低渗透油藏数值模拟技术研究

低渗透油藏数值模拟技术研究

摘要

随着现代石油工业的发展，低渗透油田的开发愈来愈为人们所重视。与中、高渗油藏相比较，低渗透油藏具有以下明显渗流特征：流体渗流不遵循达西定律，渗流中存在启动压力梯度，并且应力敏感性影响不可忽略。

本文在广泛调研的基础上，综合考虑启动压力梯度和应力敏感性，对低渗透油田的数值模拟方法进行研究。主要考虑油水两相具有相同的启动压力梯度，并且启动压力梯度的大小与地层渗透率和含水饱和度有关，同时考虑地层弹塑性变形引起的渗透率改变。在此基础上，建立了符合实际情况的二维油水两相数学模型，并通过IMPES方法进行数值求解，对低渗透油藏注水开发的生产特征，产能影响因素及不同注采井网方式进行了研究，研究表明启动压力梯度、应力敏感性、油水粘度差和毛管力对低渗透油藏产能影响明显。

关键词：低渗透油藏，启动压力梯度，应力敏感性，IMPES方法，数值模拟

Abstract

With the development of modern oil industry, the exploitation of low permeability reservoir has been paid more and more attention in recent years. Compared with medium and high permeability reservoirs, the low permeability reservoir has different seepage flow characteristics,which are as follows: The flow of the fluid does not obey Darcy`s Law; The starting pressure gradient exists in transfusion; The stress sensitivity influence can not neglect.

This paper, based on widespread investigation and study, considered starting pressure gradient and stress sensitivity influence, makes some research on numerical simulation of low permeability reservoir. Specifically, it is considered that oil and water have the same starting pressure gradient, which has the relationship with absolute permeability and water saturation.At the same time, it is also considered that the absolute permeability will vary, because of stratum elastoplasticity distortion. On this basis,a two-dimensional mathematical model of oil-water two-phase is set up, which is solved with the IMPES numerical method. The production characteristics, the factors affecting the deliverability and the different injection pattern were studied. The result indicates that starting pressure gradient、stress sensitivity、oil/water viscosity ratio and capillary pressure have obvious effect to the deliverability of low permeability reservoir.

Key words: Low permeability reservoir, Starting pressure gradient, Stress sensitivity,The method of IMPES, Numerical simulation

目录

摘要 ........................................................................................................................................................ I Abstract .................................................................................................................................................. II 目录 .................................................................................................................................................. I II 1 绪论 . (1)

1.1研究目的和意义 (1)

1.2 国内外研究现状 (1)

1.2.1 低渗透油藏渗流机理及特征研究 (1)

1.2.2 低渗透油藏渗流模型的研究 (3)

1.2.3 低渗透油藏数值模拟技术应用的研究 (5)

1.3 研究内容和技术路线 (5)

1.3.1 研究内容 (5)

1.3.2 技术路线 (7)

2 低渗透油藏渗流基本规律和油藏数值模拟基础 (8)

2.1 低渗透油藏渗流特征 (8)

2.1.1 低渗透油藏渗流呈现非线性特征 (8)

2.1.2 低渗透油藏存在启动压力梯度 (10)

2.1.3 低渗透油藏存在应力敏感性 (12)

2.2 低渗透油藏渗流基本方程 (16)

2.2.1 低渗透油藏运动方程 (16)

2.2.2 低渗透油藏平面径向流公式 (18)

2.3 低渗透油藏数值模拟基础 (19)

2.4 小结 (21)

总结 (22)

参考文献 (23)

致谢 (25)