Sweet spot classification evaluation of tight conglomerate reservoir in Mahu Sag and its engineering application

QIN Jianhua1 ZHANG Jing1 JIANG Qingping1 FENG Yueli1 ZHAO Yiqing1 ZHU Jian1 LU Zhiyuan1 WU Shunwei1

(1.Research Institute of Petroleum Exploration & Development, PetroChina Xinjiang Oilfield Company)

【Abstract】With the expansion of global oil and gas exploration toward deep, subtle, and unconventional reservoirs, new breakthroughs have been made in oil and gas exploration in China. The Mahu tight conglomerate reservoirs in the Junggar Basin, Xinjiang are rich in oil resources and have great potential for large-scale construction. However, the factors that affect the oil flow capacity in the reservoir are complex and diverse. Also, there are a number of challenges during the development. For example, the reservoir heterogeneity is strong; the determination and classified evaluation of “sweet spot” are difficult; the difference of horizontal principal stress between the two directions is large; the formation and extension mechanism of hydraulic fractures is unclear; the cost is high; the geological conditions are complex. Guided by geology-engineering integration, combining the geological characteristics of the study area with the production practice, we have established the classified evaluation standard of “sweet spots” for this type of reservoirs. By the method of volume fracturing with intensive segments, stereoscopic development technologies and tests of “long horizontal sections, intensive segments, small well spacing, large well clusters and industrialized production” have been explored, forming a set of technical systems for efficient development of tight conglomerate reservoirs and achieving good results. The improvements of accuracy in description of “sweet spots” and 3D geological models have significantly increased the efficiency of drilling and completion engineering. The average number of adjustment times of horizontal section trajectories decreased from 5 m to 2 m and the penetration rate of the oil layer reached up to more than 90%. Moreover, the average cluster spacing in Ma-131 well block decreased from 67 m to 35 m, and the average cumulative production increased by 37.5% in 300 days.

【Keywords】 tight conglomerate; sweet spot classification; small well spacing; intensive segment; stereoscopic development;

【DOI】

【Funds】 National Science and Technology Major Project (2017ZX05070-001) Scientific Research and Technology Development Project of PetroChina (KT2018-13-02)

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    References

    [1] Zhu Weiyao, Yue Ming, Liu Yunfeng, Liu Kai, Song Zhiyong. Research progress on tight oil exploration in china [J]. Chinese Journal of Engineering, 2019, 41 (9): 1103–1114 (in Chinese).

    [2] Fan Jianming, Chen Xiaodong, Lei Zhengdong, Gao Wubin, Wang Chong. Characteristics of natural and hydraulic fractures in the tight oil reservoir in Ordos Basin and its implication to field development [J]. Journal of China University of Petroleum: Edition of Natural Science, 2019, 43 (3): 98–106 (in Chinese).

    [3] Liu Zhongqun. Geological characteristics and development strategies of fractured tight oil reservoirs in Jinghe oilfield [J]. Journal of Southwest Petroleum University: Science & Technology Edition, 2019, 41 (2): 23–32 (in Chinese).

    [4] Li Yang. Opportunities and challenges for Sinopec to develop tight oil reservoirs [J]. Petroleum Drilling Techniques, 2015, 43 (5): 1–6 (in Chinese).

    [5] Wang Lichen, Tian Hongliang, Zhen Jian, Lei Qihong. Present conditions of tight oil in North America and analysis of economic performance [J]. Oil Forum, 2014, 33 (5): 56–61 (in Chinese).

    [6] Yin Guoqing, Zhang Hui, Wang Haiying, Wang Zhimin, Liu Xinyu. Application of geology engineering integration in efficient exploration in structure KS24 [J]. Xinjiang Petroleum Geology, 2019, 40 (4): 486–792 (in Chinese).

    [7] Li Guoxin, Wang Feng, Pi Xuejun, Liu He. Optimized application of geology-engineering integration data of unconventional oil and gas reservoirs [J]. China Petroleum Exploration, 2019, 24 (2): 147–152 (in Chinese).

    [8] Sun Hongliang, Liang Yu, Wang Jing, Qian Feng, Cui Yanli, Luo Jun, et al. Precise management based on geology engineering integration for exploration of complex oil reservoirs in Tuha oilfield [J]. China Petroleum Exploration, 2019, 24 (2): 196–202 (in Chinese).

    [9] Xie Jun, Zhang Haomiao, She Chaoyi, Li Qirong, Fan Yu, Yang Yang. Practice of geology-engineering integration in Changning state shale gas demonstration area [J]. China Petroleum Exploration, 2017, 22 (1): 21–28 (in Chinese).

    [10] Chang Shaoying, Zhu Yongfeng, Cao Peng, Dai Chuanrui, Liu Weibo, Yan Xiaofang. Application of geology-engineering integration in high-efficiency remaining oil potential tapping and its results: a case study on YM32 dolomite oil reservoirs in Tarim Basin [J]. China Petroleum Exploration, 2017, 22 (1): 46–52 (in Chinese).

    [11] Dai Yong, Chen Kaiming, Peng Jingyun, Li Li, Han Yonggang, Du Gang. Exploration and practice of the integrated operation mode of “Scientific Research + Production” [J]. Oil Forum, 2015, 34 (2): 10–15 (in Chinese).

    [12] Warpinski N R. Hydraulic Fracturing in tight, fissured media[J]. Journal of Petroleum Technology, 1991, 43 (2): 146–209.

    [13] Murillo G G, Salguero J. Conventional fracturing vs. complex fracturing network in tight turbidite oil deposits in Mexico [R]. SPE 180999-MS, 2016.

    [14] Zou Caineng, Tao Shizhen, Bai Bin, Yang Zhi, Zhu Rukai, Hou Lianhua, et al. Differences and relations between unconventional and conventional oil and gas [J]. China Petroleum Exploration, 2015, 20 (1): 1–16 (in Chinese).

    [15] Lei Qun, Yang Lifeng, Duan Yaoyao, Weng Dingwei, Wang Xin, Guan Baoshan, et al. The “fracture-controlled reserves” based stimulation technology for unconventional oil and gas reservoirs [J]. Petroleum Exploration and Development, 2018, 45 (4): 719–726 (in Chinese).

    [16] Dou Hongen, Ma Shiying. Lessons learned from oil production of tight oil reservoirs in Bakken play [J]. Oil Drilling & Production Technology, 2012, 34 (2): 120–124 (in Chinese).

    [17] Chen Jianjun, Weng Dingwei. CNPC’s progress in horizontal well fracturing technologies for unconventional reservoirs [J]. Natural Gas Industry, 2017, 37 (9): 79–84 (in Chinese).

    [18] Xu Jiangwen, Li Jianmin, Wu Yuanyue, Ding Kun, Jiang Hong. Exploration and practice of volume fracturing technology in the horizontal well of Mahu tight conglomerate reservoirs [J]. China Petroleum Exploration, 2019, 24 (2): 241–249 (in Chinese).

    [19] Li Jianmin, Wu Baocheng, Zhao Haiyan, Cheng Ning, Huang Jialing. Adaptability of horizontal well volume fracturing to tight conglomerate reservoirs in Mahu[J]. China Petroleum Exploration, 2019, 24 (2): 250–259 (in Chinese).

    [20] Tang Shuheng, Zhu Baocun, Yan Zhifeng. Effect of in-situ stress on the development of hydraulic fracturing fractures in coalbed gas wells [J]. Journal of China Coal Society, 2011, 36 (4): 65–69 (in Chinese).

    [21] Zhou Jian, Chen Mian, Jin Yan, Zhang Guangqing. Experimental study on the mechanism of hydraulic fracture propagation in multi-fractured reservoirs [J]. Journal of China University of Petroleum: Edition of Natural Science, 2008 (4): 51–54, 59 (in Chinese).

    [22] Zhang Zike. Study on the effect of natural fractures on hydraulic fracture under high-stress conditions [D]. Beijing: China University of Petroleum (Beijing), 2017 (in Chinese).

    [23] Huang Xiaoqing, Wang Jianjun, Du Yue, Li Lin, Zhang Zhuo. Discussion on development mode of smaller well spacing and tridimensional development in the YS108 block, Zhaotong National Shale Gas Demonstration Area [J]. Natural Gas Geoscience, 2019, 30 (4): 557–565 (in Chinese).

    [24] Zhu Haiyan. Study on adaptability evaluation of polymer flooding at small well spacing in conglomerate reservoir [D]. Beijing: China University of Petroleum (Beijing), 2018 (in Chinese).

    [25] Liu Chao. Research on the test scheme for the development of the small well spacing in the Huang 39 well area of Ji’an oil field [D]. Chengdu: Southwest Petroleum University, 2014 (in Chinese).

    [26] Qin Jianhua, Ding Yi, Yang Xu, Chi Jianping, Pan Qianying, Lu Peiyi, et al. Pilot test of close spacing development in lower Wuerhe reservoir of district No. 8 of Karamay field [J]. XinJiang Petroleum Geology, 2009, 30 (6): 725–727 (in Chinese).

    [27] Yan Cunzhang, Li Xiusheng, Chang Yuwen, Yu Lijun, Shi Jianzi. Development of a low permeability reservoir with closely spaced wells [J]. Petroleum Exploration and Development, 2005, 32 (1): 105–108 (in Chinese).

    [28] Wang Tianju, Chen Zan, Wang Rui, Wu Chunfang, Xu Hongzhi, Hao Zhiwei. A new method for cluster spacing optimization during volumetric fracturing in tight sandstone oil reservoirs [J]. XinJiang Petroleum Geology, 2019, 40 (3): 351–356.

    [29] Heng Feng, Wang Gang, Liu Bo, Chu Fangdong, Zhang Yanbin, Feng Chao. Hydraulic fracturing with different cluster spacing based on microseismic monitoring [J]. Oil Geophysical Prospecting, 2018, 53 (S2): 137–142 (in Chinese).

    [30] Ren Lan, Lin Ran, Zhao Jinzhou, Wu Leize. Cluster spacing optimal design for staged fracturing in horizontal shale gas wells based on optimal SRV [J]. Natural Gas Industry, 2017, 37 (4): 69–79 (in Chinese).

    [31] Zhao Jinzhou, Xu Wenjun, Li Yongming, Cai Kunchi, Xu Miao. A new method for cluster spacing optimization of multicluster staged fracturing in horizontal wells of low-permeability oil and gas reservoirs [J]. Natural Gas Industry, 2016, 36 (10): 63–69 (in Chinese).

    [32] Huang Jing. Optimization of spatial fracturing cluster spacing in horizontal wells of tight oil reservoirs in Lucaogou [D]. Chengdu: Southwest Petroleum University, 2016 (in Chinese).

This Article

ISSN:1672-7703

CN: 11-5215/TE

Vol 25, No. 02, Pages 110-119

March 2020

Downloads:21

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Article Outline

Abstract

  • 0 Introduction
  • 1 Overview of the study area
  • 2 Major challenges in development of Mahu tight conglomerate reservoirs
  • 3 Research on key technologies for increasing production and efficiency
  • 4 Conclusions
  • References