L3区块低渗致密油藏注气开发方式研究

发布时间：2018-04-22 13:40

本文选题：低渗致密油藏 + CO_2混相驱　；参考：《西南石油大学》2015年硕士论文

【摘要】：我国有丰富的低渗油气资源,日前已探明的地质储量达70多亿吨,开发致密油气藏对于缓解我国能源供应紧张具有重要的意义。但由于低渗致密油藏具有低孔、低渗、自然产能低、储层物性差等特征,大多数致密油藏衰竭开采采收率较低,一般不超过5%,注水开发由于储层的强非均质性效果也不是很理想,一般也只有20%左右。为了提高低渗致密油藏的采收率,迫切需要研究新的开发方式。国内外大量研究结果表明,注CO2气体开发致密油是一种有效的提高采收率的方法。同时,利用CO2作为注入气还可以减轻温室效应,对保护环境也具有重要的意义,CO2驱油逐步成为提高致密油等非常规油气藏采收率的一项新技术,具有良好的发展前景。川中L3区块致密油藏具有低孔、特低孔、超低渗、高压的特点,同时储集层类型为裂缝型、裂缝-孔隙型,由于裂缝的存在,储集层具有较强的非均质性。L3区块衰竭和注水开发效果都不理想,开发难度大,但该区块具有可观的地质储量,有必要进行注CO2气体开发的探索性研究。针对L3区块低渗致密油藏,利用数值模拟,结合室内实验,开展了低渗致密油藏注CO2气开发研究。在模拟储层条件下,进行室内实验测定了L3区块储层流体的PVT特性,主要进行了闪蒸实验、等组分膨胀实验、多级脱气实验以及注气膨胀实验,得到了储层流体参数以及地层原油注入C02后油气相态的变化规律。运用相态模拟软件对PVT实验及注气膨胀实验进行了成功拟合,为后续开展注气开发方式数值模拟研究提供了流体物性数据。同时,在相态拟合的基础上,利用模拟细管实验和经验公式方法得到了L3区块致密油与CO2的最小混相压力。根据L3区块的储集层特征以及开发现状,应用数值模拟软件对注CO2气体开发方式进行了研究。最终推荐开发方案为：注气量为6000m3/d,采用矩形五点井网进行开采,井距为450m时注气开发效果较优,预测十年采出程度可达42.25%,比水驱采出程度提高了15%,明显提高了原油的采出程度,则注气开开发L3区块低渗致密油藏是可行的。本文推荐方案已被现场采纳,准备在现场试点CO2驱先导试验工作。研究结果对其他同类型强非均质低渗致密油田进行注气开发具有重要的指导意义。
[Abstract]:There are abundant low permeability oil and gas resources in China, and the proved geological reserves amount to more than 7 billion tons. It is of great significance to develop dense oil and gas reservoirs to alleviate the shortage of energy supply in China. However, due to the characteristics of low porosity, low permeability, low natural productivity and poor reservoir physical properties, most tight reservoirs have low recovery efficiency. Generally, the water injection development is not ideal because of the strong heterogeneity of reservoir, and it is only about 20%. In order to improve the recovery of low permeability tight reservoirs, it is urgent to study new development methods. A large number of research results at home and abroad show that the injection of CO2 gas to develop dense oil is an effective method to improve oil recovery. At the same time, the use of CO2 as injection gas can also reduce Greenhouse Effect, which is also of great significance to the protection of the environment. CO2 flooding has gradually become a new technology for improving oil recovery in unconventional reservoirs, such as dense oil, and has a good development prospect. The tight reservoir of L3 block in central Sichuan has the characteristics of low porosity, ultra-low porosity, ultra-low permeability and high pressure. At the same time, the reservoir type is fracture type, fracture-pore type, because of the existence of fracture. Reservoir has strong heterogeneity. L3 block failure and water injection development effect are not ideal, but the block has considerable geological reserves, it is necessary to explore the development of CO2 gas injection. For low permeability dense reservoirs in L3 block, the CO2 gas injection development of low permeability dense reservoirs was studied by numerical simulation and laboratory experiments. Under simulated reservoir conditions, the PVT characteristics of reservoir fluid in L3 block were measured by laboratory experiments, including flash test, iso-component expansion experiment, multistage degassing experiment and gas injection expansion experiment. The fluid parameters of the reservoir and the variation law of the oil and gas phase state after the injection of the formation crude oil into CO2 are obtained. The phase simulation software is used to fit the PVT experiment and the gas injection expansion experiment successfully, which provides the fluid physical property data for the subsequent numerical simulation study of the gas injection development mode. At the same time, on the basis of phase state fitting, the minimum miscible pressure between compact oil and CO2 in L3 block is obtained by using the simulated thin tube experiment and empirical formula method. According to the reservoir characteristics and development status of L3 block, a numerical simulation software was used to study the development mode of injected CO2 gas. The final recommended development plan is as follows: the gas injection rate is 6 000 m3 / d, the rectangular five dot pattern is used for production, the gas injection development effect is better when the well spacing is 450 m, the predicted recovery degree can reach 42.25% in ten years, the recovery degree is 15 times higher than that of water flooding, and the recovery degree of crude oil is obviously improved. It is feasible to develop low permeability tight reservoir in L 3 block by gas injection. The recommended scheme has been adopted in the field and is ready to pilot pilot pilot test of CO2 drive in the field. The results are of great significance for the development of gas injection in other dense oil fields with strong heterogeneity and low permeability.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE357.7

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