提高气举采油系统效率应用基础研究

【作者】 刘三威；

【导师】 杜志敏； 李颖川；

【作者基本信息】 西南石油学院 ， 油气田开发工程， 2004， 博士

【摘要】 气举采油作为机械采油方法之一，在美国应用较为广泛，就其产量而言仅次于有杆泵采油，起着举足轻重的作用。我国已在中原、吐哈、塔里木、四川、南海等油气田得到了应用，已初步形成了一定的气举生产规模。气举具有产液量变化范围大、举升深度深、操作管理简便等优点，尤其适于高气液比、出砂严重、含腐蚀性介质、定向井等复杂条件的油井。因此，气举采油技术对于开发西部油田和海上油田更具有强大优势，提高气举系统效率亦成为气举采油技术的研究热点。 气举采油系统性极强，由压缩机组、配气管网、气举井、集输管网四部分串联组成。任一子系统的波动都将影响整个系统的运行。压缩机组作为气举采油的动力源，其气量直接影响气举采油的规模，而动力机的选择也将直接影响整个气举系统的经济效益；配气管网作为能量的中间传递者，其输出压力与温度将直接影响气举井的工艺设计，从而影响气举井的工况；气举井作为气举系统的核心，也是能量消耗的主要场所，气举井的经济效益高低将直接决定气举系统经济效率的高低；集输管网起能量转移的作用，但计量站回压直接与气举井井口回压相关联，从而影响气举井的正常运行。 与有杆抽油系统相比，气举系统各子系统极其分散，具有不同类型的动力设备驱动的多个机组同时工作的动力系统、纵横交错的能量传递系统、极其复杂的举升系统以及高气液比大流量的运输系统。如何正确评价各子系统的能耗情况，特别是气举井子系统的能耗分析；针对各个单井的具体情况，采取怎样的工艺措施，以达到节能增效的目的，以及如何在限量的气源情况下获取更高的经济效益，已成为目前气举采油的技术关键。 本文旨在通过描述气举各子系统的能量转换规律，建立一套现场实用的能耗指标体系，以文东油田气举系统为实例，针对各子系统的能耗利用情况，提出合理的工艺技术措施以提高整个气举系统的效率。对于高产液井，重点研究连续气举井优化设计技术；对于低产量低压井，提出柱塞气举、单管柱球塞连续气举新工艺。在此基础上，以区块总产油量和经济效益为目标，建立了多井的优化配气数学模型，使各气举井的气量分配更合理，从而提高了高压气源的利用率。本文研究取得了以下主要成果和认识： (1) 气举系统效率评价模型方面 本文将气举系统分为压缩机组、配气管网、气举井、集输管网四个子系统，综合考虑了气体热膨胀、动能、位能等，建立了描述各子系统流动规律相应的数学模型，提出了各子系统的效率评价方法。在此基础上，建立了一套实用的气举系统效率评价摘要指标体系，结合气举井经济效益，建立了气举井效率控制图.应用文东油田的68口气举井测试数据，统计分析了气举子系统能耗情况，重点分析了注气量、注入气液比、注入压力等因素对气举井效率的影响，为气举井的设计提供了明确的目标。统计分析表明:气举井滑脱损失是气举井效率低的主要原因，亦是气举系统效率低的主要原因。因此，提高气举系统效率主要围绕提高气举井效率进行。 (2)提高气举井效率的措施方面 基于对地层流入动态以及井筒多相管流的分析，确定了适合气举条件下的油井流入动态模型以及适于高气液比下的井筒多相管流模型，应用气举阀动态特性实验结果，对比分析了国产与进口气举阀的各项性能参数的差异，改进了气举井布阀设计方法，使气举井阀分布更合理，以提高气举井效率。 对低能量井采用柱塞气举，研制了柱塞气举配套工具，实现了柱塞气举配套工具国产化;建立了柱塞气举动力学模型，对柱塞气举进行了优化设计，为柱塞气举的现场应用提供了重要的技术保障。鉴于低压井连续气举滑脱损失严重，提出了适合于文东油田5’厅套管的单管球塞连续气举工艺，模拟分析计算表明，该工艺能明显降低滑脱损失，提高举升效率，有望成为连续气举的接替工艺。 (3)区块优化配气方面 针对高压气源严重不足，进而制约气举规模的问题，结合气举井特性曲线，建立了气举井经济动态模型和以区块(多井)总产量与经济效益为目标的双目标优化配气模型，为气举的进一步推广提供了重要的技术依据。 对文东油田气举系统进行了效率评价，针对各种类型的典型井，应用相应的工艺措施，已获得了显著的经济效益和社会效益。主题词:人工举升气举采油系统效率优化配气更多还原

【Abstract】 Gas lift is a kind of mechanical oil production used widely and early, which plays a great role in production engineering and next to the sucker-rod pumping in oil production. In China, gas lift is popularized in Zhongyuan, Tuha, Talimu, Sichuan, Nanhai and so on. With western oilfield and offshore oilfield developed, gas lift has huge attractiveness and vitality for gas lift has many strongpoint that gas lift adapt to deep well, high productivity, complex layer and complex exploitation condition. So how to improve the efficiency of gas-lift system is hotspot.Gas lift is a kind of artificial lifts that has much strong systematization. Gas-lift system is comprised of gas-lift pumping plant, gas distribution network, gas-lift well, pipeline between gas-lift well and metering station. And that each one of the last four parts has changed will affect operation of the gas-lift system. The gas-lift pumping plant is the power source, the gas volume has a direct effect on the scale of gas lift and the selection of power motor will directly affect the cost of gas-lift system. The gas distribution network handed down the gas energy, the pressure and the temperature of the end have an direct effect on the technology design of gas-lift well, as a result, the operation of gas-lift well is affected. Gas-lift well is the heart of gas-lift system and the main location that the energy is wasted. The economic benefit of gas-lift well will decide that of the gas-lift system. The pipeline between gas-lift well and metering station play a role of moving energy, but the back pressure in the metering station is relevant to the wellhead back pressure, so it will affect the work of the gas-lift well.As the rod pumping system, the four parts of gas-lift system is divided and each part is much complicated and flow law is not same in any two parts. How to value the energy consumption of each part, on the results how to take aimed measures to improve the efficiency of gas-lift system and how to get max economic benefit on the condition of limited gas resource is the critical technology of gas lift.By describing energy conversion of four parts, a series of energy index is established. Computation on the test data from Wendong field indicates energy consumption and based on the statistic analysis aimed measures is taken to improve the efficiency os gas-lift system. Because the energy loss of gas-lift well is more than the others, much attention is paid to the measures of gas-lift well: to high-productivity well, the optimized design is used; to those wells with low productivity and low bottom-hole producing pressure, the plunger gas lift and new pig lift with one pipe string is advised. Based on the study of individual well, the optimized mathematic model is established to get max oil production and max economic benefit. So the gas resource is used in reason, In this thesis, the main achievements and recognitions is as follows:(1) Mathematic model of the efficiency of gas-lift systemIn this thesis, the gas-lift system is comprised of gas-lift pumping plant, gas distribution network, gas-lift well, and pipes between gas-lift well and metering station. Mathematical model is established to describe flow rule of four parts and the method to calculate theefficiency is given. As a result, a series of index is made. Combined with the economic benefit of gas-lift well, control chart of gas-lift well is built. Computation on the test data from Wendong field indicates that the proposed model performs well. The efficiency and energy consumption of the four parts are analyzed by statistics. What is more, the factors that affect the efficiency of gas-lift well are analyzed such as injection gas volume, injection gas/liquid ratio, injection pressure etc. It indicates that the slip loss in gas lift well is the main factor, which make the efficiency of gas-lift well and that of gas-lift system low. The measures to improve the efficiency of gas-lift system focus on how to make the efficiency of gas-lift well high.(2) The measures to improve the efficiency of gas-li更多还原