长江大学Fucheng Deng研究小组近日取得一项新成果。他们进行了基于CFD-DEM的砾石充填堵塞机理研究。2023年12月20日出版的《颗粒学报》发表了这项成果。

砾石充填防砂(GPSC)作为机械防砂技术的优化，在松散砂岩稠油油藏和高泥化稠油油藏的深水完井防砂中得到了广泛的应用。为了探究GPSC的阻断机制，该团队研究了其结构参数对GPSC阻断的影响。

研究人员使用离散元法，建立了基于CFD-DEM耦合的颗粒元模型，并结合计算流体力学建立了流体流动模型，实现了两者的完全耦合求解。此外研究人员还利用微型视觉防沙模拟装置进行了防沙实验，验证了该模型的有效性。这项研究从微观角度分析了挡砂机理，评价了GPSC防砂结构参数对挡砂效果的影响。

研究结果表明：(1)GPSC的阻塞过程可分为初始阶段、堆积阶段和平衡阶段三个阶段；(2)砾石充填堵塞主要有两种类型：第一类堵塞是砾石层表面的堵塞，砾石层表面的砂粒主要以大颗粒堵塞砾石孔隙和砂粒相互桥接的形式存在；第二类堵塞是砾石层内的堵塞，砂粒主要以内部泥饼的形式存在，并吸附在砾石层内部的砾石上；(3)为保证砾石层防砂性能，砾石层厚度设计在23 ~ 28mm之间，应增加现场充填泵的排量或压力，保证砾石层充填固体度在59% ~ 62%之间；在GPSC的设计中，应保证砾石的中位粒径为砂石中位粒径的5 ~ 6倍。

该研究为现场砾石充填完井防砂中砾石结构参数的设计提供了有效的技术参考。

附：英文原文

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

Author: anonymous

Issue&Volume: 2023/12/20

Abstract: 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 CFD-DEM 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 to 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% to 62%. In the design of GPSC, it should be ensured that the median particle size of gravel is 5 to 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.

DOI: 10.1016/j.partic.2023.12.005

Source: https://www.sciencedirect.com/science/article/abs/pii/S167420012300322X