油页岩
断裂(地质)
地质学
电导率
页岩油
石油工程
岩土工程
导水率
土壤科学
化学
物理化学
古生物学
土壤水分
作者
Yingfeng Meng,Zenglin Wang,Liaoyuan Zhang,Chu He,Ronghua Wen,Liang Zhang
出处
期刊:Lithosphere
[GeoScienceWorld]
日期:2021-08-04
卷期号:2021 (Special 1)
被引量:3
摘要
Abstract The productivity of shale oil reservoirs is mainly determined by the hydraulic fractured reservoir volume. The branch fractures with low sand laying concentration are the main channels connecting the shale matrix and the main fractures. Maintaining the branch fracture conductivity is significant to the production of shale oil. In this study, a series of shale branch fracture conductivity and soaking experiments were conducted using a core flooding device and a small reactor, and the influences of different factors on the fracture conductivity were evaluated. The results show that when the sand laying concentration in fractures is less than 3 kg/m2, the branch fractures present a significant stress sensitivity. Particularly when the sand laying concentration is less than 1 kg/m2, and the closure pressure is greater than 15 MPa, there will be a risk of proppant embedded and fracture closed. The antiswelling agent has an inhibitory effect on the shale swelling. When the concentration of the antiswelling agent in the gel-breaking fluid is 2%, the swelling factor of shale powder is only 1.84%. Comparatively, the 0.5% of the antiswelling agent has a poor effect which can cause the shale rock to crack when the effective stress decreases. It can cause the fracture conductivity to decline by 70-90% when the gel-breaking fluid flows back associated with the shale oil. The probability of core breaking and proppant embedding will increase. The frequent shut-in and rapid open-flow for production can accelerate the damage of fracture conductivity. It is necessary to optimize the fracturing fluid and the open flow scheme to prevent the rapid decline of production in shale oil reservoirs.
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