基于非线性渗流的水驱稠油油藏数值模拟技术研究

发布时间：2018-03-01 11:23

本文关键词： 稠油非线性渗流数值模拟软件　出处：《长江大学》2015年硕士论文　论文类型：学位论文

【摘要】：近年来,随着我国经济快速发展以及人们物质生活水平的提高,人们对石油和天然气的需求与日俱增,但现在我国常规原油的开发已进入中后期,原油产量逐日递减已远远不能满足人们消费需求。2013年9月,我国成为全球最大的石油消费国,日均进口石油达到630万吨,超过了美国的624万吨日均石油进口水平。美国能源信息署(EIA)预测这一形势将会持续,并且双方之间的日均石油进口差距还会进一步扩大。为了缓解这种局势,减少我国石油对外依赖度,对于非常规油气藏的勘探与开发也就显得越来越重要。其中稠油以其巨大的储量优势对改善我国能源结构、缓解石油供需压力具有重大现实意义。与常规油藏不同的是稠油富含胶质、沥青质、蜡等高分子聚合物使得其粘度高、流动性能差,流变性有别于一般牛顿流体,呈现非牛顿渗流特性,这些因素都使得稠油的开采难于常规原油。油藏数值模拟技术作为油藏开发的有效辅助工具,可以为更好地开发稠油油藏提供一定的技术支持。油藏数值模拟是用数值方法求解描述油气水运动的数学模型来研究油气水在油气藏中的运动规律,是新油气田开发方案设计、老油气田开发方案调整与提高采收率方法选择与方案设计的一种有力手段,为提高采收率和经济效益服务。但是目前常用的商业化油藏数值模拟软件大都基于达西渗流规律而建立,若是利用这些软件对存在着非线性渗流的稠油油藏进行模拟,得到的结果难免会出现较大偏差,预测的生产指标也会与生产实际相去甚远。为了提高预测准确度,更好地开发稠油油藏,迫切需要研制一套能够对稠油油藏进行准确模拟的油藏数值模拟软件。本文通过实验对稠油流变性以及非线性渗流规律进行研究,在黑油模型的基础上建立了闪蒸黑油模型,分析稠油非线性渗流与达西渗流方程之间的差别,引入视粘度概念,通过流动修正系数将稠油非线性模块嵌入到闪蒸黑油模型中,研制出稠油油藏非线性渗流数值模拟软件,该软件考虑了稠油非线性渗流的影响,弥补了常规油藏数值模拟软件不能体现稠油非线性渗流的不足,通过了可靠性检验,并利用该软件对实际油藏进行模拟,得到了较为理想的结果。本文完成的主要工作有：(1)稠油流变性实验：秦皇岛32-6油田与绥中36-1油田稠油剪切应力和剪切速率之间不再是简单线性关系,而是呈现出明显的非线性关系,具有非牛顿流体的流变特性；温度对稠油流变曲线的影响较大,相同的剪切速率下,温度越高,对应的剪切应力越低；当剪切速率为40/s时,秦皇岛32-6油田稠油在25℃C时的剪切应力是70℃C时的4倍还多,对于绥中36-1油田,当剪切速率为40/s时,其25℃C时的剪切应力与70℃C时的比值约为3；等温,等剪切速率下,秦皇岛32-6油田稠油剪切应力要高于绥中36-1油田稠油,说明秦皇岛32-6油田稠油粘度要高于绥中36-1油田；稠油粘度变化在不同的剪切速率范围内表现不同,在剪切速率比较低的情况下,稠油粘度随剪切速率的增加减小速率较快,但在相对较高的剪切速率下,稠油粘度随剪切速率的增加减小速率变慢；温度是影响稠油粘度的重要因素,对稠油粘度的影响较大,相同的剪切速率下,不同温度条件下对应的稠油粘度相差较大。(2)稠油非线性渗流规律：在原油粘度相同的条件下,稠油启动压力梯度随着渗透率的增加而减小；在渗透率相同的条件下,稠油启动压力梯度随着原油粘度的增加而增加；稠油启动压力梯度与流度具有一定的乘幂关系,启动压力梯度随流度的增加而减小；渗透率与粘度是影响稠油启动压力梯度的主因,利用流度来表征启动压力梯度则是综合了这两个因素。(3)闪蒸黑油模型：参考黑油模型的设计以及实现的基础上,建立闪蒸黑油模型,内容包括：①建立数学模型,包括数学模型的假设条件、运动方程、微分方程、辅助方程和定解条件；②建立数值模型,包括数值求解方法、差分方程、油气组分平衡方程；③参数的取值以及处理,包括渗透率的取值以及井产量处理；④最后给出闪蒸黑油模型求解过程。(4)稠油油藏非线性渗流模块：对比稠油非线性渗流与达西渗流方程之间差别,引入视粘度概念,通过流动修正系数将稠油非线性模块嵌入到闪蒸黑油模型中,使稠油非线性渗流能够在模型中得以实现。(5)稠油油藏非线性渗流数值模拟软件：编制稠油油藏非线性渗流数值模拟软件,对其可靠性进行检验,检验内容包括零平衡、对称性检验以及与成熟商用模拟软件计算结果进行对比,检验结果表明稠油油藏非线性渗流数值模拟软件完全能够用于油藏数值模拟计算。(6)稠油油藏非线性渗流数值模拟软件应用：利用软件对实际稠油油藏进行模拟,模拟结果表明启动压力梯度越大,日产油量越少,含水率上升越快,原油采出程度越低；为改善稠油油藏开发效果,可采用热采方式对稠油油藏进行开发,提高地层温度,降低地层原油粘度,增加流度,减小启动压力梯度,最大限度地降低启动压力梯度对生产的影响。
[Abstract]:In recent years, with China's rapid economic development and the improvement of people's living standards, people's demand for oil and natural gas development in China now grow with each passing day, but conventional crude oil has entered the stage, diminishing daily crude oil production has been far can not meet the consumer demand for people to.2013 in September, China has become the world's largest consumer of oil daily, oil imports reached 6 million 300 thousand tons, 6 million 240 thousand tons more than the U.S. average daily oil imports. The U.S. Energy Information Administration (EIA) to predict the situation will continue, and between the two sides of the average daily oil imports will further expand the gap. In order to alleviate this situation, reduce our dependence on foreign oil, more important for unconventional the exploration and development of oil and gas reservoir is more and more. The heavy oil of its huge reserves advantages to improve China's energy structure, ease the pressure of oil supply and demand are important now Real meaning. Different from the conventional heavy oil reservoir is rich in colloid, asphaltene, wax and other polymers due to its high viscosity and poor flow properties, rheological property is different from the general Newton fluid, present seepage characteristics of non Newton, these factors make the exploitation of heavy oil to conventional raw oil. Simulation technology as an effective auxiliary tool for reservoir development the reservoir can provide technical support for the better development of heavy oil reservoir. The reservoir numerical simulation is to study the motion law of oil and gas and water in reservoir by using numerical method for solving the mathematical model describing the oil gas water movement, is the new oil and gas field development project design, adjustment and development plan of old oil and gas recovery a powerful tool design method and scheme of rate, improving the recovery efficiency and economic benefit. But the present numerical simulation software commonly used in commercial reservoir are mainly based on the Darcy seepage The law established, if the existence of heavy oil reservoir of nonlinear flow was simulated by the software, the result will inevitably appear larger deviation, the production index prediction will also with the actual production far. In order to improve the prediction accuracy, the better development of heavy oil reservoir, the urgent need to develop a simulation software of numerical reservoir accurately simulation of heavy oil reservoirs. The experimental research on crude oil rheology and nonlinear seepage law, on the basis of the black oil model flash black oil model, nonlinear analysis between heavy oil seepage and Darcy flow equation difference, the apparent viscosity of heavy oil will be introduced the concept of nonlinear module embedded into the flash flow through the black oil model the correction coefficient, developed numerical simulation software of nonlinear seepage flow of heavy oil reservoir, the software considering the effect of nonlinear seepage for heavy oil. Lack of numerical simulation software can not reflect the conventional nonlinear percolation of heavy oil reservoir, through the reliability test, and the actual reservoir is simulated by the software, and an ideal result is obtained. The main works are as follows: (1) 32-6 heavy oil rheology experiment: Qinhuangdao oilfield and Suizhong oilfield 36-1 between shear stress and shear the rate is no longer a simple linear relationship, but showing obvious nonlinear relationship, with rheological properties of non Newtonian fluid; effect of temperature on the rheological curve of the larger, the same shear rate, the higher the temperature is, the shear stress is low; when the shear rate is 40/s, 32-6 of Qinhuangdao Oilfield in 25 C C when the shear stress is 4 times more than 70 DEG C, for the 36-1 Suizhong oil field, when the shear rate is 40/s, the ratio of shear stress at 25 DEG C and 70 DEG C when the C is about 3; isothermal, Such as shear rate, shear stress in Qinhuangdao oilfield 32-6 to 36-1 higher than Suizhong oilfield, Qinhuangdao oilfield 32-6 heavy oil viscosity is higher than Suizhong 36-1 oilfield; performance in different ranges of shear rates viscosity in different shear rate is relatively low, in the case of heavy oil viscosity with the increase of the shear rate decreases in a faster rate however, at relatively high shear rates, the viscosity decreases with the increase of the shear rate slows down; temperature is an important factor affecting the viscosity, influence on the viscosity of heavy oil is larger, the same shear rate, the viscosity of heavy oil under different temperature conditions corresponding to large difference. (2): in the nonlinear seepage law of heavy oil under the same conditions the viscosity of crude oil, heavy oil starting pressure gradient decreases with the increase in permeability; permeability under the same conditions, the starting pressure gradient along with the original heavy oil Increase of oil viscosity increases; heavy oil starting pressure gradient and flow has a certain power relationship, the starting pressure gradient decreases with the increase of permeability and fluidity; heavy oil viscosity is the main reason to start pressure gradient, the flow to the starting pressure gradient is a comprehensive characterization of these two factors. (3) flash black oil model reference: black oil model design and implementation, the establishment of flash black oil model, including: the establishment of mathematical model, assumptions, including the mathematical model of motion equations, differential equations, auxiliary equations and boundary conditions; the establishment of numerical model, including numerical method, differential equation, oil and Gas Group balance equation; the value of the parameters and processing, including permeability values and well production processing; finally, the solution of flash black oil model. (4) the line of non oil reservoir seepage module: The difference between the comparison of nonlinear percolation of heavy oil with Darcy flow equation, introducing the concept of apparent viscosity, the heavy nonlinear module embedded into the flash black oil model through the flow coefficient, the nonlinear percolation of heavy oil can be realized in the model. (5) the nonlinear seepage flow of heavy oil reservoir numerical simulation software, a numerical simulation software of nonlinear seepage flow of heavy oil reservoir developed. To test its reliability test, including zero balance, symmetry test and commercial simulation software by comparing the calculation results, the test results show that the nonlinear seepage flow of heavy oil reservoir numerical simulation software can be used in oil reservoir numerical simulation computing. (6) using numerical simulation of nonlinear seepage flow of heavy oil reservoir of heavy oil reservoir were simulated using the actual the software, the simulation results show that the higher the starting pressure gradient, Nissan oil content is less, water cut rises faster, crude oil In order to improve the development effect of heavy oil reservoirs, the thermal recovery method can be used to develop heavy oil reservoirs, improve the formation temperature, reduce the viscosity of the crude oil, increase the mobility, reduce the starting pressure gradient, and minimize the influence of start-up pressure gradient on production.

【学位授予单位】：长江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE357.6

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