Development practice of continental shale oil in Jimsar Sag in the Junggar Basin

GAO Yang1 YE Yiping2 HE Jixiang1 QIAN Genbao2 QIN Jianhua1 LI Yingyan1

(1.Exploration and Production Research Academy, PetroChina Xinjiang Oilfield Company)
(2.PetroChina Xinjiang Oilfield Company)
【Knowledge Link】fracturing fluid

【Abstract】The Permian Lucaogou Formation in the Jimsar Sag, Junggar Basin, Xinjiang is rich in continental shale oil resources, with an estimated resource more than 15.8 × 108 t. In order to realize the effective development of shale oil, based on the detailed analysis of geological characteristics, engineering technologies, production characteristics and laws of continental shale oil in the Lucaogou Formation, and combined with the development practice, we have obtained the following achievements and understandings in recent years: (1) The source rocks of the Lucaogou shale oil in the Jimsar Sag are from the continental shale of saline lacustrine fine-grained deposit, which are high-quality source rocks with large thickness and characterized by integrated sources and reservoirs. Oil is accumulated in situ in the shale intervals, and in the “sweet spot” intervals, hydrocarbons were mainly supplied from adjacent source rocks with self-generation as auxiliary. All these characteristics indicated the typical continental shale oil. (2) It is clear that the free porosity and free oil reserve abundance in the fracture-controlled areas created by volume fracturing from horizontal wells constitute the basis of high production for the shale oil. (3) With the increase in buried depth, the difference of horizontal two-direction stress increases, and the fracture complexity decreases, which is the main reason for the low production of some horizontal wells with good oil-bearing property in the “upper sweet spot interval”. (4) The oil viscosity is the key control factor of the production from horizontal wells in the “lower sweet spot interval”. (5) The penetration length of high-quality “sweet spots” and the proppant volume per meter during hydraulic fracturing are the key engineering factors for the high production from shale oil horizontal wells in the Jimsar Sag. (6) Due to the imbibition and replacement between the fracturing fluid and the shale oil in the matrix pores, the production can be improved by proper soaking after fracturing. (7) Due to the limitation of hydraulic fracture length, the appropriate well spacing should not be larger than 200 m. Through continuous research and development practice, shale oil development has obtained good results. The maximum annual production of a single horizontal well has been more than 1.3 × 104 m3. Since 2019, it has basically entered the stage of large-scale trial production, which accumulated rich experiences for the industrial development of continental shale oil in China.

【Keywords】 Jimsar Sag; shale oil; development practice; geological characteristics; well spacing;

【DOI】

【Funds】 Major Science and Technology projects of CNPC “Research and application of key technologies for exploration and development of shale oil with medium-high maturity in continental facies” (2019E-26) “Research and application of key technologies for exploration and development in Xinjiang Oilfield and Tuha Oilfield” (2017E-04)

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    References

    [1] JIA Lu, ZHANG Jianhua. The impact of U.S. shale revolution on global oil & gas and petrochemical industry [J]. Petroleum & Petrochemical Today, 2017, 25 (7): 7–13 (in Chinese).

    [2] ZHANG Linye, LI Juyuan, LI Zheng, ZHANG Jingong, ZHU Rifang, BAO Youshu. Advances in shale oil/gas research in North America and considerations on exploration for continental shale oil/gas in China [J]. Advances in Earth Science, 2014, 29 (6): 700–711 (in Chinese).

    [3] LI Denghua, LIU Zhuoya, ZHANG Guosheng, ZHENG Zhihong, JIA Jun, GAO Nuan, et al. Comparison and revelation of tight oil accumulation conditions, distribution characteristics and development status between China and U.S. [J]. Natural Gas Geoscience, 2017, 28 (7): 1126–1138 (in Chinese).

    [4] LI Shizhen, LIU Weibin, WANG Dandan, ZHANG Wenhao, LIN Yanhua. Continental shale oil geological conditions of China and the United States [J]. Geological Review, 2017, 63 (S1): 39–40 (in Chinese).

    [5] LIN Senhu, ZOU Caineng, YUAN Xuanjun, YANG zhi. Status quo of tight oil exploitation in the United States and its implication [J]. Lithologic Reservoirs, 2011, 23 (4): 25–30 (in Chinese).

    [6] ZOU Caineng, ZHU Ruikai, BAI Bin, YANG Zhi, WU Songtao. First discovery of nano-pore throat in oil and gas reservoir in China and its scientific value [J]. Acta Petrologica Sinica, 2011, 27 (6): 1857–1864 (in Chinese).

    [7] JIA Chengzao, ZHENG Min, ZHANG Yongfeng. Unconventional hydrocarbon resources in China and the prospect of exploration and development [J]. Petroleum Exploration and Development, 2012, 39 (2): 129–136 (in Chinese).

    [8] KANG Yuzhu. Significant exploration progress and resource potential of unconventional oil and gas in China [J]. Oil Forum, 2018 (4): 1–6 (in Chinese).

    [9] DU Jinhu, HU Suyun, PANG Zhenglian, LIN Senghu, HOU Lianhua, ZHU Rukai. The types, potentials and prospects of continental shale oil in China [J]. China Petroleum Exploration, 2019, 24 (5): 560–568 (in Chinese).

    [10] FU Jinhua, NIU Xiaobing, DAN Weidong, FENG Shengbin, LIANG Xiaowei, XIN Honggang, et al. The geological characteristics and the progress on exploration and development of shale oil in Chang 7 Member of Mesozoic Yanchang Formation, Ordos Basin [J]. China Petroleum Exploration, 2019, 24 (5): 601–613 (in Chinese).

    [11] LI Zhongxing, QU Xuefeng, LIU Wantao, LEI Qihong, SUNun Hualing, HE Youan. Development modes of Triassic Yanchang formation Chang7 member tight oil in Ordos basin, NW China [J]. Petroleum Exploration and Development, 2015, 2 (1): 217–221 (in Chinese).

    [12] YAN Lin, YUAN Dawei, CHEN Fuli, GAO Yang, WANG Shaojun, CHENG Fucheng, et al. A study on differentiated oil-bearing controlling factors and distribution patterns of continental tight oil reservoir [J]. Xinjiang Petroleum Geology, 2019, 40 (3): 262–268 (in Chinese).

    [13] YANG Hua, LI Shixiang, LIU Xianyang. Characteristics and resource prospects of tight oil and shale oil in Ordos Basin [J]. Acta Petrolei Sinica, 2013, 34 (1): 1–11 (in Chinese).

    [14] SONG Mingshui. Practice and current status of shale oil exploration in Jiyang Depression [J]. Petroleum Geology and Recovery Efficiency, 2019, 26 (1): 1–12 (in Chinese).

    [15] ZHAO Xianzheng, ZHOU Lihong, ZHAO Min, WANG Wenge, GUAN Quansheng. Breakthrough and practice of industrial development on continental shale oil: a case study on Kong-2 Member in Cangdong sag, Bohai Bay Basin [J]. China Petroleum Exploration, 2019, 24 (5): 589–600 (in Chinese).

    [16] LIANG Shijun, LUO Quansheng, WANG Rui, CHEN Xuan, YANG Bin, MA Qiang, et al. Geological characteristics and exploration practice of unconventional Permian oil resources in the Santanghu Basin [J]. China Petroleum Exploration, 2019, 24 (5): 624–635 (in Chinese).

    [17] HUO Jin, HE Jixiang, GAO Yang, DONG Yan, XU Dongsheng, LI Yingyan. Difficulties and countermeasures of shale oil development in Lucaogou formation of Jimsar sag [J]. Xinjiang Petroleum Geology, 2019, 40 (4): 379–388 (in Chinese).

    [18] LIU Yishan, DONG Xiaohu, YAN Lin, CHEN Fuli, GAO Yanling, CHEN Zhangxing, et al. Quantitative characterization of pore structure of Lucaogou formation in Jimsar sag [J]. Xinjiang Petroleum Geology, 2019, 40 (3): 284–289 (in Chinese).

    [19] LI Longlong, ZHANG Yang, CAO Chunjie, JIA Baoquan, YANG Xinghai, XIAO Bin, et al. Effect evaluation of Chang 7 tight oil huff and puff in block AP of Hujianshan oilfield [J]. Petrochemical Industry Application, 2017, 36 (11): 66–68 (in Chinese).

    [20] WU Zhongbao, ZENG Qian, LI Jin, WANG Lu. New effective energy-supplement development method of water flood huff and puff for the oil reservoir with stimulated reservoir volume fracturing [J]. Petroleum Geology and Recovery Efficiency, 2017, 24 (5): 78–83.(in Chinese).

    [21] FAN Yu, ZHOU Xiaojin, ZENG Bo, SONG Yi, ZHOU Nayun, CHEN Juan. Application of intensivestaged fracturing technology in deep shale gas Well Zi2 [J]. Xinjiang Petroleum Geology, 2019, 40 (2): 223–227 (in Chinese).

This Article

ISSN:1672-7703

CN: 11-5215/TE

Vol 25, No. 02, Pages 133-141

March 2020

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Abstract

  • 0 Introduction
  • 1 Main geological characteristics of continental shale oil in the Jimsar Sag
  • 2 Effect of shale oil development
  • 3 Understandings of shale oil in the development stage
  • 4 Conclusions
  • References