Petroleum Science >2024, Issue1: - DOI: https://doi.org/10.1016/j.petsci.2023.09.022
The effects of various factors on spontaneous imbibition in tight oil reservoirs Open Access
文章信息
作者:Cheng Liu, Tian-Ru Wang, Qing You, Yue-Chun Du, Guang Zhao, Cai-Li Dai
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引用方式:Cheng Liu, Tian-Ru Wang, Qing You, Yue-Chun Du, Guang Zhao, Cai-Li Dai, The effects of various factors on spontaneous imbibition in tight oil reservoirs, Petroleum Science, Volume 21, Issue 1, 2024, Pages 315-326, https://doi.org/10.1016/j.petsci.2023.09.022.
文章摘要
Abstract: Slickwater fracturing fluids have gained widespread application in the development of tight oil reservoirs. After the fracturing process, the active components present in slickwater can directly induce spontaneous imbibition within the reservoir. Several variables influence the eventual recovery rate within this procedure, including slickwater composition, formation temperature, degree of reservoir fracture development, and the reservoir characteristics. Nonetheless, the underlying mechanisms governing these influences remain relatively understudied. In this investigation, using the Chang-7 block of the Changqing Oilfield as the study site, we employ EM-30 slickwater fracturing fluid to explore the effects of the drag-reducing agent concentration, imbibition temperature, core permeability, and core fracture development on spontaneous imbibition. An elevated drag-reducing agent concentration is observed to diminish the degree of medium and small pore utilization. Furthermore, higher temperatures and an augmented permeability enhance the fluid flow properties, thereby contributing to an increased utilization rate across all pore sizes. Reduced fracture development results in a lower fluid utilization across diverse pore types. This study deepens our understanding of the pivotal factors affecting spontaneous imbibition in tight reservoirs following fracturing. The findings act as theoretical, technical, and scientific foundations for optimizing fracturing strategies in tight oil reservoir transformations.
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Keywords: Tight oil reservoir; Spontaneous imbibition; Nuclear magnetic resonance; Slickwater fracturing fluid; Fluid utilization degree