Stimulation Capability of Low-Medium Maturity Shale Oil Reservoir During In-Situ Conversion

doi:10.7657/XJPG20230414

Abstract

Abstract:

In China, the abundant low-medium maturity shale oil resources present a huge potential for in-situ conversion. To evaluate the stimulation capability of low-medium maturity shale oil reservoir during in-situ conversion, in-situ heating experiments were conducted on the typical low-medium maturity shales from Chang 7 member of Yanchang formation in Ordos basin and Lucaogou formation of Jimsar sag in Junggar basin. By using techniques such as nuclear magnetic resonance testing, vertical optical microscopy observation, computerized tomography scanning, and pulse decay gas permeability measurement, the dynamic changes in nano-scale pores, thermal fractures, porosity and permeability under high-temperature and high-pressure conditions during in-situ conversion were monitored in a real-time manner. The kerogen pyrolysis-induced fractures and the hydrocarbon generation pressurization effect are key factors for significantly improving the microstructure and reservoir properties. Once the temperature exceeds the threshold (400°C), the extension, density, complexity and connectivity of fractures within the shale significantly increase due to kerogen pyrolysis and thermal expansion of hydrocarbons. Secondary pores with diameters ranging from 2 to 50 nm become dominant in the pore structure. Under in-situ stress, the porosities of the two types of shale can be increased by 3.65 and 2.73 times, respectively, while the permeability can be increased by 624.09 and 418.37 times, respectively. Permeability is more stress-sensitive in the high-temperature stage than in the low-temperature stage. Shale reservoir with lower in-situ stress and higher kerogen content exhibit higher stimulation capability and higher thermal fracturing and thermal permeability enhancement capabilities during in-situ conversion.

Key words: low-medium maturity shale oil, in-situ conversion, reservoir stimulation, kerogen pyrolysis, hydrocarbon generation pressurization, stress sensitivity, thermal fracturing, thermal permeability enhancement

CLC Number:

TE348

WEI Zijian, SHENG Jiaping, ZHANG Xiao. Stimulation Capability of Low-Medium Maturity Shale Oil Reservoir During In-Situ Conversion[J]. Xinjiang Petroleum Geology, 2023, 44(4): 485-496.

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References 34

[1]	SHENG James. Enhanced oil recovery in shale and tight reservoirs[M]. Houston: Gulf Professional Publishing, 2019.
[2]	胡素云, 赵文智, 侯连华, 等. 中国陆相页岩油发展潜力与技术对策[J]. 石油勘探与开发, 2020, 47(4):819-828. doi: 10.11698/PED.2020.04.19
	HU Suyun, ZHAO Wenzhi, HOU Lianhua, et al. Development potential and technical strategy of continental shale oil in China[J]. Petroleum Exploration and Development, 2020, 47(4):819-828.
[3]	杜金虎, 胡素云, 庞正炼, 等. 中国陆相页岩油类型、潜力及前景[J]. 中国石油勘探, 2019, 24(5):560-568. doi: 10.3969/j.issn.1672-7703.2019.05.003
	DU Jinhu, HU Suyun, PANG Zhenglian, et al. The types,potentials and prospects of continental shale oil in China[J]. China Petroleum Exploration, 2019, 24(5):560-568. doi: 10.3969/j.issn.1672-7703.2019.05.003
[4]	赵文智, 胡素云, 侯连华. 页岩油地下原位转化的内涵与战略地位[J]. 石油勘探与开发, 2018, 45(4):537-545. doi: 10.11698/PED.2018.04.01
	ZHAO Wenzhi, HU Suyun, HOU Lianhua. Connotation and strategic role of in-situ conversion processing of shale oil underground in the onshore China[J]. Petroleum Exploration and Development, 2018, 45(4):537-545.
[5]	陈国辉, 蒋恕, 李醇, 等. 加热过程中页岩储层改质效果研究进展[J]. 石油与天然气地质, 2022, 43(2):286-296.
	CHEN Guohui, JIANG Shu, LI Chun, et al. Progress in shale reservoir upgrading through in-situ heating[J]. Oil & Gas Geology, 2022, 43(2):286-296.
[6]	ALPAK F O, VINK J C, GAO G, et al. Techniques for effective simulation,optimization,and uncertainty quantification of the in-situ upgrading process[J]. Journal of Unconventional Oil and Gas Resources, 2013, 3:1-14.
[7]	SAIF T, LIN Q, SINGH K, et al. Dynamic imaging of oil shale pyrolysis using synchrotron X‐ray microtomography[J]. Geophysical Research Letters, 2016, 43(13):6 799-6 807. doi: 10.1002/2016GL069279
[8]	BAI Fengtian, SUN Youhong, LIU Yumin, et al. Evaluation of the porous structure of Huadian oil shale during pyrolysis using multiple approaches[J]. Fuel, 2017, 187:1-8. doi: 10.1016/j.fuel.2016.09.012
[9]	常思阳. 松辽盆地油页岩加热过程储集物性特征研究[D]. 长春: 吉林大学, 2017.
	CHANG Siyang. Reservoir characteristics of oil shale during heating in Songliao basin[D]. Changchun: Jilin University, 2017.
[10]	刘志军. 温度作用下油页岩孔隙结构及渗透特征演化规律研究[D]. 太原: 太原理工大学, 2018.
	LIU Zhijun. Temperature dependence of evolution of pore structure and permeability characteristics of oil shale[D]. Taiyuan: Taiyuan University of Technology, 2018.
[11]	刘志军, 杨栋, 胡耀青, 等. 油页岩原位热解孔隙结构演化的低温氮吸附分析[J]. 西安科技大学学报, 2018, 38(5):737-742.
	LIU Zhijun, YANG Dong, HU Yaoqing, et al. Low temperature nitrogen adsorption analysis of pore structure evolution in in-situ pyrolysis of oil shale[J]. Journal of Xi’an University of Science and Technology, 2018, 38(5):737-742.
[12]	LIU Zhijun, YANG Dong, HU Yaoqing, et al. Influence of in situ pyrolysis on the evolution of pore structure of oil shale[J]. Energies, 2018, 11(4):755. doi: 10.3390/en11040755
[13]	耿毅德, 梁卫国, 刘剑, 等. 不同温压条件下油页岩孔裂隙结构演化试验研究[J]. 岩石力学与工程学报, 2018, 37(11):2 510-2 519.
	GENG Yide, LIANG Weiguo, LIU Jian, et al. Experimental study on the variation of pore and fracture structure of oil shale under different temperatures and pressures[J]. Chinese Journal of Rock Mechanics and Engineering, 2018, 37(11):2 510-2 519.
[14]	GENG Yide, LIANG Weiguo, LIU Jian, et al. Evolution of pore and fracture structure of oil shale under high temperature and high pressure[J]. Energy & Fuels, 2017, 31(10):10 404-10 413. doi: 10.1021/acs.energyfuels.7b01071
[15]	董付科, 杨栋, 冯子军. 高温三轴应力下吉木萨尔油页岩渗透率演化规律[J]. 煤炭技术, 2017, 36(8):165-166.
	DONG Fuke, YANG Dong, FENG Zijun. Permeability evolution of Jimsar oil shale under high temperature and triaxial stresses[J]. Coal Technology, 2017, 36(8):165-166.
[16]	DONG Fuke, FENG Zong, YANG Dong, et al. Permeability evolution of pyrolytically-fractured oil shale under in situ conditions[J]. Energies, 2018, 11(11):3 033. doi: 10.3390/en11113033
[17]	王国营, 杨栋, 康志勤. 高温三轴应力作用下油页岩的渗透特征各向异性演化规律实验研究[J]. 岩石力学与工程学报, 2020, 39(6):1 129-1 141.
	WANG Guoying, YANG Dong, KANG Zhiqin. Experimental study on anisotropic permeability of oil shale under high temperature and triaxial stress[J]. Chinese Journal of Rock Mechanics and Engineering, 2020, 39(6):1 129-1 141.
[18]	WANG Guoying, YANG Dong, ZHAO Yangsheng, et al. Experimental investigation on anisotropic permeability and its relationship with anisotropic thermal cracking of oil shale under high temperature and triaxial stress[J]. Applied Thermal Engineering, 2019, 146:718-725. doi: 10.1016/j.applthermaleng.2018.10.005
[19]	韦自健, 盛家平, 杨凌风. 耐高温岩芯夹持器以及岩芯温度追踪加热系统[P]. 中国, CN112153763B. 2021.07.02.
	WEI Zijian, SHENG Jiaping, YANG Lingfeng. High temperature resistant core holder and temperature tracking heating system[P]. China, CN112153763B. 2021.07.02.
[20]	LIU Dayong, LI Hengchao, ZHANG Can, et al. Experimental investigation of pore development of the Chang 7 member shale in the Ordos basin under semi-closed high-pressure pyrolysis[J]. Marine and Petroleum Geology, 2019, 99:17-26. doi: 10.1016/j.marpetgeo.2018.08.014
[21]	WU Songtao, YANG Zhi, ZHAI Xiufen, et al. An experimental study of organic matter,minerals and porosity evolution in shales within high-temperature and high-pressure constraints[J]. Marine and Petroleum Geology, 2019, 102:377-390. doi: 10.1016/j.marpetgeo.2018.12.014
[22]	DING Xiujian, QU Jiangxiu, IMIN A, et al. Organic matter origin and accumulation in tuffaceous shale of the Lower Permian Lucaogou formation,Jimsar sag[J]. Journal of Petroleum Science and Engineering, 2019, 179:696-706. doi: 10.1016/j.petrol.2019.05.004
[23]	袁伟. 鄂尔多斯盆地延长组长7段富有机质页岩形成机理[D]. 北京: 中国石油大学(北京), 2018.
	YUAN Wei. Formation mechanism of the organic-rich shales in the 7th member of Yanchang formation,Ordos basin[D]. Beijing: China University of Petroleum(Beijing), 2018.
[24]	曲长胜. 吉木萨尔凹陷二叠系芦草沟组富有机质混积岩特征及其形成环境[D]. 山东青岛: 中国石油大学(华东), 2017.
	QU Changsheng. Characteristics and depositional environment of organic-rich mixed sedimentary rocks in Permian Lucaogou formation,Jimusaer sag[D]. Qingdao,Shandong: China University of Petroleum (East China), 2017.
[25]	梁成钢, 谢建勇, 陈依伟, 等. 吉木萨尔凹陷芦草沟组页岩储集层裂缝成因及耦合关系[J]. 新疆石油地质, 2021, 42(5):521-528.
	LIANG Chenggang, XIE Jianyong, CHEN Yiwei, et al. Genesis and coupling relationship of fractures in shale reservoir of Lucaogou formation in Jimsar sag,Junggar basin[J]. Xinjiang Petroleum Geology, 2021, 42(5):521-528.
[26]	KALJUVEE T, KEELMANN M, TRIKKEL A, et al. Thermooxidative decomposition of oil shales[J]. Journal of thermal analysis and calorimetry, 2011, 105(2):395-403. doi: 10.1007/s10973-010-1033-0
[27]	卢婷, 王鸣川, 马文礼, 等. 考虑多重应力敏感效应的页岩气藏压裂水平井试井模型[J]. 新疆石油地质, 2021, 42(6):741-748.
	LU Ting, WANG Mingchuan, MA Wenli, et al. Fractured horizontal well test model for shale gas reservoirs with considering multiple stress sensitive factors[J]. Xinjiang Petroleum Geology, 2021, 42(6):741-748.
[28]	KANG Yili, CHEN Mingjun, CHEN Zhanxin, et al. Investigation of formation heat treatment to enhance the multiscale gas transport ability of shale[J]. Journal of Natural Gas Science and Engineering, 2016, 35:265-275. doi: 10.1016/j.jngse.2016.08.058
[29]	MAHADEVAN J, SHARMA M M, YORTSOS Y C. Evaporative cleanup of water blocks in gas wells[J]. SPE Journal, 2007, 12(2):209-216. doi: 10.2118/94215-PA
[30]	SING K S W. Reporting physisorption data for gas/solid systems with special reference to the determination of surface area and porosity (Recommendations 1984)[J]. Pure and Applied Chemistry, 1985, 57(4):603-619. doi: 10.1351/pac198557040603
[31]	GAVRILENKO P, GUEGUEN Y. Pressure dependence of permeability:A model for cracked rocks[J]. Geophysical Journal International, 1989, 98(1):159-172. doi: 10.1111/gji.1989.98.issue-1
[32]	WEI Zijian, SHENG J J. Study of thermally-induced enhancement in nanopores,microcracks,porosity and permeability of rocks from different ultra-low permeability reservoirs[J]. Journal of Petroleum Science and Engineering, 2022, 209:109896. doi: 10.1016/j.petrol.2021.109896
[33]	YANG D, ELSWORTH D, KANG Z Q, et al. Experiments on permeability evolution with temperature of oil shale[C]. In 46th US Rock Mechanics/Geomechanics Symposium. OnePetro, 2012.
[34]	LI Qingyou, HAN Xiangxin, LIU Qingqing, et al. Thermal decomposition of Huadian oil shale. Part 1. Critical Organic Intermediates[J]. Fuel, 2014, 121:109-116. doi: 10.1016/j.fuel.2013.12.046