带油环的底水凝析气藏开发机理研究

【作者】 李星涛；

【导师】 郭肖；

【作者基本信息】 西南石油大学 ， 油气田开发工程， 2010， 硕士

【摘要】 带油环的底水凝析气藏在中国乃至世界都有着广泛分布,具有较高的开发价值。如何最大程度的开采出油环油,如何使凝析油的损失降低到最低,这是目前带油环的底水凝析气藏的开发的重大难题。带油环的底水凝析气藏在开发上存在以下难题：①油气水分布复杂,在整个水动力学系统中,同时存在凝析气、凝析油、油环油、溶解气和地层水等,而在开发动态过程中易出现底水锥进、边水突进、油环油突进气层等；②流体相态复杂,凝析气藏和油环的流体存在不同PVT性质,开发过程中凝析气存在反凝析现象,地层流体饱和度关系变化比较复杂；③流体渗流特征复杂,存在油、气单相流,油水、油气、气水两相流,油气水三相流等流动；④底水锥进,易分割薄油环,油环开采难度大；⑤数值模拟中如何较好的处理带油环凝析气藏流体PVT特征；⑥常规顺层数值模拟网格建模方法无法真实的表征薄油环的分布特征；⑦水平井开采油环可以提高油环的采出程度并延缓底水锥进速度,但是水平井合理的生产参数对油环的采收率和底水锥进影响巨大。这些特殊的开发特征和难题为研究带油环的底水凝析气藏带来较大难度。本文以带油环的底水凝析气藏为研究对象,以准确描述此类油气藏流体分布特征及相态特征模拟处理,水平井提高油环采收率为目标,从凝析气藏的地质特征、开发特征以及开发方式出发,通过对带油环凝析气藏相态特征研究,数学模型建立及求解,混合网格建模技术的研究,分析带油环的底水凝析气藏的开发机理,评价储层非均质程度对开发效果的影响及水平井开发油环合理参数优选,并将成果应用于英买7-19带油环底水凝析气藏。以下是论文取得的主要研究成果：(1)分析了国内外带油环的底水凝析气藏气藏的开发方式,对目前凝析气藏数值模型技术进行研究；(2)对凝析气藏流体相态理论进行研究,对取样流体进行状态方程适应性分析,并对凝析气和油环油开展了PVT实验拟合和相态特征研究,通过气顶凝析气和油环油两套PVT参数场9个拟组分实现了带薄油环凝析气藏流体表征和流体模拟；(3)根据带油环的底水凝析气藏的渗流机理、物质平衡原理、相平衡原理建立了带油环的底水凝析气藏渗流数学模型,并对数学模型进行差分并进行隐式求解；(4)在混合网格建模的理论基础上,利用计算机语言编制生成混合网格的计算机程序,对储层物性参数按照体积加权的方式进行处理,对流体渗流参数进行张量化处理,以混合网格的形式有效表征油环的分布,实现混合网格建模技术,并验证了混合网格的可靠性；(5)建立带油环的凝析气藏机理模型,对储层非均质性对开发效果的影响进行分析；(6)对水平井开发油环的机理进行研究,得出水平井开发带油环凝析气藏的油环油的合理参数；(7)针对英买7-19带油环底水凝析气藏建立混合网格地质模型,油环和凝析气采用两套PVT,对水平井开发油环进行实例模拟,评价水平井开发的效果。更多还原

【Abstract】 Bottom water gas condensate reservoir with oil rim exists widely all over the world and has high exploited value. At present, how to recover most oil in the oil rim and how to decrease the loss of condensate to the minimum degree are the major problems in the development of bottom water gas condensate reservoir with oil rim.There are several problems in development of bottom water gas condensate reservoir with oil rim:①Gas-water distribution is complex. In the whole water dynamics system, there are condensate gas, condensate oil, oil rim, dissolved gas and formation water and so on, and in the development process, bottom water coning, sudden advance of edge water, and sudden advance of oil rim oil into the gas easily appear;②Fluid phase is complex, gas condensate reservoir and the oil rim have different PVT properties, in the development process, phenomenon of retrograde condensation appears in the gas condensate reservoir, and the variation of formation fluid saturation is complex;③Fluid flow characteristics are complex, there is oil and gas single phase flow, oil-water, oil-gas and gas-water two-phase flow, and oil-gas-water three-phase flow;④Bottom water coning easily segments thin oil rim, which makes the development of oil rim difficult;⑤How to deal with fluid PVT characteristics of gas condensate reservoir with the oil rim in the numerical simulation better;⑥Conventional bedding simulation grid modeling methods can not Characterize of true distribution characteristics of thin oil rim;⑦The use of horizontal wells to develop oil rim can increase oil rim recovery and slow down bottom water coning rate, but the reasonable production parameters of horizontal well greatly influence the oil rim recovery and bottom water coning. The special development characteristics and challenges bring more difficulty for researching gas condensate reservoirs with oil rim.In this paper, bottom water gas condensate reservoir with oil rim is regarded as research object, aiming to accurately describe the distribution of these reservoir fluids, phase characteristics simulating and use horizontal wells to improve oil recovery. From the angle of gas condensate reservoirs geological characteristics, development characteristics and the development mode, through analyzing phase characteristics of gas condensate reservoir with oil rim, establishing mathematical model and resolution, researching mixed grid modeling technology, effect of sand heterogeneity degree on the development is analyze and the reasonable production parameters of horizontal well developing oil rim are optimized. Finally, the results of researching bottom water gas condensate reservoir with oil rim are applied to Yingmai 7-19 bottom water gas condensate reservoir with oil rim. The paper’s main findings are as follows:(1) The development methods of bottom water gas condensate reservoir with oil rim at home and abroad are analyzed and the current numerical simulation of gas condensate reservoir is researched;(2) Fluid phase behavior theory of gas condensate reservoir is researched and adaptability of the fluid equation of state by sampling is carried on. Then, PVT experiment fitting and phase behavior of condensate gas and oil rim are researched. Fluid characteristics and fluid simulation are achieved by cap.condensate gas and oil rim with two PVT parameters and 9 components.(3) According to the flow mechanisms of bottom water gas condensate reservoir with oil rim, material balance principle and equilibrium principle, mathematical model of bottom water gas condensate reservoir with oil rim is established and the mathematical model is differenced and implicit solution is carried out;(4) Based on theory of modeling mixed grid, computer program of mixed grid is generated by computer language. The reservoir parameters are treated by the volume-weighted approach and fluid flow parameters are treated by tensor analysis. Distribution of oil rim is characterized in the way of mixed grid. Modeling technique of mixed grid is achieved and the reliability of the mixed grid is verified;(5) Mechanism model of bottom water gas condensate reservoir with oil rim is established and effect of reservoir heterogeneity on the development is analyzed;(6) Mechanism of horizontal wells developing oil rim is studied and reasonable parameters of condensate gas reservoir with oil rim developed by horizontal well are obtained;(7) The mixed grid geological model for Yingmai 7-19 bottom water gas condensate reservoir with oil rim is established, The case of oil rim developed by horizontal well is simulated by two PVT of oil rim and condensate gas,and the effect of horizontal well developing oil rim is evaluated.更多还原