YANG Zhaozhong, GAO Chenxuan, LI Xiaogang, et al. Laboratory study on reducing fracturing friction of shale reservoir by proppant slug during pad[J]. Petroleum Reservoir Evaluation and Development, 2020, 10(1): 77-83. DOI: 10.13809/j.cnki.cn32-1825/te.2020.01.012.
Laboratory study on reducing fracturing friction of shale reservoir by proppant slug during pad
In order to solve the problem that the injection pressure of shale reservoir in Fuling area is too high in the early stage of hydraulic fracturing
researches on the resistance reduction based on proppant slug technology was carried out. By using the previous self-developed jet device and target
a set of physical simulation method for reducing fracture resistance in near well by grinding perforation with proppant slug was established and the orthogonal experiment was carried out. For the on-site needs
fore-tail pressure drop and average pressure drop rate are established to characterize the experimental results
and then analyzed accordingly. The results show that the influence of various factors on the resistance reduction effect from large to small is in the following orders: sand ratio
particle size
number of slugs(grinding time) and proppant type. The effect of reducing resistance of quartz sand is better than that of ceramsite. Drag reduction increases with the thickening of proppant particle size and the increase of sand ratio
and decreases at first and then increases with the prolongation of grinding time. Based on the results of orthogonal experiment
the optimal operating parameters of quartz sand with particle size of 40/70 mesh
sand ratio of 9 % and grinding time of 9 min are selected. On this condition
the optimal friction reduction effect of pressure drop rate of 0.439 MPa/min and head-tail pressure drop of 1.04 MPa are obtained. The experimental study provides a certain reference for the construction design of hydraulic fracturing of shale reservoir.