Lacustrine tight oil accumulation characteristics: Permian Lucaogou Formation in Jimusaer Sag, Junggar Basin

Cao, Zhe; Liu, Guangdi; Kong, Yali; Wang, Chengyun; Niu, Zicheng; Zhang, Jingya; Geng, Changbo; Shan, X.; Wei, Zhipeng

doi:10.1016/j.coal.2015.11.004

Cited by 152 publications

(58 citation statements)

References 23 publications

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“…With the successful application of horizontal drilling and multistage hydraulic fracturing technology, tight oil such as Bakken oil (Williston basin, North America) and Eagle Ford oil (South Texas, USA) had been exploited commercially. It had become the focus of research in global petroleum geology1 and was considered as the most practical unconventional replacement for oil and gas besides shale gas2. Tight sandstones and shale had stored a considerable amount of hydrocarbon in their structures.…”

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confidence: 99%

Pore structure characterization of Chang-7 tight sandstone using MICP combined with N2GA techniques and its geological control factors

Cao

Liu

Zhan

et al. 2016

Sci Rep

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106

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Understanding the pore networks of unconventional tight reservoirs such as tight sandstones and shales is crucial for extracting oil/gas from such reservoirs. Mercury injection capillary pressure (MICP) and N2 gas adsorption (N2GA) are performed to evaluate pore structure of Chang-7 tight sandstone. Thin section observation, scanning electron microscope, grain size analysis, mineral composition analysis, and porosity measurement are applied to investigate geological control factors of pore structure. Grain size is positively correlated with detrital mineral content and grain size standard deviation while negatively related to clay content. Detrital mineral content and grain size are positively correlated with porosity, pore throat radius and withdrawal efficiency and negatively related to capillary pressure and pore-to-throat size ratio; while interstitial material is negatively correlated with above mentioned factors. Well sorted sediments with high debris usually possess strong compaction resistance to preserve original pores. Although many inter-crystalline pores are produced in clay minerals, this type of pores is not the most important contributor to porosity. Besides this, pore shape determined by N2GA hysteresis loop is consistent with SEM observation on clay inter-crystalline pores while BJH pore volume is positively related with clay content, suggesting N2GA is suitable for describing clay inter-crystalline pores in tight sandstones.

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confidence: 99%

Pore structure characterization of Chang-7 tight sandstone using MICP combined with N2GA techniques and its geological control factors

Cao

Liu

Zhan

et al. 2016

Sci Rep

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106

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“…Stratigraphic column of the Permian Lucaogou Formation in the Jimusar Sag, Junggar Basin (modified from Kuang et al, ; Cao et al, ). In the column 6: (a) 3152.45–3152.6 m, silty carbonaceous mudstone; (b) 3152.54 m, silty carbonaceous mudstone, 1.…”

Section: Geological Settingmentioning

confidence: 99%

Geochemical and geological characteristics of Permian Lucaogou Formation shale of the well Ji174, Jimusar Sag, Junggar Basin, China: Implications for shale oil exploration

Pang

Wang

et al. 2017

Geological Journal

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Abundant shale oil resources were recently found in the organic‐rich Permian Lucaogou (P2l) Formation shale, Jimusar Sag, Junggar Basin. Although some scholars have conducted some researches on the basic geochemical characteristics of the Lucaogou Formation shale, it is not enough to effectively guide the shale oil exploration in the area. This is because during the exploration process of shale oil, besides the basic geochemical characteristics of shale, its mineral composition, physical properties, and oil‐bearing characteristics are all very important evaluation parameters. To systematically evaluate the favourable shale oil exploration sections in the Lucaogou Formation, 265 pieces of shale cores were sampled from well Ji174 in this study. Besides the basic geochemical characteristics of the 265 pieces of cores, the mineralogical, petrophysical, and oil‐bearing characteristics were also analysed. Results show that the shale has abundant organic matter (average total organic carbon 3.51%, average petroleum generation potential 15.67 mg/g), dominated by Type II1 and Type II2 kerogen, and has entered the early‐mature to mature stage. The Upper Member of the Lucaogou Formation has relatively higher organic matter and organic matter type is relatively more oil prone compared to the Lower Member; however, organic matter thermal maturity is lower. The P2l Formation shale is characterized by high carbonate minerals and low clay minerals, and when considering mineralogical brittleness, both the Upper and Lower members are ideally fracturable in shale oil development. The P2l Formation shale has a wide porosity range (1.1–13.9%), and the Lower Member's porosity is slightly greater. The inversion of shale porosity in the P2l Formation is controlled by the differentiated mineral composition. The oil saturation index values of the Lower Member shale are significantly greater than the Upper Member shale. From the above, the Lower Member of the P2l Formation shale is ideally suited and has greater shale oil potential in the Jimusar Sag, Junggar Basin, especially in the depth intervals of 3,255–3,272, 3,282–3,298, and 3,317–3,334 m in the well Ji174.

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“…Therefore, to clarify the organic matter accumulation mechanism in a lacustrine rift basin, it is important to characterize organic matter sources, depositional paleoenvironment, and water column properties. Organic geochemical parameters and elemental geochemistry are effective methods because they can provide vast information about organic matter source, climate condition, primary productivity, and redox conditions (Cao, Liu, et al, ; Ding et al, ; Fu, Wang, Zeng, Tan, & Feng, ; Hao et al, ; Harris, Freeman, Pancost, White, & Mitchell, ; Jia, Bechtel, et al, ; Ma, Wang, Lv, Li, & Yi, ; Makeen, Hakimi, & Abdullah, ; Quan et al, ; Sarki Yandoka, Abdullah, Abubakar, Hakimi, & Adegoke, ).…”

Section: Introductionmentioning

confidence: 99%

Geochemical characteristics, depositional environment, and controlling factors of Lower Cretaceous shales in Chagan Sag, Yingen‐Ejinaqi Basin

et al. 2017

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The Lower Cretaceous shales of Chagan Sag, Yingen‐Ejinaqi Basin, are considered as the source rocks of hydrocarbons discovered in the sag. Borehole shales from the Lower Cretaceous were subjected to comprehensive geochemical study to evaluate the quality of source rock, to reconstruct the paleodepositional environment and to determine the controlling factors of organic matter enrichment. Content of present‐day total organic carbon, and hydrogen index, averaging 1.4% and 259.2 mg hydrocarbon/g total organic carbon, respectively reveal poor to fair quality of organic matter. Average value of vitrinite reflectance (Ro) of 1.0% indicates mature organic matter. Maceral composition and biomarker analysis provide evidence for a mixed aquatic and terrigeous organic matter input. Based on Sr/Cu, Sr/Ba, and gammacerane index, we propose that organic matter was deposited in closed hypersaline under hot and arid climate conditions. The ratios of V/(V + Ni), and pristane/phytane (Pr/Ph), as well as the presence of β‐carotene suggest a stratified water column with anoxic bottom water condition. Low to moderate productivity as a result of deficient nutrient supply, the excellent organic matter preservation condition under stratified anoxic water column and high sedimentary rate controlled the quality of source rock. In addition, influence of factors such as content of clay minerals on organic matter enrichment cannot be ignored.

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Lacustrine tight oil accumulation characteristics: Permian Lucaogou Formation in Jimusaer Sag, Junggar Basin

Cited by 152 publications

References 23 publications

Pore structure characterization of Chang-7 tight sandstone using MICP combined with N2GA techniques and its geological control factors

Pore structure characterization of Chang-7 tight sandstone using MICP combined with N2GA techniques and its geological control factors

Geochemical and geological characteristics of Permian Lucaogou Formation shale of the well Ji174, Jimusar Sag, Junggar Basin, China: Implications for shale oil exploration

Geochemical characteristics, depositional environment, and controlling factors of Lower Cretaceous shales in Chagan Sag, Yingen‐Ejinaqi Basin

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