Formation, distribution, resource potential, and discovery of Sinian–Cambrian giant gas field, Sichuan Basin, SW China

Zou, Caineng; Du, Jiapei; Xu, Chao; Wang, Zecheng; Zhang, Baomin; Wei, Guoqi; Wang, Tongshan; G, Yao; Deng, Shuai; Liu, Jingjiang; Zhou, Hui; Xu, Aiqiang; Zhi, Yang; Jiang, Hua; Gu, Zhidong

doi:10.1016/s1876-3804(14)60036-7

Cited by 330 publications

(139 citation statements)

References 7 publications

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“…The depositional environments of the source rocks were mainly deep-water restricted conditions inside shelves and slopes (Zhang et al 2005). In the basins with giant oil and gas fields, Riphean source rocks were developed in the Siberian plate (East Siberian Basin), and Sinian source rocks were mostly deposited in the Yangtze plate and the eastern margin of the Arabian plate (Oman Basin) (Liang et al 2006;Liu et al 2006;Tao et al 2012;Nicholas and Gold 2012;Zou et al 2014a). Because of the rise in sea level resulting from warmer climate and rapidly melting glaciers as the glacial period turned into the postglacial period, Cambrian, Ordovician, and Silurian source rocks were deposited (Zhang et al 2005 Torsvik 2011, 2013); and Silurian source rocks were mainly deposited in Laurentia (Michigan Basin) (Klemme and Ulmishek 1991;Zhou et al 2014).…”

Section: Source Rocksmentioning

confidence: 99%

Formation and distribution characteristics of Proterozoic–Lower Paleozoic marine giant oil and gas fields worldwide

et al. 2017

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There are rich oil and gas resources in marine carbonate strata worldwide. Although most of the oil and gas reserves discovered so far are mainly distributed in Mesozoic, Cenozoic, and upper Paleozoic strata, oil and gas exploration in the Proterozoic-Lower Paleozoic (PLP) strata-the oldest marine strata-has been very limited. To more clearly understand the oil and gas formation conditions and distributions in the PLP marine carbonate strata, we analyzed and characterized the petroleum geological conditions, oil and gas reservoir types, and their distributions in thirteen giant oil and gas fields worldwide. This study reveals the main factors controlling their formation and distribution. Our analyses show that the source rocks for these giant oil and gas fields are mainly shale with a great abundance of type I-II organic matter and a high thermal evolution extent. The reservoirs are mainly gas reservoirs, and the reservoir rocks are dominated by dolomite. The reservoir types are mainly karst and reef-shoal bodies with well-developed dissolved pores and cavities, intercrystalline pores, and fractures. These reservoirs are highly heterogeneous. The burial depth of the reservoirs is highly variable and somewhat negatively correlated to the porosity. The cap rocks are mainly thick evaporites and shales, with the thickness of the cap rocks positively correlated to the oil and gas reserves. The development of high-quality evaporite cap rock is highly favorable for oil and gas preservation. We identified four hydrocarbon generation models, and that the major source rocks have undergone a long period of burial and thermal evolution and are characterized by early and long periods of hydrocarbon generation. These giant oil and gas fields have diverse types of reservoirs and are mainly distributed in paleo-uplifts, slope zones, and platform margin reef-shoal bodies. The main factors that control their formation and distribution were identified, enabling the prediction of new favorable areas for oil and gas exploration.

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Section: Source Rocksmentioning

confidence: 99%

Formation and distribution characteristics of Proterozoic–Lower Paleozoic marine giant oil and gas fields worldwide

et al. 2017

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“…Due to the geological factors, such as the structural movement at the timing of reservoir formation, the reservoir conditions, and the later tectonic evolution, the proportions of the concentrated or dispersed liquid hydrocarbons are difficult to determine [52,53]. Wang et al [54] provided two methods to discuss the occurrence of the dispersed liquid hydrocarbons both in Sichuan Basin and in Tarim Basin.…”

Section: Petroleum Outside the Source Rocksmentioning

confidence: 99%

“…Large amount of thermally cracked gas can become an important gas source kitchen for shale gas, which is formed in the mature/overmature stages by dispersed liquid hydrocarbons inside the sources [53,62]. Before 2000, many experts thought that there is no exploration potential in the area where the source rocks are highly mature to overmature, because the hydrocarbon generation is thought to have been exhausted at those maturities [20].…”

Section: Potential Of Cracked Gas From Residual Oil In Sourcementioning

confidence: 99%

New Insight into the Kinetics of Deep Liquid Hydrocarbon Cracking and Its Significance

Zhao

Zhang

et al. 2017

Geofluids

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The deep marine natural gas accumulations in China are mainly derived from the cracking of liquid hydrocarbons with different occurrence states. Besides accumulated oil in reservoir, the dispersed liquid hydrocarbon in and outside source also is important source for cracking gas generation or relayed gas generation in deep formations. In this study, nonisothermal gold tube pyrolysis and numerical calculations as well as geochemical analysis were conducted to ascertain the expulsion efficiency of source rocks and the kinetics for oil cracking. By determination of light liquid hydrocarbons and numerical calculations, it is concluded that the residual bitumen or hydrocarbons within source rocks can occupy about 50 wt.% of total oil generated at oil generation peak. This implies that considerable amounts of natural gas can be derived from residual hydrocarbon cracking and contribute significantly to the accumulation of shale gas. Based on pyrolysis experiments and kinetic calculations, we established a model for the cracking of oil and its different components. In addition, a quantitative gas generation model was also established to address the contribution of the cracking of residual oil and expulsed oil for natural gas accumulations in deep formations. These models may provide us with guidance for gas resource evaluation and future gas exploration in deep formations.

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“…The maturity of the Lower Paleozoic shale in south China is generally rather high, but it varies significantly in different regions (Nie et al 2009). The Lower Cambrian and Lower Silurian shales have EqR o values of, respectively, 2.7 %-6.2 % and 1.9 %-3.8 % in the whole Yangtze region (Cheng and Xiao 2013), and 2.5 %-3.5 % and 2.4 %-3.2 % in the Sichuan Basin (Wang et al 2009a;Zou et al 2014). Shale generally has a quite low porosity when it has evolved to the dry gas stage (R o [ 2.0 %) (Wang et al 2013a), but its reservoir properties still change with further increasing maturity (Chen and Xiao 2014).…”

Section: Geological Characteristics Of the Lower Paleozoic Shalementioning

confidence: 99%

“…In the Sichuan Basin, the strong uplifting led to the erosion of the Lower Cretaceous-Jurassic strata after the late Cretaceous, with a total erosion thickness of 2000-5000 m Wang and Xiao 2010;Zou et al 2014), and, as a result, a portion of the Lower Paleozoic shale has a current burial depth suitable for shale gas exploitation (Li et al 2013a). In the southeastern area of the Sichuan Basin, the shale system with a strong overpressure is far away from faults, eroded surfaces, and basin edges, with a pressure coefficient generally greater than 1.5 and up to 2.25 (e.g., well Y101) , which implies that simple uplifting/folding can basically retain the fluid pressure coefficient of a shale system.…”

Section: Uplifting/folding and Loss Of Shale Gasmentioning

confidence: 99%

Main controlling factors and enrichment area evaluation of shale gas of the Lower Paleozoic marine strata in south China

et al. 2015

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The Lower Paleozoic shale in south China has a very high maturity and experienced strong tectonic deformation. This character is quite different from the North America shale and has inhibited the shale gas evaluation and exploration in this area. The present paper reports a comprehensive investigation of maturity, reservoir properties, fluid pressure, gas content, preservation conditions, and other relevant aspects of the Lower Paleozoic shale from the Sichuan Basin and its surrounding areas. It is found that within the main maturity range (2.5 % \ EqR o \ 3.5 %) of the shale, its porosity develops well, having a positive correlation with the TOC content, and its gas content is controlled mainly by the preservation conditions related to the tectonic deformation, but shale with a super high maturity (EqR o [ 3.5 %) is considered a high risk for shale gas exploration. Taking the southern area of the Sichuan Basin and the southeastern area of Chongqing as examples of uplifted/folded and faulted/folded areas, respectively, geological models of shale gas content and loss were proposed. For the uplifted/folded area with a simple tectonic deformation, the shale system (with a depth [ 2000 m) has largely retained overpressure during uplifting without a great loss of gas, and an industrial shale gas potential is generally possible. However, for the faulted/folded area with a strong tectonic deformation, the sealing condition of the shale system was usually destroyed to a certain degree with a great loss of free gas, which decreased the pressure coefficient and resulted in a low production capacity. It is predicted that the deeply buried shale ([3000 m) has a greater gas potential and will become the focus for further exploration and development in most of the south China region (outside the Sichuan Basin).

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Formation, distribution, resource potential, and discovery of Sinian–Cambrian giant gas field, Sichuan Basin, SW China

Cited by 330 publications

References 7 publications

Formation and distribution characteristics of Proterozoic–Lower Paleozoic marine giant oil and gas fields worldwide

Formation and distribution characteristics of Proterozoic–Lower Paleozoic marine giant oil and gas fields worldwide

New Insight into the Kinetics of Deep Liquid Hydrocarbon Cracking and Its Significance

Main controlling factors and enrichment area evaluation of shale gas of the Lower Paleozoic marine strata in south China

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