Study on method of sweet spot interval identification of tight gas reservoir in horizontal well

doi:10.3969/j.issn.1672-7703.2021.03.011

Abstract

Abstract: Horizontal well drilling combining with multi-staged fracturing is proved to be an important method for tight gas reservoir development. However, due to the strong heterogeneity of tight gas reservoir and the great difference in production contribution of each stage,accurately identifying the sweet spot interval of horizontal section and optimizing fracturing scale has become the key process to improve production capacity. The microseismic vector scanning monitoring was conducted for 57 stages in six horizontal wells, and 72 effective fractured intervals were identified. The correlation analysis of these intervals and the related parameters of wireline logging and mud logging data shows that total hydrocarbon and the rate of penetration (ROP) have the best correlation with those fractured intervals. Therefore,formula for calculating the parameter Ktr of sweet spot interval (easily fractured position) is established by using total hydrocarbon and ROP.The application result shows significantly more microseismic events in stages with abnormal Ktr than other stages in Well S-13H, indicating more initiated fractures, and three sweet spot intervals contribute more than 90% of the total production. In addition, production has a good relationship with the sweet spot interval identified by Ktr value in another five horizontal wells without microseismic monitoring data. It is verified that the Ktr method can accurately identify the sweet spot interval in horizontal section, which has guiding significance for selecting the fracturing stage and technology optimization of horizontal wells.

Key words: fracturing sweet spot, horizontal section, staged fracturing, total hydrocarbon, ROP

CLC Number:

TE357

Liu Zixiong, Li Xiaonan, Wang Jinwei, Liu Rumin, Wang Tao, Wang Yizhu, Yan Zhidong, Li Xinfa. Study on method of sweet spot interval identification of tight gas reservoir in horizontal well[J]. China Petroleum Exploration, 2021, 26(3): 117-125.

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