Evaluation of the shale gas potential of the lower Silurian Longmaxi Formation in northwest Hunan Province, China

Abstract Commercial gas production has been achieved in China's marine shale of the Silurian Longmaxi formation in the eastern Sichuan area, and experience for developing shale gas in complex structural areas has been gathered. A set of Longmaxi Formation shales deposited in the northwestern Hunan area has close relationship with the eastern Sichuan Longmaxi shale on both depositional environment and tectonic evolution. Therefore, it is important to undertake an integrated evaluation of the Longmaxi formation shale in the northwestern Hunan area. This work combined field investigations and the laboratory measurements using outcrop samples to study the petrology, geochemistry, reservoir and adsorption characteristics of the Longmaxi shale in the northwestern Hunan area. The geological settings and reservoir properties were compared with those of the eastern Sichuan Longmaxi shale using publically available data. The results show that the hydrocarbon generation ability, organic matter maturity, sealing capacity and reservoir stimulation effectiveness of the Longmaxi Formation shale in the northwestern Hunan area are comparable to those in the eastern Sichuan area. The Longmaxi shale in the northwestern Hunan area therefore shows early signs of development potential, and the drilling of exploration wells is thus warranted to further evaluate its gas content and other in-situ reservoir properties for possible shale gas development in the near future.

[1]  E. L. Couch.  Calculation of Paleosalinities from Boron and Clay Mineral Data , 1971 .

[2]  A. Foscolos,et al.  Mineralogical and Geochemical Transformation of Clays During Burial-Diagenesis (Catagenesis): Relation to Oil Generation , 1979 .

[3]  Liang Wei,et al.  Tide-dominated Deltaic Deposits in Lungamachi Formation,Longshan-Yongshun Regions,Northwestern Hunan:The initial sedimentary responses to outset of “Xuefeng uplift” , 2014 .

[4]  D. Jarvie,et al.  Unconventional shale-gas systems: The Mississippian Barnett Shale of north-central Texas as one model for thermogenic shale-gas assessment , 2007 .

[5]  Zhang Bilong.  The Folding Time of the Eastern Sichuan Jura-type Fold Belt:Evidence from Unconformity , 2009 .

[6]  Liu Shao-feng.  Rock mechanical characteristics of the multi-layer detachment fault system and their controls on the structural deformation style of the Sichuan-Chongqing-Hunan-Hubei thin-skinned belt, South China , 2008 .

[7]  M. D. Rudnicki,et al.  Organic matter–hosted pore system, Marcellus Formation (Devonian), Pennsylvania , 2013 .

[8]  C. H. Bruce.  Smectite Dehydration--Its Relation to Structural Development and Hydrocarbon Accumulation in Northern Gulf of Mexico Basin , 1984 .

[9]  Tongwei Zhang,et al.  Effect of organic-matter type and thermal maturity on methane adsorption in shale-gas systems , 2012 .

[10]  Hanrong Zhang,et al.  Formation and enrichment mode of Jiaoshiba shale gas field, Sichuan Basin , 2014 .

[11]  Li Zhi-ming,et al.  Distribution of Black Shale in the Wufeng-Longmaxi Formations (Ordovician-Silurian),South China: Major Controlling Factors and Implications , 2007 .

[12]  B. Velde,et al.  The Origin of Clay Minerals in Soils and Weathered Rocks , 2008 .

[13]  Tongwei Zhang,et al.  Experimental investigation of main controls to methane adsorption in clay-rich rocks , 2012 .

[14]  Wang Shufan.  Biogenic Silica of Organic-Rich Shale in Sichuan Basin and Its Significance for Shale Gas , 2014 .

[15]  Bernhard M. Krooss,et al.  Shale Gas Potential of the Major Marine Shale Formations in the Upper Yangtze Platform, South China, Part III: Mineralogical, Lithofacial, Petrophysical, and Rock Mechanical Properties , 2014 .

[16]  Stephen C. Ruppel,et al.  Mississippian Barnett Shale: Lithofacies and depositional setting of a deep-water shale-gas succession in the Fort Worth Basin, Texas , 2007 .

[17]  R. Rickman,et al.  A Practical Use of Shale Petrophysics for Stimulation Design Optimization: All Shale Plays Are Not Clones of the Barnett Shale , 2008 .

[18]  Jinliang Huang,et al.  Geochemistry of the extremely high thermal maturity Longmaxi shale gas, southern Sichuan Basin , 2014 .

[19]  Wang Jia.  Shale gas exploration prospect of Lower Paleozoic in southeastern Sichuan and western Hubei-eastern Chongqing areas,China , 2011 .

[20]  Xiangliang Zeng,et al.  Characteristics of the Shale Gas Reservoir Rocks in the Lower Silurian Longmaxi Formation, East Sichuan Basin, China , 2013 .

[21]  R. Loucks,et al.  Morphology, Genesis, and Distribution of Nanometer-Scale Pores in Siliceous Mudstones of the Mississippian Barnett Shale , 2009 .

[22]  Fang Yuan-fang.  Mesozoic Intra-Continental Progressive Deformation in Western Hunan-Hubei-Eastern Sichuan Provinces of China:Evidence from Apatite Fission Track and Balanced Cross-Section , 2010 .

[23]  Zhiming Hu,et al.  Impact of temperature on the isothermal adsorption/desorption of shale gas , 2013 .

[24]  Sun Meng-di.  Clay Minerals of Black Shale and Their Effects on Physical Properties of Shale Gas Reservoirs in the Southeast of Chongqing:A Case Study from Lujiao Outcrop Section in Pengshui,Chongqing , 2012 .

[25]  Luke D. Connell,et al.  Reservoir simulation of free and adsorbed gas production from shale , 2015 .

[26]  J. Curtis.  Fractured shale-gas systems , 2002 .

[27]  Xia Kai-hua.  The burial history and models for hydrocarbon generation and evolution in the marine strata in southern China , 2007 .

[28]  Chun Liu,et al.  The characterization and quantitative analysis of nanopores in unconventional gas reservoirs utilizing FESEM–FIB and image processing: An example from the lower Silurian Longmaxi Shale, upper Yangtze region, China , 2014 .

[29]  Wei Guo,et al.  2D and 3D nanopore characterization of gas shale in Longmaxi formation based on FIB-SEM , 2016 .

[30]  Lie-hui Zhang,et al.  Lower limits of evaluation parameters for the lower Paleozoic Longmaxi shale gas in southern Sichuan Province , 2013, Science China Earth Sciences.

[31]  Wang Maozhe.  Pore Characteristics and Methane Adsorption of Clay Minerals in Shale Gas Reservoir , 2015 .

[32]  A. Foscolos,et al.  Diagenesis of Clay Minerals from Lower Cretaceous Shales of North Eastern British Columbia , 1974 .

[33]  Feiyu Wang,et al.  Evolution of overmature marine shale porosity and implication to the free gas volume , 2013 .

[34]  Daniel M. Jarvie,et al.  Mississippian Barnett Shale, Fort Worth basin, north-central Texas: Gas-shale play with multi–trillion cubic foot potential , 2005 .

[35]  M. Curtis,et al.  Structural Characterization of Gas Shales on the Micro- and Nano-Scales , 2010 .

[36]  Sw Petroleum.  Tectonic Control of the Silurian Reef Distribution and Development on Upper Yangtze Platform , 1996 .

[37]  Zhang Chang-jun.  Comparison of Silurian Longmaxi Formation shale of Sichuan Basin in China and Carboniferous Barnett Formation shale of Fort Worth Basin in United States , 2011 .

[38]  Stephen C. Ruppel,et al.  Spectrum of pore types and networks in mudrocks and a descriptive classification for matrix-related mudrock pores , 2012 .

[39]  Luke D. Connell,et al.  Experimental study and modelling of methane adsorption and diffusion in shale , 2014 .

[40]  I. Lerche,et al.  Determination of Paleoheat Flux from Vitrinite Reflectance Data , 1984 .

[41]  C. Boreham,et al.  Shale gas potential of the major marine shale formations in the Upper Yangtze Platform, South China, Part II: Methane sorption capacity , 2014 .

[42]  Xuan Feng,et al.  A shale rock physics model for analysis of brittleness index, mineralogy and porosity in the Barnett Shale , 2013 .

[43]  L. Connell,et al.  An experimental investigation of diffusivity and porosity anisotropy of a Chinese gas shale , 2015 .

[44]  Yan Jin,et al.  A criterion for identifying hydraulic fractures crossing natural fractures in 3D space , 2014 .

[45]  Liu Yang,et al.  Pore structure of the graptolite-derived OM in the Longmaxi Shale, southeastern Upper Yangtze Region, China , 2016 .

[46]  S. Yao,et al.  New understandings of Ni–Mo mineralization in early Cambrian black shales of South China: Constraints from variations in organic matter in metallic and non-metallic intervals , 2014 .

[47]  Luke D. Connell,et al.  Experimental study of anisotropic gas permeability and its relationship with fracture structure of Longmaxi Shales, Sichuan Basin, China , 2016 .

[48]  Shuangfang Lu,et al.  Organoporosity Evaluation of Shale: A Case Study of the Lower Silurian Longmaxi Shale in Southeast Chongqing, China , 2014, TheScientificWorldJournal.

[49]  H. Harder.  Boron content of sediments as a tool in facies analysis , 1970 .