Multi-fracture flow balanced distribution law in horizontal well sections considering perforation friction
In the process of staged multi-cluster fracturing of horizontal wells,the inter-cluster stress shadow will cause the difference of multi-fracture fluid injection.The production logging data of shale gas reservoir shows that more than 40％of perforation clusters have no contribution to oil and gas production.In order to reveal the mechanism of multi-fracture nonuniform propagation,a finite element model of multi-fracture competitive propagation considering the fluid-solid coupling of porous media was established,the wellbore flow model was established and the fracturing fluid flow pressure drop was simply represented,the pipe flow unit and fluid connection unit were designed and introduced to effectively simulate the dynamic distribution of flow between the wellbore and the perforation hole,and the law of the perforation friction on the distribution ratio of multi-fracture fluid injection was studied.The results show that when the perforation friction increases to a specific threshold,the proportion of multi-fracture flow distribution will change from inter-cluster stress shadow to perforation friction dominance.Reasonably arranging low perforation density and the number of perforation can effectively increase perforation friction and promote balanced propagation of multi-fractures;Using this model to optimize the perforation plan of southwest horizontal well X,when the cluster spacing is 15 m,the perforation diameter is 0.015 m,and the total number of perforation is reduced from 50 to 32,the average fluid inflow of a single cluster is increased by 0.125 m3/min,and the difference coefficient of fluid inflow for each cluster is 3.9％;When the perforations are distributed unevenly,the average fluid inflow of a single cluster increases by 0.101 m3/min,and the difference coefficient of fluid inflow of each cluster is decreased to 4.1％.This study provides a theoretical method and reference basis for multi-fracture uniform propagation in horizontal wells.
shale gas reservoir staged multi-clusterdynamic flow distributionperforation frictionbalanced fracture propagation
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