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Petrophysical properties of deep Longmaxi Formation shales in the southern Sichuan Basin, SW China
XU Zhonghua,ZHENG Majia,LIU Zhonghua,DENG Jixin,LI Xizhe,GUO Wei,LI Jing,WANG Nan,ZHANG Xiaowei,GUO Xiaolong
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Petrophysical properties of deep Longmaxi Formation shales in the southern Sichuan Basin, SW China
),LI Xizhe6,GUO Wei6,LI Jing2,WANG Nan6,ZHANG Xiaowei6,GUO Xiaolong6Deep shale layer in the Lower Silurian Longmaxi Formation, southern Sichuan Basin is the major replacement target of shale gas exploration in China. However, the prediction of “sweet-spots” in deep shale gas reservoirs lacks physical basis due to the short of systematic experimental research on the physical properties of the deep shale. Based on petrological, acoustic and hardness measurements, variation law and control factors of dynamic and static elastic properties of the deep shale samples are investigated. The study results show that the deep shale samples are similar to the middle-shallow shale in terms of mineral composition and pore type. Geochemical characteristics of organic-rich shale samples (TOC > 2%) indicate that these shale samples have a framework of microcrystalline quartz grains; the intergranular pores in these shale samples are between rigid quartz grains and have mechanical property of hard pore. The lean-organic shale samples (TOC < 2%), with quartz primarily coming from terrigenous debris, feature plastic clay mineral particles as the support frame in rock texture. Intergranular pores in these samples are between clay particles, and show features of soft pores in mechanical property. The difference in microtexture of the deep shale samples results in an asymmetrical inverted V-type change in velocity with quartz content, and the organic-rich shale samples have a smaller variation rate in velocity-porosity and velocity-organic matter content. Also due to the difference in microtexture, the organic-rich shale and organic-lean shale can be clearly discriminated in the cross plots of P-wave impedance versus Poisson’s ratio as well as elasticity modulus versus Poisson’s ratio. The shale samples with quartz mainly coming from biogenic silica show higher hardness and brittleness, while the shale samples with quartz from terrigenous debris have hardness and brittleness less affected by quartz content. The study results can provide a basis for well-logging interpretation and “sweet spot” prediction of Longmaxi Formation shale gas reservoirs.
southern Sichuan Basin / Silurian / deep Longmaxi Formation shale / rock physical properties / elasticity velocity {{custom_keyword}} /
| [1] | JIA Chengzao, ZHENG Min, ZHANG Yongfeng. Unconventional hydrocarbon resources in China and the prospect of exploration and development. Petroleum Exploration and Development, 2012,39(2):129-136. |
| [2] | JIN Zhijun, HU Zongquan, GAO Bo, et al. Controlling factors on the enrichment and high productivity of shale gas in the Wufeng-Longmaxi Formations, southeastern Sichuan Basin. Earth Science Frontiers, 2016,23(1):1-10. |
| [3] | MA Yongsheng, FENG Jianhui, MOU Zehui, et al. The potential and exploring progress of unconventional hydrocarbon resources in SINOPEC. Engineering Sciences, 2012,14(6):22-30. |
| [4] | LIU Zhenwu, SA Liming, YANG Xiao, et al. Needs of geophysical technologies for shale gas exploration. Oil Geophysical Prospecting, 2011,46(5):810-818. |
| [5] | VERNIK L, NUR A. Ultrasonic and anisotropy of hydrocarbon source rocks. Geophysics, 1992,57(5):727-735. |
| [6] | SONDERGELD C H, RAI C S, MARGESSON R W, et al. Ultrasonic measurement of anisotropy on the Kimmeridge Shale. Calgary: 70th Annual International Meeting, Society of Exploration Geophysicists, 2000. |
| [7] | SONDERGELD C H, RAI C S. Elastic anisotropy of shales. The Leading Edge, 2011,30(3):324-331. |
| [8] | DEWHURST D N, SIGGINS A F, SAROUT J, et al. Geomechanical and ultrasonic characterization of a Norwegian sea shale. Geophysics, 2011,76(6):WA101-WA111. |
| [9] | DENG Jixin, WANG Huan, ZHOU Hao, et al. Microtexture, seismic rock physical properties and modeling of Longmaxi Formation shale. Chinese Journal of Geophysics, 2015,58(6):2123-2136. |
| [10] | DENG Jixin, TANG Zhengyuan, LI Yue, et al. The influence of the diagenetic process on seismic. Chinese Journal of Geophysics, 2018,61(2):659-672. |
| [11] | HORNBY B E, SCHWARTZ L M, HUDSON J A. Anisotropic effective-medium modeling of the elastic properties of shales. Geophysics, 1994,59(10):1570-1583. |
| [12] | VERNIK L, MILOVAC J. Rock physics of organic shales. The Leading Edge, 2011,30(3):324-331. |
| [13] | CARCIONE JOSé M, AVSETH P. Rock-physics templates for clay-rich source rocks. Geophysics, 2015,80(5):D481-D500. |
| [14] | GUO Z Q, LI X Y, LIU C, et al. A shale rock physics model for analysis of brittleness index, mineralogy and porosity in the Barnett Shale. Journal of Geophysics and Engineering, 2013,10(1):1-10. |
| [15] | ZHANG F, LI X Y, QIAN Z. Estimation of anisotropy parameters for shale based on an improved rock physics model. Journal of Geophysics and Engineering, 2017,14(2):143-158. |
| [16] | HICKEY J J, BO H. Lithofacies summary of the Mississippian Barnett Shale, Mitchell 2 T. P. Sims well, Wise County, Texas. AAPG Bulletin, 2007,91(4):437-443. |
| [17] | ABOUELRESH M O, SLATT R M. Lithofacies and sequence stratigraphy of the Barnett Shale in east-central Fort Worth Basin, Texas. AAPG Bulletin, 2012,96(1):1-12. |
| [18] | WEDEPOHL K H. Environmental influences on the chemical composition of shales and clays. Physics and Chemistry of the Earth, 1971,8(2):307-331. |
| [19] | YAMAMOTO K. Geochemical characteristics and depositional environments of cherts and associated rocks in the Franciscan and Shimanto Terranes. Sedimentary Geology, 1987,52(1):65-108. |
| [20] | ROWE H D, LOUCKS R G, RUPPEL S C, et al. Mississippian Barnett Formation, Fort Worth Basin, Texas: Bulk geochemical inferences and Mo-TOC constraints on the severity of hydrographic restriction. Chemical Geology, 2008,257(1/2):16-25. |
| [21] | ROSS D J, BUSTIN R M. Investigating the use of sedimentary geochemical proxies for paleoenvironment interpretation of thermally mature organic-rich strata: Examples from the Devonian-Mississippian shales, Western Canadian Sedimentary Basin. Chemical Geology, 2009,260(1/2):1-19. |
| [22] | AVSETH P, MUKERJI T, MAVKO G, et al. Rock-physics diagnostics of depositional texture, diagenetic alterations, and reservoir heterogeneity in high porosity siliciclastic sediments and rocks: A review of selected models and suggested work flows. Geophysics, 2010,75(5):31-47. |
| [23] | MAVKO G, MUKERJI T, DVORKIN J. The rock physics handbook second edition. Cambridge: Cambridge University Press, 2009. |
| [24] | LI Q H, CHEN M, JIN Y, et al. Indoor evaluation method for shale brittleness and improvement. Chinese Journal of Rock Mechanics and Engineering (in Chinese), 2012,31(8):1680-1686. |
| [25] | RICKMAN R, MULLEN M, ERIK PETREL E, et al. A practical use of shale petrophysics for stimulation design optimization: All shale plays are not clones of the Barnett shale. SPE 115258, 2008. |
| [26] | WANG F P, GALE J F W. Screening criteria for shale-gas systems. Transactions of the Gulf Coast Association of Geological Societies, 2009,59:779-793. |
| [27] | PRASAD M, MBA K, MCEVOY T E. Maturity and impedance analysis of organic-rich shales. SPE Reservoir Evaluation and Engineering, 2011,14(5):533-543. |
| [28] | ELIYAHU M. Mechanical properties of organic matter in shales mapped at the nanometer scale. Marine and Petroleum Geology, 2015,59:294-304. |
| [29] | JARVIE D M, HILL R J, RUBLE T E, et al. Unconventional shale-gas systems: The Mississippian Barnett Shale of north-central Texas as one model for thermogenic shale-gas assessment. AAPG Bulletin, 2007,91(4):475-499. |
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