Research progress and potential of new enhanced oil recovery methods in oilfield development

This paper reviews the basic research means for oilfield development and also the researches and tests of enhanced oil recovery(EOR)methods for mature oilfields and continental shale oil development,analyzes the problems of EOR methods,and proposes the relevant research prospects.The basic research means for oilfield development include in-situ acquisition of formation rock/fluid samples and non-destructive testing.The EOR methods for conventional and shale oil development are classified as improved water flooding(e.g.nano-water flooding),chemical flooding(e.g.low-concentration middle-phase micro-emulsion flooding),gas flooding(e.g.micro/nano bubble flooding),thermal recovery(e.g.air injection thermal-aided miscible flooding),and multi-cluster uniform fracturing/water-free fracturing,which are discussed in this paper for their mechanisms,approaches,and key technique researches and field tests.These methods have been studied with remarkable progress,and some achieved ideal results in field tests.Nonetheless,some problems still exist,such as inadequate research on mechanisms,imperfect matching technologies,and incomplete industrial chains.It is proposed to further strengthen the basic researches and expand the field tests,thereby driving the formation,promotion and application of new technologies.

Deepwater and Deep Layers： the Strategic Choices for China＇s Oil and Gas Resources Development

On December 2, 2017, the 2nd Seminar on the Development Strategy of China＇s Oil and Gas Resources was held in Beijing. This seminar was hosted by the Strategic Research Center for Oil and Gas Resources, Ministry of Land （MLR） and Resources and sponsored by both the CNOOC Exploration Department and the School of Ocean and Earth Sciences of Tongji University. With the theme of ＂deepwater and deep-layer oil and gas resources and development strategy＂,

Technological progress and development directions of PetroChina overseas oil and gas field production

This study reviews the development history of PetroChina’s overseas oil and gas field development technologies, summarizes the characteristic technologies developed, and puts forward the development goals and technological development directions of overseas business to overcome the challenges met in overseas oil and gas production. In the course of PetroChina’s overseas oil and gas field production practice of more than 20 years, a series of characteristic technologies suitable for overseas oil and gas fields have been created by combining the domestic mature oil and gas field production technologies with the features of overseas oil and gas reservoirs, represented by the technology for high-speed development and stabilizing oil production and controlling water rise for overseas sandstone oilfields, high efficiency development technology for large carbonate oil and gas reservoirs and foamy oil depletion development technology in use of horizontal wells for extra-heavy oil reservoirs. Based on in-depth analysis of the challenges faced by overseas oil and gas development and technological requirements, combined with the development trends of oil and gas development technologies in China and abroad, overseas oil and gas development technologies in the future are put forward, including artificial intelligence reservoir prediction and 3 D geological modeling, secondary development and enhanced oil recovery(EOR) of overseas sandstone oilfields after high speed development, water and gas injection to improve oil recovery in overseas carbonate oil and gas reservoirs, economic and effective development of overseas unconventional oil and gas reservoirs, efficient development of marine deep-water oil and gas reservoirs. The following goals are expected to be achieved: keep the enhanced oil recovery(EOR) technology for high water-cut sandstone oilfield at international advanced level, and make the development technology for carbonate oil and gas reservoirs reach the international advanced level, and the development technologies for unconventional and marine deep-water oil and gas reservoirs catch up the level of international leading oil companies quickly.

Analysis of the world oil and gas exploration situation in 2021

The global exploration investment, new oil and gas discoveries, exploration business adjustment strategies of oil companies in 2021, and future favorable exploration domains are systematically analyzed using commercial databases such as IHS and public information of oil companies. It has been found that the world oil and gas exploration situation in 2021 has continued the downturn since the outbreak of COVID-19. The investment and drilling workload decreased slightly, but the success rate of exploration wells, especially deepwater exploration wells, increased significantly, and the newly discovered reserves increased slightly compared with last year. Deep waters of the passive continental margin basins are still the leading sites for discovering conventional large and medium-sized oil and gas fields. The conventional oil and gas exploration in deep formations of onshore petroliferous basins has been keeping a good state, with tight/shale oil and gas discoveries made in Saudi Arabia, Russia, and other countries. While strengthening the exploration and development of local resources, national, international, and independent oil companies have been focusing on major overseas frontiers using their advantages, including risk exploration in deep waters and natural gas. Future favorable exploration directions in the three major frontiers, the global deep waters, deep onshore formations, and unconventional resources, have been clarified. Four suggestions are put forward for the global exploration business of Chinese oil companies: first, a farm in global deepwater frontier basins in advance through bidding at a low cost and adopt the “dual exploration model” after making large-scale discoveries;second, enter new blocks of emerging hot basins in the world through farm-in and other ways, to find large oil and gas fields quickly;third, cooperate with national oil companies of the resource host countries in the form of joint research and actively participate exploration of deep onshore formations of petroliferous basins;fourth, track tight/shale oil and gas cooperation opportunities in a few countries such as Saudi Arabia and Russia, and take advantage of mature domestic theories and technologies to farm in at an appropriate time.

Prediction of wax precipitation region in wellbore during deep water oil well testing

During deep water oil well testing, the low temperature environment is easy to cause wax precipitation, which affects the normal operation of the test and increases operating costs and risks. Therefore, a numerical method for predicting the wax precipitation region in oil strings was proposed based on the temperature and pressure fields of deep water test string and the wax precipitation calculation model. And the factors affecting the wax precipitation region were analyzed. The results show that: the wax precipitation region decreases with the increase of production rate, and increases with the decrease of geothermal gradient, increase of water depth and drop of water-cut of produced fluid, and increases slightly with the increase of formation pressure. Due to the effect of temperature and pressure fields, wax precipitation region is large in test strings at the beginning of well production. Wax precipitation region gradually increases with the increase of shut-in time. These conclusions can guide wax prevention during the testing of deep water oil well, to ensure the success of the test.

Hydrate Prevention Strategies and the Associated Cost in the Gulf of Mexico

With the petroleum industry endeavoring to develop promising oil and gas in deeper water, gas hydrates prevention is a serious concern for oil and gas producing companies producing at conditions in the hydrate region. This paper details lessons learned from the successful field deployment of AA LDHI and proper implementation strategies used for 3 different practical fields as case studies in the Gulf of Mexico. From the 3 field experiences, the AA LDHI has been used to replace the conventional thermodynamic hydrate inhibitor due to its numerous benefits during steady state operations and transition operations where AA LDHI is injected prior to extended shut in and restart for fields producing at low water cut. However, the strategy to develop a cost effective chemical management of hydrates for fields producing at high water cut is by pumping methanol or diesel to push down the wellbore fluid below the mud line during planned and unplanned shut-ins to delay water production, it also secures the riser with non hydrate fluids. This illustrates how the AA LDHIs are used in conjunction with more conventional hydrate management approaches to reach an optimal cost effective field hydrate management solution. However, this shows that the key to overall success of hydrate prevention is a full integration of a good front end design, a comprehensive deployment and an effective down hole monitoring system.

高精度油藏数值模拟技术研究进展及应用

受算力和油藏模拟方法的制约,常规油藏数值模拟技术的模拟规模和效率,难以满足中高渗老油田特高含水后期剩余油精准挖潜的需求,人工智能加速油藏模拟技术的应用仍处于初步应用阶段。“十四五”期间,大庆油田在大规模并行模拟技术、页岩油藏模拟技术研究、人工智能方法和油藏模拟技术应用4个方面开展了攻关。通过对分布式黑油油藏模拟网格求解方法和数据传输方式的改进,大规模并行模拟规模突破1亿节点;考虑页岩油藏微孔限域效应特征,研发了页岩油藏数值模拟软件;基于傅里叶神经算子神经网络,实现了油藏数值模拟的加速;应用数值模拟辅助历史拟合技术,结合物理模拟结果,建立聚合物相对渗透率曲线求取方法。分布式并行模拟技术的改进完善、页岩油藏模拟器的建立和人工智能方法的创新应用,为中高渗老油田剩余油挖潜和非常规油藏开发提供了技术保障。

中国油气勘探开发成就与未来潜力:深层、深水与非常规油气——专访中国科学院院士、石油地质与构造地质学家贾承造

中国石油工业上游取得了举世瞩目的成就:在资源困难条件下石油产量保持在年产量2×108 t水平,天然气产量快速增长,2022年天然气产量2200×108 m3,成为世界第4大产气国。塔里木盆地克拉2气田的发现是中国天然气勘探史的标志性成果,主要归功于对塔里木盆地构造性质和库车含油气系统的杰出研究和资源预测。中国的风险勘探工程、岩性地层油气藏勘探工程,以及国家科技重大专项“大型油气田及煤层气开发”极大地推动了中国油气勘探开发,提升了中国石油工业勘探开发科技水平,为中国油气产量增长作出了重大贡献。中国石油工业上游未来的发展潜力在深层、深水和非常规油气的勘探开发,以及老油气田提高采收率和CCS-CCUS业务。未来石油工业的发展将更多地依靠深层、深水与非常规油气地质理论技术的创新、钻井压裂和海洋工程施工能力的建设、更高效的组织管理能力和献身于中国石油工业的年轻一代。

时移地震技术在油藏监测中的应用 ——以西非深水扇A油田为例

A油田海上深水浊积砂岩油藏开发中井数少且井距大,井控程度较低,存在连通性难判断、水淹范围及程度难刻画、剩余油难预测等问题。时移地震技术基于分析不同时间点三维地震数据的波阻抗差异,可有效弥补井资料不足的问题,成为油田生产优化及调整挖潜的重要手段。以西非某典型深水扇油田为例,采用动静结合的思路,将时移地震与构造断裂、储层预测、井网分布、生产动态研究相结合,探讨时移地震在深水浊积挥发性油藏中的有效应用,为该类油田的时移地震应用提供借鉴与参考。研究表明,时移地震与断距结合,在判断断层封堵性方面具有较高的可靠性,可有效厘清开发矛盾,指导调整井的部署;时移地震与沉积相及储层预测相结合,可有效刻画出水驱前缘、表征水淹程度,明确生产优化方向;时移地震与井点泥岩隔夹层结合,可准确判断层间连通性,指导措施优化;综合构造断裂、沉积相分布、储层结构和井网等信息,可以实现对剩余油的有效预测并指导油田调整挖潜。

“深海一号”能源站开发模式关键技术研究与应用

为获得国内1500m水深区域的深水油气开发,国内展开了深水油气资源开发关键技术研究,在半潜式生产储油平台方面实现了重点技术突破和工程实践。“深海一号”能源站研究了“水下生产系统回接深水半潜式生产储油平台”开发模式,研究了半潜式生产储油平台母型船设计、半潜式生产储油平台陆地建造、钢悬链立管连接、聚酯缆系泊等关键技术,通过工程实践获得我国南海1500 m水域高产油气。该文对“深海一号”能源站“水下生产系统回接深水半潜式生产储油平台”开发模式进行了总结,并分析了“深海一号”开发模式下气田开发中后期水下生产系统升级的潜在需求,推动“深海一号”开发模式在南海深水、超深水油气开发中深入应用。

水下井口布置方式研究

水下开发是深水油气田的主要开发模式,并正逐步推广到部分浅水地区。水下井口布置方式及位置比选是开发方案中的重要部分,直接影响着油田开发的工程模式。本文系统研究了分散式、集中式这2种主要的水下井口布置形式,分析了应用条件及主要特点。基于多专业协同研究,形成了水下井口布置方案的关键考虑及分析流程,可为海上油气田水下井口布置提供参考。

全球海洋油气勘探开发状况与发展趋势

海洋油气勘探开发蓬勃发展,储量和产量不断攀升,在世界油气产量的比例不断增加,特别是深水油气勘探已成为世界石油工业新亮点。从油气资源及分布入手,文章详细介绍了全球海上油气资源勘探开发的基本状况,总结了国外海上油气勘探开发的基本经验,探讨了全球海洋油气勘探开发的发展趋势,并对促进我国海上油气勘探开发提出了一些建议和意见。

中国石油海外油气田开发技术进展与发展方向

通过系统回顾中国石油海外油气田开发技术的发展历程,总结已形成的特色开发技术,并针对海外油气开发面临的挑战,提出未来海外业务的发展目标与技术发展方向。中国石油经历海外20多年的油气田开发实践,将国内成熟油气田开发技术与海外油气藏特征相结合,形成了以海外砂岩油田高速开发及稳油控水技术、大型碳酸盐岩油气藏高效开发和超重油油藏整体水平井泡沫油冷采开发技术为代表的海外特色开发技术。在深入分析海外油气开发面临的挑战和技术需求的基础上,结合国内外油气开发技术发展趋势,提出未来海外油气开发技术需重点研发人工智能储集层预测与三维地质建模、海外砂岩油田高速开发后二次开发及提高采收率、海外碳酸盐岩油气藏注水注气提高采收率、海外非常规油气经济有效开发、海域深水油气藏高效开发配套技术等,实现海外高含水砂岩油田提高采收率技术继续保持国际领先,碳酸盐岩油气藏开发技术达到国际先进,非常规和海域深水油气开发技术逐步缩小差距,实现快速追赶等目标。

国外深水钢悬链线立管研究发展现状

介绍国外在新型深水立管系统——钢悬链线立管关键技术方面的研究发展现状,论述浮体一、二阶运动对钢悬链线立管疲劳寿命的影响、浮体升沉运动对钢悬链线立管触地点疲劳寿命的影响;钢悬链线立管与海底相互作用机制的实验研究及结果;钢悬链线立管涡致振动与疲劳的研究现状。并简要论述钢悬链线立管触地点问题的研究结论。

水玻璃凝胶增强泡沫体系的性能

对一种可用于强非均质油藏深部调剖的水玻璃凝胶泡沫体系的成胶特性、微观结构及在岩心中的封堵特性进行了研究。实验结果表明:盐酸与污泥的反应在密闭条件下是一个平衡反应,且其反应速度随初始压力的增加呈指数降低;体系的胶凝时间随着pH值的降低而增加。由于体系的泡径小,界面膜的强度高,因而水玻璃凝胶增强泡沫体系的封堵效果明显优于普通泡沫体系。

深水油井测试工况下井筒结蜡区域预测方法

针对深水油井测试过程中低温环境容易引起结蜡进而影响测试作业正常进行、增加作业成本和风险的问题,基于深水测试管柱温压场和析蜡条件计算模型,提出了测试管柱内结蜡区域预测方法,并对结蜡区域的影响因素进行了分析。研究表明:结蜡区域随着测试产量的增加而逐渐减小;随着地温梯度降低、水深增加及产出流体含水率降低,发生结蜡的区域会增大;随着地层压力的增加,结蜡区域略有增大;初开井阶段,由于温压场的共同作用,测试管柱内结蜡区域很大;循环测试关井后,随着关井时间的增加,结蜡区域逐渐增大。研究成果可为深水油井测试期间的井筒结蜡预防工作提供指导,以保证测试工作顺利进行。

水包油钻井液国内研究应用进展

对目前适合于深井欠平衡钻井作业的3类钻井液体系进行综合分析,从抗油、抗水侵能力、成本等角度出发,得出使用水包油钻井液体系最为合适,其配制方法简单,不需配备复杂设备,抗温能力强,流动性好,滤失量低,稳定井壁能力较强,抗水油侵能力强,润滑作用好,对储层伤害小,不影响电测和核磁测井,对环境污染小。文中对水包油钻井液体系的应用范围和基本组成,其乳状液的稳定机理,以及该体系的乳化剂使用特点进行了介绍,论述了近年来国内对该钻井液体系的研究应用现状,简要阐述了其可能的发展趋势。

高分辨率层序地层学在油田深度开发中的应用

根据钻井岩心、测井和成像测井等资料,综合研究了火烧山油田二叠系平地泉组H_2层不同级次基准面旋回界面和湖泛面的成因类型及高分辨率层序地层学特征,从H_2层(扇)三角洲沉积体系中划分出2个中期、8个短期旋回层序。讨论了短期旋回层序的沉积序列、结构类型、叠加样式和分布模式与储层非均质性、水淹特征和剩余油分布规律的关系,建立了以中期旋回层序和洪泛面为年代地层框架。以短期旋回层序为等时地层对比单元的地层格架,以短期旋回为等时编图单元,编制了H_2层沉积微相图。应用相控储层建模技术,以短期旋回层序为建模单元,建立了火烧山油田H_2层精细地质模型。研究结果表明,高分辨率层序地层学在高含水油田深度开发阶段有着广阔的应用前景。

全球海洋油气勘探开发特征及趋势分析

全球海洋油气资源潜力丰富,探明率较低,是未来重要资源储备基地。随着技术的发展,深水油气产量和新增储量占比不断攀升。国际石油公司加大深水油气布局,并不断努力降低深水油气成本,深水油气已具备明显的竞争力。未来,全球海洋油气的投资规模将持续扩大,并将步入数字化时代,海上风力发电与海洋油气的关系更加紧密,同时边际油田将在未来越来越受到关注。我国海洋油气发展面临机遇和调整,应积极快速参与到全球海洋油气勘探开发项目中去,获取更多海外优质资源;制定我国深水油气资源发展战略,提升深水油气勘探开发能力;加强资源整合,加快推进油气业务数字化转型;统筹规划海洋空间利用和能源资源统一开发,协同发展海洋油气和海上风力发电产业。

我国深水油气开发所面临的机遇与挑战

近几年,中国油企在进军海外市场中屡屡受挫,损失巨大。中国南海深水区有着丰富的油气资源。文章分析了世界深水油气发展的现状、趋势,研究了我国南海深水油气发展现状、所面临的困难及加快发展所面临的机遇,指出在当前全世界深水油气开发的浪潮中,在中国有30多年海上油气开发经验的积累下,中国已基本具备了加快深水油气开发的条件,中国应抓住发展机遇,迎接挑战,国家应在政策、资金、技术等方面加大投入,在深水油气开发中走出南海特色。