive relationship with pore size, pore connection, and displacement pressure. In order to increase tight gas production in the study area, the formation should have high flowback rate and less liquid retention. Therefore, clay expansion preventing additives should be added into the fracturing liquid to reduce the liquid retention. The quick flowback should be implemented after hydraulic fracturing for reducing the interaction between liquid and rock. At the same time, the drawdown pressure should keep in a certain value to reduce stress sensitivity.

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Section: Samples and Experimental Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Analyzing Tight Sand Characteristics and Its Influence on Aqueous Phase Removal by Gas Displacement

Meng

Shen

et al. 2019

Geofluids

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“…So far, plenty of wells have obtained industrial gas flow with the average gas content of 4000 m 3 /d, and fracturing technology has also made breakthroughs and innovative progress. The great shale gas content and industrial gas flow demonstrate the large potential of shale gas resource in Yanchang formation in the Ordos Basin, also indicate a great prospect for further exploration and development [25]. Though the primary production of continental shale gas is usually lower than that of predicted gas potential especially when compared to marine shale gas, the stable production time maybe longer, and with the advance of fracturing technology, the scale production can be expected in the future.…”

Section: Evaluation Of Shale Gas Adsorption Capacity Of Yanchang Formmentioning

confidence: 99%

Influencing Factors and Mathematical Prediction of Shale Adsorbed Gas Content in the Upper Triassic Yanchang Formation in the Ordos Basin, China

et al. 2019

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Evaluating absorbed gas content (AGC) in shales is crucial for accurately characterizing shale gas reservoirs and calculating resource potential. To investigate geological factors influencing AGC, 15 shale samples collected from the Yanchang Formation underwent related experiments. Then geochemistry features, mineral compositions, pore structure parameters and external factors were analyzed. The actual AGC was calculated using the Langmuir equation. Single geological factors acting on the AGC were discussed by the single-factor correlation analysis. Finally, four main influence factors (total organic carbon, S1, quartz content and formation temperature) were selected out from the 12 influence factors to establish the mathematical prediction model through the multi-factor regression statistical analysis method using SPSS software. The model was verified as being reliable with R2 as high as 0.8046 and relative error less than ±20%. Comparisons show that both the CH4 isothermal adsorption experimental method and the multi-factor regression analysis method have their own applicability and disadvantages, and they can complement each other in evaluating AGC in shales. Synthetic evaluation of AGC indicates that the Yanchang shale has an overall moderate AGC occupying about 58% of the total, which is helpful to extend shale gas production time of the Yanchang reservoir. Though under the present conditions, economic benefits of the continental shale gas are not obvious, the shale resource potential of Yanchang formation can’t be ignored.

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“…With a severe energy shortage situation, increasing shale gas has received more attention worldwide, and a global astounding “shale gas green revolution” is booming in the past few years. More than 20 countries except for the North America are conducting prophase evaluation and pilot test of shale gas exploration and development, especially in China [1,2,3,4,5]. Shale gas resource has already become a natural gas production target with great potential and of great significance.…”

Section: Introductionmentioning

confidence: 99%

Nanopore Structure and Fractal Characteristics of Lacustrine Shale: Implications for Shale Gas Storage and Production Potential

Chen

Jiang

et al. 2019

Nanomaterials

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In order to better understand nanopore structure and fractal characteristics of lacustrine shale, nine shale samples from the Da’anzhai Member of Lower Jurassic Ziliujing Formation in the Sichuan Basin, southwestern (SW) China were investigated by total organic carbon (TOC) analysis, X-ray diffraction (XRD) analysis, field emission scanning electron microscopy (FE-SEM), and low-pressure N2 adsorption. Two fractal dimensions D1 and D2 (at the relative pressure of 0–0.5 and 0.5–1, respectively) were calculated from N2 adsorption isotherms using the Frenkel–Halsey–Hill (FHH) equation. The pore structure of the Lower Jurassic lacustrine shale was characterized, and the fractal characteristics and their controlling factors were investigated. Then the effect of fractal dimensions on shale gas storage and production potential was discussed. The results indicate that: (1) Pore types in shale are mainly organic-matter (OM) and interparticle (interP) pores, along with a small amount of intraparticle (intraP) pores, and that not all grains of OM have the same porosity. The Brunauer–Emmett–Teller (BET) surface areas of shale samples range from 4.10 to 8.38 m2/g, the density-functional-theory (DFT) pore volumes range from 0.0076 to 0.0128 cm3/g, and average pore diameters range from 5.56 to 10.48 nm. (2) The BET surface area shows a positive correlation with clay minerals content and quartz content, but no obvious relationship with TOC content. The DFT pore volume shows a positive correlation with TOC content and clay minerals content, but a negative relationship with quartz content. In addition, the average pore diameter shows a positive correlation with TOC content and a negative relationship with quartz content, but no obvious relationship with clay minerals content. (3) Fractal dimension D1 is mainly closely associated with the specific surface area of shale, suggesting that D1 may represent the pore surface fractal dimension. Whereas fractal dimension D2 is sensitive to multiple parameters including the specific surface area, pore volume, and average pore diameter, suggesting that D2 may represent the pore structure fractal dimension. (4) Shale with a large fractal dimension D1 and a moderate fractal dimension D2 has a strong capacity to store both adsorbed gas and free gas, and it also facilitates the exploitation and production of shale gas.

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A novel method to estimate subsurface shale gas capacities

Cited by 35 publications

References 29 publications

Analyzing Tight Sand Characteristics and Its Influence on Aqueous Phase Removal by Gas Displacement

Analyzing Tight Sand Characteristics and Its Influence on Aqueous Phase Removal by Gas Displacement

Influencing Factors and Mathematical Prediction of Shale Adsorbed Gas Content in the Upper Triassic Yanchang Formation in the Ordos Basin, China

Nanopore Structure and Fractal Characteristics of Lacustrine Shale: Implications for Shale Gas Storage and Production Potential

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