缝洞型油藏注气提高采收率研究

发布时间：2018-04-24 10:24

本文选题：缝洞型油藏 + 注气　；参考：《长江大学》2015年硕士论文

【摘要】：缝洞型油藏在世界油气资源中占有十分重要的位置,这类油藏储层非均质性严重,流体分布复杂,缝洞本身的多尺度性和连通多样性给开发造成困难。近几年随着塔河油田缝洞型油藏的不断开采,对缝洞型油藏的开发有一定的认识。塔河油田在前期通过注水替油和单元注水来缓解油藏产量递减的情况,但是在开发后期,注水替油效果变差,含水率上升过快,残存在缝洞高部位的“阁楼油”难以采出,仅仅采用注水措施已经很难满足开发需求。国内外开发研究表明,对于后期高含水油藏,注气是一种行之有效的方法。对油藏注气可以通过重力分异、恢复地层压力、降低原油粘度等机理改善油藏开发效果,进一步提高原油采收率。本文的研究内容主要来自中国石化西北石油局的研究课题。在经过大量的相关文献调研后,本文根据相似准则,以油藏缝洞分布规律为基础设计了耐高温高压全直径缝洞气驱物理模型以及单井替油模型,运用该实验装置完成注氮气室内替油实验,分析哪种方式最有利于油藏开发,本文主要完成的内容有：1、完成单井模型中底水、注气方式以及油藏含油体积对注气采收率的影响。研究结果表明：底水充足时可利用底水能量驱油,在注气轮次相同时底水充足油藏注气采收率高于无底水；实验针对底水油藏采用了单纯注气、水气交替及水气混注三种方式,底水驱过后残存在单井上部的“阁楼油”难以采出,通过注气可以驱出部分剩余油,控制底水锥进速度,最终得出在底水充足时单纯注气方式效果最好；在油藏含油体积大时采用注气方式效果更加显著。2、完成缝洞型物理模型驱油实验,主要研究了氮气驱替、注气速度、原油粘度、注气方式对采收率的影响。研究表明：在进行水驱过后缝洞模型中存有部分剩余油,通过注气后可以改善液体流动条件,进一步提高采收率；注汽速度的选择会影响最终采出程度,存在一个最佳注入速度,使得气体能够进入裂缝与原油充分混合而不至于过早发生气体突破；同时还对比了非均质条件不同注气方式对采收率的影响.,实验结果表明,非均质性严重的缝洞油藏采用注气替油方式能开采出驱替方式中无法波及到的低渗透单元。
[Abstract]:Fracture-cavity reservoirs play a very important role in the world's oil and gas resources. The reservoir heterogeneity is serious, fluid distribution is complex, and the multiscale and connected diversity of fractures and cavities makes the development difficult. In recent years, with the continuous development of fracture-cavity reservoirs in Tahe Oilfield, there is a certain understanding of the development of fracture-cavernous reservoirs. In Tahe Oilfield, oil displacement and unit water injection were used in the early stage to alleviate the decline of reservoir production. However, in the later stage of development, the effect of replacing oil with water was poor, the water cut increased too quickly, and it was difficult to produce the "loft oil" remaining in the high part of fracture and cavity. It is difficult to meet the development demand by using water injection measures alone. Domestic and foreign development studies show that gas injection is an effective method for late high water cut reservoirs. Through gravity differentiation, recovery of formation pressure, reduction of oil viscosity and other mechanisms, gas injection can improve reservoir development efficiency and further improve oil recovery. The research content of this paper mainly comes from the research subject of Northwest Petroleum Bureau of Sinopec. After a lot of related literature research, based on the similarity criterion, the physical model of high temperature and high pressure diameter gas drive and the model of single well replacement oil are designed based on the distribution of fracture and cavity in oil reservoir. In this paper, the main contents of this paper are as follows: 1, the effect of bottom water, gas injection mode and oil volume of single well model on gas injection recovery. The results show that when the bottom water is sufficient, the bottom water energy can be used to drive oil, and the gas injection recovery factor of the bottom water sufficient reservoir is higher than that of the bottom water reservoir when the gas injection wheel times are the same, and three methods of pure gas injection, water gas alternating and water gas mixing injection are adopted in the experiment for the bottom water reservoir. The "loft oil" remaining in the upper part of a single well after the bottom water drive is difficult to be produced. Through gas injection, part of the remaining oil can be driven out, and the bottom water coning speed can be controlled. Finally, it is concluded that the gas injection mode is the best when the bottom water is sufficient. When the volume of oil is large, the effect of gas injection is more remarkable. The oil displacement experiment of fracture-cavity physical model is completed. The effects of nitrogen displacement, gas injection velocity, crude oil viscosity and gas injection mode on oil recovery are mainly studied. The results show that there are some residual oil in the fracture and cavity model after water flooding, which can improve the liquid flow condition and further increase the recovery factor after gas injection, and the choice of steam injection speed will affect the final recovery degree. There is an optimal injection rate, so that the gas can enter into the fracture and crude oil to fully mix without premature gas breakthrough, and at the same time, the effects of different injection modes of heterogeneous conditions on oil recovery are compared. The experimental results show that, Low permeability units can be produced by gas injection instead of oil in a fractured reservoir with serious heterogeneity.
【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】：TE357.7

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