Comprehensive evaluation technology for shale gas sweet spots in the complex marine mountains, South China: A case study from Zhaotong national shale gas demonstration zone

Liang, Xing; Wang, Gaocheng; Zhao, Xu; Zhang, Jiehui; Zhi-peng, Chen; Chen, Xian; Lü, Honghua; Liu, Chen; Zhao, Chunduan; Xiong, Shaoxiang

doi:10.1016/j.ngib.2016.02.003

Cited by 29 publications

(14 citation statements)

References 2 publications

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“…The porosity volume was estimated with P-velocity derived from prestack inversion. The lower bound of porosity for shale reservoirs in this prospect is 3% (Liang et al, 2016). Thus, only those sampling points with the porosity above 3% were included in the estimation of reservoir thickness.…”

Section: Prediction Methods Of Geologic Sweet Spotsmentioning

confidence: 99%

Prediction of sweet spots in shale reservoir based on geophysical well logging and 3D seismic data: A case study of Lower Silurian Longmaxi Formation in W4 block, Sichuan Basin, China

Sheng

Zhao

Ouyang

et al. 2016

Energy Exploration & Exploitation

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W4 block of Sichuan Basin is a pioneer in shale gas exploration and development in China. But geophysical prospecting is just at its beginning and thus has not provided enough information about how sweet spots distribute for the deployment of horizontal well. This paper predicted sweet spots based on logging and 3D seismic data. Well logging interpretation method was used to get the key evaluation parameters of shale reservoir and determine the distribution of sweet spots in vertical direction. Rock physics analysis technology was used to define the elastic parameters that were sensitive to the key evaluation parameters, such as TOC and gas content of shale gas reservoir. At the same time the quantitative relationships between them were established. Based on the result of seismic rock physics analysis, prestack inversion was carried out to predict the transverse plane distribution of the key evaluation parameters of shale reservoir. These research results are integrated to determine the distribution of sweet spots. The results show that sweet spots in this area were characterized by high TOC content, high gas content, high GR, high Young's modulus, low Poisson's ratio, low density, and low P-wave velocity. Density was the most sensitive elastic parameters to TOC of the reservoir. The optimal combination for predicting the gas content is composed of six parameters include density, Poisson's ratio, and so on. Sweet spots in this block vertically concentrate within 30 m above the bottom of Longmaxi Formation. Two classes of sweet

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Section: Prediction Methods Of Geologic Sweet Spotsmentioning

confidence: 99%

Prediction of sweet spots in shale reservoir based on geophysical well logging and 3D seismic data: A case study of Lower Silurian Longmaxi Formation in W4 block, Sichuan Basin, China

Sheng

Zhao

Ouyang

et al. 2016

Energy Exploration & Exploitation

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“…In the Sichuan Basin's hypoxic deep-water shelf environment, the moderately uplifted bathymetry, low-energy conditions, and low-sedimentation rate allowed for the accumulation of thick, widespread marine shale. This marine shale sequence includes the black graptolitic shale of the Longmaxi Formation [29]. Gamma values in the Sichuan Basin shale sequence peak in the Wufeng Formation (at the Ordovician-Silurian transition), before gradually decreasing upward.…”

Section: Regional Geological Settingmentioning

confidence: 99%

Reservoir Characteristics of the Lower Silurian Longmaxi Shale in Zhaotong Region, Southern China

et al. 2020

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The lower Silurian Longmaxi Formation hosts a highly productive shale gas play in the Zhaotong region of southern China. According to core observation, X-ray diffraction analyses, and scanning electron microscopy (SEM) observations, the shale comprises primarily quartz, carbonate minerals, and clay minerals, with minor amounts of plagioclase, K-feldspar, and pyrite. The clay mineral content ranges from 15.0% to 46.1%, with an average of 29.3% in the Zhaotong region. Organic geochemical analyses show that the Longmaxi Formation has good potential for shale gas resources by calculating total organic carbon, vitrinite reflectance, and gas content. Scanning electron microscope images demonstrate that reservoir pore types in the Longmaxi shale include organic pores, interparticle pores, intercrystalline pores, intraparticle pores, and fractures. Reservoir distribution is controlled by lithofacies, mineral composition, and geochemical factors. In addition, we investigated the relationships between reservoir parameters and production from 15 individual wells in the Zhaotong region by correlation coefficients. As a result, the brittleness index, total organic carbon (TOC), porosity, and gas content were used to define high-quality reservoirs in the Longmaxi shale. Based on these criteria, we mapped the thickness and distribution of high-quality reservoirs in the Longmaxi Formation and selected highlighted several key sites for future exploration and development.

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“…11 Among them, the Upper Yangtze Basin, where developed a wealth of marine organic-rich sediments during the Late Ordovician−Early Silurian, has great gas potential. 3,4 In the Upper Yangtze Basin, the well-known successful drilling operations penetrating the marine mudstone of Wufeng−Longmaxi formations are distributed in Changning, 12 Zhaotong, 13 Weiyuan, 14 and Jiaoshiba. 15,16 The recent drilling in Zheng'an County also demonstrated that the sediments of Wufeng−Longmaxi formations are the promising shale gas reservoir.…”

Section: Introductionmentioning

confidence: 99%

“…In the Upper Yangtze Basin, the well-known successful drilling operations penetrating the marine mudstone of Wufeng–Longmaxi formations are distributed in Changning, Zhaotong, Weiyuan, and Jiaoshiba. , The recent drilling in Zheng’an County also demonstrated that the sediments of Wufeng–Longmaxi formations are the promising shale gas reservoir . Although a large amount of research studying the sedimentary evolution and petrological and geochemical characteristics of Wufeng–Longmaxi formations has been conducted in different localities of the Upper Yangtze Basin, ,− a comprehensive evaluation of shale gas potential throughout the whole basin is still lacking.…”

Section: Introductionmentioning

confidence: 99%

Geochemical and Geological Characteristics of the Upper Ordovician–Lower Silurian Shales in the Upper Yangtze Basin, South China: Implication for the Shale Gas Exploration

et al. 2020

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Shale gas exploration in the Upper Yangtze Basin has been conducted for over ten years. The successful drillings in the region suggest that well-planned geological survey and reservoir evaluation are indispensable for the success of these drillings. In this study, the shale gas potential of Late Ordovician to Early Silurian mudstones/shales of the Wufeng–Longmaxi formations in the Upper Yangtze Basin was evaluated. First, all of the available geochemical and petrological data from Late Ordovician to Early Silurian mudstones/shales in the region were compiled. Distributional patterns of total organic carbon (TOC) values, thickness, thermal maturity, and burial depth of organic-rich mudstones/shales from the targeted formations were then analyzed. Our results show that TOC values range from 1.20 to 5.12%; R o values range from 1.92 to 2.86%; porosity varies from 0.77 to 9.2%; permeability varies from 0.015 to 1.99 md; the composition of quartz group of mineral component ranges from 18 to 85%, 59% in average; and clay mineral component ranges from 7 to 56%, 31% in average. Finally, based on these comprehensive analysis, three areas with great potential, that is, Luzhou-Xishui, western Chongqing, and Wulong-Shizhu, were selected as targets for further shale gas exploration and exploitation.

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Comprehensive evaluation technology for shale gas sweet spots in the complex marine mountains, South China: A case study from Zhaotong national shale gas demonstration zone

Cited by 29 publications

References 2 publications

Prediction of sweet spots in shale reservoir based on geophysical well logging and 3D seismic data: A case study of Lower Silurian Longmaxi Formation in W4 block, Sichuan Basin, China

Prediction of sweet spots in shale reservoir based on geophysical well logging and 3D seismic data: A case study of Lower Silurian Longmaxi Formation in W4 block, Sichuan Basin, China

Reservoir Characteristics of the Lower Silurian Longmaxi Shale in Zhaotong Region, Southern China

Geochemical and Geological Characteristics of the Upper Ordovician–Lower Silurian Shales in the Upper Yangtze Basin, South China: Implication for the Shale Gas Exploration

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