China Petroleum Exploration ›› 2021, Vol. 26 ›› Issue (2): 21-32.DOI: 10.3969/j.issn.1672-7703.2021.02.003

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Major breakthrough of shale oil and gas in Well Taiye 1 in Bashansi Syncline in the Sichuan Basin and its significance#br#

Hu Dongfeng, Wei Zhihong, Liu Ruobing, Wei Xiangfeng, Liu Zhujiang, Chen feiran   

  1. Sinopec Exploration Company
  • Online:2021-03-15 Published:2021-03-15

Abstract: In January 2021, Well Taiye 1, the first shale oil and gas exploratory well targeting at the Jurassic Lianggaoshan Formation,
was deployed in the Bashansi Syncline in the northern part of Fuling area in the Sichuan Basin, and obtained oil and gas flow rate of 9.8 m3/d and 7.5×104 m3/d respectively, by multi-staged fracturing and testing of the horizontal section, indicating a major breakthrough in lacustrine shale oil and gas exploration. Based on drilling results of Well Taiye 1, hydrocarbon accumulation
conditions and enrichment rules of lacustrine shale oil and gas in the Jurassic Lianggaoshan Formation were analyzed in detail.
Results indicate that the producing layer in Well Taiye 1 is organic rich shale in the 2nd member of Lianggaoshan Formation
(Liang 2 member) developed in semi-deep lake facies. In this layer, the 4th sub-layer is about 25.20 m in thickness, with the average TOC greater than 1.5%, organic matter type predominated by Type II, Ro ranging from 1.01%?1.41%, gas content of 1.81 m3/t, and an average porosity of 3.52%. Inorganic pores are dominant (clay mineral interlayer pores, intergranular pores, intragranular pores, etc.), and organic pores are developed locally, with pore diameter mainly of mesopores (2?50 nm) and macropores(>50 nm). Compared with other thin layers, the 4th sub-layer has the largest continuous thickness, the highest TOC, porosity, and gas content, representing a self-generation and self-storage shale oil and gas reservoir of “pure shale type”. The high-quality semi-deep lacustrine shale are widely developed in the northern part of Fuling area, which is favorable for shale oil and gas enrichment.The area with good preservation conditions, high formation pressure, and well-developed micro-fractures are conducive to the high production of shale oil and gas. Key technology of volume fracturing with characteristics of “few stages and multi cluster + temporary plugging and diversion + high pumping rate + medium to coarse sand proppants and high intensity sand injection” has been researched and developed, which enables effective stimulation on lacustrine shale. In conclusion, breakthrough of Well Taiye 1 is of great significance to the commercial development of lacustrine shale oil and gas in China.

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