Study of the blocking mechanism in gravel packing based on CFD-DEM

Gravel packing sand control (GPSC), as the optimization of mechanical sand control technology, is widely used in the deep water completion and sand control of loose sandstone heavy oil reservoirs and highly argillaceous. To explore the blocking mechanism of GPSC, the influence of its structural parameters on the blocking of GPSC is investigated. This paper establishes a particle element model based on computational fluid dynamics-discrete element method coupling using the discrete element method and establishes a fluid flow model combined with computational fluid dynamics to realize their full coupling solution. And sand control experiments were carried out using a micro visual sand control simulation device to verify the blocking model. The blocking mechanism is analyzed from the microscopic point of view, and then, the influence of sand control structure parameters on the blocking in GPSC design is evaluated. The results show the following: (1) the blocking process of GPSC can be divided into three stages: an initial stage, sand accumulation stage, and equilibrium stage. (2) There are two main types of gravel packing blockage. The first type of blocking is blocking on the surface of the gravel layer. Sand particles on the surface of gravel layer mainly exist in the form of large particle size blocking gravel pores and sand particles bridging each other. The second type of blockage is the blockage inside the gravel layer. Sand particles mainly exist in the form of internal mud cakes and adsorption on gravels inside the gravel layer. (3) To ensure the sand control performance of the gravel layer, the gravel layer thickness is designed between 23 and 28 mm. The displacement or pressure of the on -site packing pump should be increased to ensure that the gravel layer packing solidity ranges between 59% and 62%. In the design of GPSC, it should be ensured that the median particle size of gravel is 5-6 times the median particle size of sand. This study provides an effective technical reference for the design of gravel structural parameters in on -site gravel packing completion sand control. (c) 2023 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.