裂缝交叉角度对缝网导流能力的影响: 以“ 卜” 形结构为例.

Regarding the cross fracture structure of “卜” type as the basic unit of the fracture network to discuss the fracture network conductivity. The conductivity of shale slabs with the intersection angles of primary and secondary fracture of 30°, 60°, 90°, 120° and 150° were carried out, using a rubber sleeve with the outer circle and the inner square configuration as fracture conductivity chamber. And the fracture volume equivalent theory was used to calculate the network conductivity. The experimental results show that the secondary fracture contribute a lot to improve the fracture network conductivity regardless of the intersection angles of primary and secondary fracture and the concentration of proppant placement in the secondary fracture. And increasing the proppant placement concentration is beneficial to maintain in the fracture network conductivity stable and efficient under high closure stress. However, the larger the fluid confluence angle is, the greater the fluid energy loss caused by the fluid collision and other effects, which shows that the “卜” type fracture network conductivity decreases with the increasing the intersection angles of primary and secondary fracture. Therefore, fully considering the intersection angle of the fluid confluence has a significantly important role in accurately evaluating the fracture network conductivity. [ABSTRACT FROM AUTHOR]