【作者】 葛永涛；

【导师】 樊泽霞；

【作者基本信息】 中国石油大学 ， 油气田开发工程， 2008， 硕士

【摘要】 在江苏油田已投入开发的油藏中,真武油田真35断块等属于高含水开发单元,总体上来看,在开发期间通过转注采油井、完善井网及细分层系等合理调整部署,使开发效果明显改善,但是由于物性差、层间及平面矛盾突出、水窜严重,同时受地层条件限制,多数油井受效方向单一,注采结构不合理,导致近几年油田进入高含水期后,开发效果变差,采油速度在0.3～0.8%之间,日产水平维持在12t/d～18t/d的水平,从含水与采出程度关系曲线可见,目前曲线呈锯齿状斜直线趋势上升;通过存水率评价分析发现,大量的注入水被低效采出,充分说明针对真35块E2d2,无论从经济上还是技术上来说,常规的二次采油开发调整方法都不能够满足降本增效、降水增油的目的,油田目前开采现状明显不适应开发后期提高采收率的需要,油田的可持续发展面临着严峻的挑战,水驱开发后期当务之急的任务是寻找更有效可行的挖潜技术提高可采储量。要提高该断块的开发效果必须采取相应的三次采油措施。聚合物驱是向油藏中注入高相对分子质量的水溶性聚合物溶液的驱油方法。聚合物通过溶于水中,形成聚合物溶液,增加水相的粘度来提高采收率,主要有两项驱油机理:一是增粘——改善油水流度比,调整吸水剖面,即扩大波及体积;二是具有改变油水界面粘弹性的作用,使得油滴或油段易于拉伸变形,容易通过阻力较小的狭窄喉道,从而提高驱油效率。因此,注入高粘度的聚合物溶液,可以加大高渗透率层段水突破时低渗透率层段的水线推进距离,调整吸水剖面,扩大驱剂的波及体积,提高采收率。本文针对真武油田真35块开发现状,通过构造和储层特征的研究和水驱开发效果评价,从静态和动态上,全面分析了目前该断块开发中所存在的问题,在对国内外聚合物驱调研的基础上,针对真35断块E2d2层系的地质、开发特征,进行了高含水期聚合物井网调整和部署以及聚合物筛选与评价,通过精细建模和历史拟合,定量描述了该区块水驱至目前储量动用状况及剩余油分布规律及特征,并利用ECLIPSE软件的化学驱模块,对聚合物的不同段塞、浓度、注入速度等注入参数进行了优化计算,确定最佳方案。更多还原

【Abstract】 After long-term water-flooding development, Zhen 35 fault block in Jiangsu oilfield has stepped into high water cut stage. Totally speaking, some reasonable adjust distributions, such as transferring to injection of production well, well pattern improvement and layer system subdivision, have improved the development effect significantly. However, in virtue of poor physical property, apparent interlamination and plain difference, serious water breakthrough, as well as restricted formation conditions, most of the producer response in the single direction, and injector producer framework is not reasonable. During high water cut stage in the recent years, these situations above make development effects poor, when oil production rate is within 0.3 to 0.8 percent and oil daily production rate is about 12 to 18 tons per day. The relation curve of water cut and reserve recovery degree shows that it rises in the tendency of serration and slanted line. It can be found that lots of injected water is produced with low efficient by evaluation analysis of water cut, which indicates sufficiently, it can’t attain the target of cost and water cut reduction, as well as efficiency and oil production improvement, by traditional adjustment methods of secondary recovery development in the E2d2 Unit of Block Zhen 35, regardless of economically or technologically. Now, present situations of the oilfield apparently cannot meet EOR in the production tail, and sustainable development of it is faced with rigor challenge. A top priority task is to find valid and feasible tap the latent power technologies for recoverable reserves improvement during the stage, and it is necessary to take relevant measures of tertiary recovery for EOR. Polymer flooding is an oil displacement method by injecting high molecular weight and water-soluble polymer into the reservoir. The main mechanisms of polymer flooding to enhance the oil recovery include: viscosifying action, which can improve mobility ratio of oil to water, adjust injection profile, and so enlarge swept volume; changing the viscoelastic property of water-oil interface, which make the oil droplet or oil slug stretch elongation easy, go through the narrow throat with smaller resistance, and so increase the displacement efficiency. Therefore, the injection of high viscosity polymer solution can widen the advancing distance of waterline in the low permeability layer when it breakthrough in the high permeability layer, adjust injection profile, expand swept volume of displacing agent, and so increase the oil recovery.In view of the current exploitation status of Zhen 35 fault block, this thesis analyzed the problems encountered in the development process by studying the reservoir structure and characteristics and evaluating the development effect of water flooding. On the basis of investigating polymer flooding home and abroad, adjustment and deployment of well pattern and evaluation of polymer have been carried out according to the geologic characteristics and development features of E2d2 layer system in Zhen 35 fault block. The producing reserves state and remaining oil distribution rule have been described quantitatively by means of fine modeling and history matching. Moreover, some injection parameters, such as the different slug, concentration, and injection rate of polymer, have been optimized using the chemical flood module of the ECLIPSE software and the optimum scheme was determined.更多还原