Fundamentals of sand control fluid flows

在一个碳氢化合物枯竭的时代，资源开发不可避免地将越来越多地集中在不那么固结和困难的油藏上。在过去的15-20年里，“防砂”已成为石油和天然气行业使用的完井服务组合中日益增长和重要的一部分。为了防止储层固体物质造成生产堵塞，并以机械方式部分支撑周围的储层，通常用分级固体颗粒(通常是沙子或特殊设计的陶瓷)填充油井：即所谓的砾石填充。拟议的项目侧重于一些需要了解的基本物理过程，以便能够可靠地设计和执行裸眼完井。该项目分为两个子项目。(子项目I)。首先，我们打算研究标准的水砾石充填技术。在水平井目前的砾石充填完井中，这种类型的充填物占了很大比例。我们将重新检查现有的过程力学模型，这些模型主要集中在稳定流动上，改进浆料局部行为的物理模型，并开发瞬时过程模型。主要目标是量化目前的业务，并了解造成当前限制和故障的实际原因，以适应新的业务情况(分项目二)。其次，我们打算研究另一种路径配置的粘性泥浆，在这种配置中，流体被转移到较小的次级管道(分流管)，通过这些管道可以绕过堵塞，以确保均匀的砾石堆积。粘性泥浆包括各种非牛顿流体，它们具有更高的粘度，有助于颗粒的传输，但具有摩擦损失，可通过粘弹性湍流减阻来缓解。我们打算朝两个方向努力：(A)进行高速流动回路测试，以表征这些流体的井下流动条件并量化减阻机理；(B)结合数值模拟开发能够预测和优化这些流动的流变学模型。

In an era of hydrocarbon depletion, it is inevitable that resource development will focus increasingly on less consolidated and difficult reservoirs. In the past 15-20 years "sand control" has become a growing and significant part of the portfolio of well completion services used in the oil and gas industry. To prevent reservoir solids from causing production blockages and to partially support the surrounding reservoir mechanically, it is common to pack the well with graded solid particles (usually sand, or specially designed ceramics): so called gravel-packing. The proposed project focuses on some of the fundamental physical processes that need to be understood in order that open hole completions can be reliably designed and executed. The project is organized in 2 sub-projects.(Sub-project I). First, we intend to study standard water gravel-packing techniques. This type of packing accounts for a large percentage of current gravel-packed completions in horizontal wells. We will re-examine current mechanical models for the process, which focus largely on steady flows, improve the physical models for the local behaviour of the slurry and develop a transient process model. The main objective is to quantify current operations and understand the physical reasons for current limitations and failures in a way that is adaptable to new operational scenarios.(Sub-project II). Second, we intend to study viscous slurries in alternate path configurations where fluids are diverted to smaller, secondary ducts (shunt tubes) through which blockages may be bypassed to ensure a uniform gravel pack. Viscous slurries include various non-Newtonian fluids with higher viscosities to aid in particle transport but with frictional losses which are mitigated via viscoelastic turbulent drag-reduction. We intend to work in 2 directions: (a) running high speed flow loop tests to characterize the down-hole flow conditions of these fluids and quantify drag reduction mechanisms; (b) developing rheological models in conjunction with numerical simulation to be able to predict and optimize these flows.