三维大变化尺度缝洞型碳酸盐岩油藏流体流动规律及流-固耦合综合模型研究

Complex flow mechanisms in fracture-cavity reservoirs have not been incorporated into current commercial simulators for such reseroirs. The impact of coupled flow of different flow behaviors on reservoir development has been ignored, which more uncertainties to field development plan and production forecast. Existing study on flow mechanisms are based on micro etching and 2D plate (0.1m thick) experiments, which are not representative of the special structures and multiple flow mechanisms in the fractures and cavities. Based on similarity theory, this project is to study two-phase flow of oil and water in such reservoirs and figure out the impact of different factors, e.g. fracture-cavity structure (distribution, dimenssion, size and connectivity), reservoir oil and water distribution, and flooding conditions (pattern, injection timing and injection/production rates), etc., on the flow mechanism through experiments of large-scale, changing-scale and 3D oil-water flow. Meanwhile, multiple flow behaviors, such as non-Darcy flow, tubing flow, fracture plate flow, inner cavity convection flow and various inter-media coupled flows are studied to develop a integrated flow model. This project has important significance theoretically and practically to help improve the development planning of such reservoirs.

现有商品化裂缝性油藏数值模拟器未考虑缝洞性油藏复杂渗流特征，忽略了多种流动特征耦合流动对油藏开发的影响，导致该类油藏开发方案设计和开发指标预测存在不可靠性。现有流动特征研究方法以微观刻蚀及二维平板（0.1米厚）实验为基础，无法反映缝洞内部特殊结构，不能准确揭示缝洞内的多种流动特征。本项目以缝洞性油藏油水两相流动规律为研究对象，根据相似原理，进行大尺寸、变尺度，三维油水流动实验，揭示缝洞结构（分布、形态、尺度、连通关系）、地下油水分布、水油注采条件（注采位置、注采时机、注采强度）等多个因素之间的关系以及对流动规律的影响。并以此为基础考虑变尺度流动通道中非达西流、管流、裂缝平板流、溶洞内部对流及介质间各种流动耦合等多种流动特征，建立缝洞型油藏多种流动特征耦合、流-固耦合非线性流动综合模型。研究成果对于深入研究缝洞性油藏开采机理和开发动态，提高缝洞性油藏开发开发设计水平具有重要的理论和应用价值。

本项目综合运用地球化学、渗流力学、油藏工程等多学科知识，采用多种分析、实验手段，针对缝洞性油藏油水两相流动规律开展研究，主要取得以下进展：（1）根据相似原理，进行大尺寸、变尺度，三维油水流动实验，揭示缝洞结构、地下油水分布、水油注采条件等多个因素之间的关系以及对流动规律的影响。（2）建立了一套研究缝洞型碳酸盐岩油藏油水运动规律的变尺度室内物理模拟的体系及方法。（3）考虑变尺度流动通道中非达西流、管流、裂缝平板流、溶洞内部对流及介质间各种流动耦合等多种流动特征，建立缝洞型油藏多种流动特征耦合、流-固耦合非线性流动综合模型。