吴410区长6油藏开发特征及储层攻关技术对策

针对吴410区长6油藏投入开发以来,开发初期表现出的单井产量递减快、产能低、水驱效果差等问题,通过近几年现场攻关试验,主要从油藏动态监测方法、井网适应性研究等方面认识油藏,形成了一套有效开发超低渗透油田的主要技术对策,对改善同类油田的开发效果具有借鉴意义。     

濮城油田沙一段油藏濮1—1井组二氧化碳驱研究及先导试验效果分析

根据沙一油藏的物性特点，开展了CO2驱研究，室内进行了地层原油相态、压力组分、注CO2压力等实验。为了确定合理的开采方式，进行了连续注CO2、水气交替注入等实验研究。室内实验表明，在沙一油藏进行CO2驱是可行的。在室内模拟和CO2驱替实验的基础上，在现场开展了矿场试验。通过在濮1—1井进行试验，井组取得了好的效果，日增油8．5t，累积增油1150t。这为下步濮城油田高含水油藏进一步提高采收率提供了新的途径。     

西峰油田酸化增产技术研究与应用

针对西峰油田长8油藏低渗、细孔喉、砂岩泥质含量高等储层特点，分析了储层堵塞的原因，通过理论及试验优化出了本区块酸化增产的酸液配方。使用土酸酸化角井成功率相对较高，边井成功率低，复合有机酸酸化增产技术从应用效果看好于土酸酸化，为该地区措施提高单井产量积累了一定宝贵经验。     

聚合物驱在渤海旅大10—1油田的应用

海上油田开发具有勘探投入大、采油平台使用寿命短、生产操作费用高和水驱采收率低等特点，如何提高采收率是油田开发面临的重大技术难题。从海上油田LD10—1开发实际需求出发，结合油藏地质特征和流体性质特点，利用理论分析和室内评价实验，开展了早期聚合物凝胶和聚合物驱增油效果及其影响因素实验研究。结果表明，早期实施聚合物驱不仅大大缩短油田开发时间、节省操作费用，而且最终采收率也比中后期实施时高。在化学药剂费用相同条件下，“聚合物凝胶＋聚合物”段塞组合驱的增油效果要好于单纯聚合物驱。A23井单井组聚合物驱矿场试验于2006年3月23日开始，矿场监测结果表明，注入压力大幅度提高，吸液剖面明显改善，部分油井已陆续见到“增油降水”效果。     

濮城油田沙三中6-10油藏活性纳米粉体降压增注技术研究

濮城油田沙三中6-10油藏为低渗油藏,因注入水质差,造成对地层的伤害,注水压力不断上升。通过分析造成地层伤害的主要因素,为控制注水压力的上升,提出了活性纳米降压增注技术,并在室内进行了研究,从活性材料选择、表面修饰剂选择、分散介质选择以及纳米粉体水分散最佳浓度进行了室内筛选,指出了纳米酸化技术的可行性。在室内研究的基础上,在现场开展了10口井活性纳米技术的应用,取得了良好的效果。     

海上油田泡沫堵水技术研究与应用

如何有效地实现控水增油是目前海上油田进行高效高速开发所面临的问题。泡沫堵水技术作为一项控水增油的增产工艺措施在陆上油田得到了成功的应用,且近年来泡沫设备的改进使得该技术在海上油田的应用成为可能。此文通过泡沫静态实验、动态实验优选出了适合目标油藏条件的高效起泡剂,并对泡沫的油敏性,封堵能力,提高采收率性能进行了研究。实验结果表明,筛选出的起泡剂就有较好的起泡性能,泡沫具有较好的堵水效果,堵水率最高达到97．8％,且对高渗模型提高采收率幅度达到15．9％。通过在海上油田的应用,该技术实现了控水增油的作用,取得了较好的增产效果。     

冀东油田高浅北地区交联聚合物调驱适应性评价

冀东油田G104-5区块浅层油藏储层胶结疏松,边底水活跃,随着采液速度的提高,边水沿高渗透带突进,油井含水上升速度快,油藏的复杂性给调剖调驱工艺带来一定难度。针对冀东油田地质和开发情况,通过深入分析、研究,在大量室内物模的基础上筛选研制了一种适合冀东油田浅层油藏调驱的交联聚合物体系并应用到现场,取得了良好的降水增油效果,两年来累计增油4.4×104t,有效地控制了该区块边水推进速度,改善了开发效果,为冀东油田夺油上产提供了技术保障,同时为其它浅层油藏区块提高原油采收率提供技术方法和参考依据。     

江苏油田真12断块E2s16储层特征及剩余油分布

真12断块E2s1^6是真武油田主力开发层系，以岩心、测井、生产动态资料为基础，通过流动单元、隔夹层、渗透率韵律类型等，研究与渗透率变化有关的储层非均质性，建立储层物性参数模型，通过油藏数模模拟两类剖面和建立不同含水期集层渗透率模型，研究油藏纵向油水运动规律，研究剩余油分布，为E2s1^6油藏最终提高采收率、改善开发效果提供依据。     

海上“薄散弱”油藏有效开发实践

“薄散弱”油藏由于其油层薄、砂体小、分布零散、天然能量弱,采用定向井难以经济有效开发;采用水平井开发虽可提高单井初期产量,但由于地层能量不足,产量递减快,无法从根本上解决采收率低的问题;注水开发虽能解决地层能量不足问题,但海上注水要增加设备、平台空间及平台重量,相应地增加开发成本,加上其储量规模小,经济效益难以保证.以X油田H4油藏为例,在储层精细描述的基础上,提出并实践了多底多分支水平井技术与地层自流注水技术,实现了“薄散弱”油藏的经济有效开发,并取得了较好的开发效果.其实践成果对类似难动用储量的经济有效开发具有借鉴和参考意义.     

海上埕岛油田馆上段提液技术政策研究

针对目前胜利油区埕岛油田单井液量低、产油量低的问题展开提高采液量研究。应用油藏工程和数值模拟等方法，研究了该油藏的提液潜力和适合该油藏的提液时机及提液条件。研究结果表明：油藏具备提液的潜力和提液条件，在含水达到70％～80％时提液效果最佳，提液条件是恢复地层压力到原始压力的0．85倍，恢复压力的最佳注采比为1．1，提液最大生产压差为3．5MPa。矿场应用取得了提液增油的明显效果，对海上同类型油田提高注水开发效果具有积极的指导意义。     

鄂尔多斯盆地王窑地区上三叠统长6油层成岩作用研究

通过多项测试方法，对安塞油田王窑地区长6油层含油砂体的岩石学、成岩作用、储集物性和孔隙发育特征进行分析和研究。结果表明，该区储集砂体为成分成熟度较低的长石砂岩；主要自生矿物为绿泥石、浊沸石、方解石、石英、钾长石、伊利石和钠长石等；储层次生孔隙发育，主要孔隙类型为粒间孔隙、骨架颗粒溶孔和浊沸石溶孔。孔隙结构具有小孔、细喉的特点；储层成岩演化阶段处于晚成岩A亚期；储层性质明显地受到沉积微相和成岩作用的影响。沉积物粒度较粗、厚度较大的河道砂和河口砂坝砂的储集物性明显优于各种粒度较细、厚度较薄的席状砂体。     

Quantitative impact of diagenesis on reservoir quality of the Triassic Chang 6 tight oil sandstones,Zhenjing area,Ordos Basin,China

The Upper Triassic Chang 6 sandstone, an important exploration target in the Ordos Basin, is a typical tight oil reservoir. Reservoir quality is a critical factor for tight oil exploration. Based on thin sections, scanning electron microscopy (SEM), X-ray diffraction (XRD), stable isotopes, and fluid inclusions, the diagenetic processes and their impact on the reservoir quality of the Chang 6 sandstones in the Zhenjing area were quantitatively analysed. The initial porosity of the Chang 6 sandstones is 39.2%, as calculated from point counting and grain size analysis. Mechanical and chemical compaction are the dominant processes for the destruction of pore spaces, leading to a porosity reduction of 14.2%–20.2% during progressive burial. The porosity continually decreased from 4.3% to 12.4% due to carbonate cementation, quartz overgrowth and clay mineral precipitation. Diagenetic processes were influenced by grain size, sorting and mineral compositions. Evaluation of petrographic observations indicates that different extents of compaction and calcite cementation are responsible for the formation of high-porosity and low-porosity reservoirs. Secondary porosity formed due to the burial dissolution of feldspar, rock fragments and laumontite in the Chang 6 sandstones. However, in a relatively closed geochemical system, products of dissolution cannot be transported away over a long distance. As a result, they precipitated in nearby pores and pore throats. In addition, quantitative calculations showed that the dissolution and associated precipitation of products of dissolution were nearly balanced. Consequently, the total porosity of the Chang 6 sandstones increased slightly due to burial dissolution, but the permeability decreased significantly because of the occlusion of pore throats by the dissolution-associated precipitation of authigenic minerals. Therefore, the limited increase in net-porosity from dissolution, combined with intense compaction and cementation, account for the low permeability and strong heterogeneity in the Chang 6 sandstones in the Zhenjing area.     

Controls on reservoir heterogeneity of tight sand oil reservoirs in Upper Triassic Yanchang Formation in Longdong Area,southwest Ordos Basin,China: Implications for reservoir quality prediction and oil accumulation

Compared to conventional reservoirs, pore structure and diagenetic alterations of unconventional tight sand oil reservoirs are highly heterogeneous. The Upper Triassic Yanchang Formation is a major tight-oil-bearing formation in the Ordos Basin, providing an opportunity to study the factors that control reservoir heterogeneity and the heterogeneity of oil accumulation in tight oil sandstones.The Chang 8 tight oil sandstone in the study area is comprised of fine-to medium-grained, moderately to well-sorted lithic arkose and feldspathic litharenite. The reservoir quality is extremely heterogeneous due to large heterogeneities in the depositional facies, pore structures and diagenetic alterations. Small throat size is believed to be responsible for the ultra-low permeability in tight oil reservoirs. Most reservoirs with good reservoir quality, larger pore-throat size, lower pore-throat radius ratio and well pore connectivity were deposited in high-energy environments, such as distributary channels and mouth bars. For a given depositional facies, reservoir quality varies with the bedding structures. Massive- or parallel-bedded sandstones are more favorable for the development of porosity and permeability sweet zones for oil charging and accumulation than cross-bedded sandstones.Authigenic chlorite rim cementation and dissolution of unstable detrital grains are two major diagenetic processes that preserve porosity and permeability sweet zones in oil-bearing intervals. Nevertheless, chlorite rims cannot effectively preserve porosity-permeability when the chlorite content is greater than a threshold value of 7%, and compaction played a minor role in porosity destruction in the situation. Intensive cementation of pore-lining chlorites significantly reduces reservoir permeability by obstructing the pore-throats and reducing their connectivity. Stratigraphically, sandstones within 1 m from adjacent sandstone-mudstone contacts are usually tightly cemented (carbonate cement > 10%) with low porosity and permeability (lower than 10% and 0.1 mD, respectively). The carbonate cement most likely originates from external sources, probably derived from the surrounding mudstone. Most late carbonate cements filled the previously dissolved intra-feldspar pores and the residual intergranular pores, and finally formed the tight reservoirs.The petrophysical properties significantly control the fluid flow capability and the oil charging/accumulation capability of the Chang 8 tight sandstones. Oil layers usually have oil saturation greater than 40%. A pore-throat radius of less than 0.4 μm is not effective for producible oil to flow, and the cut off of porosity and permeability for the net pay are 7% and 0.1 mD, respectively.     

Numerical simulation of hydrocarbon migration in tight reservoir based on Artificial Immune Ant Colony Algorithm: A case of the Chang 81 reservoir of the Triassic Yanchang Formation in the Huaqing area,Ordos Basin,China

The hydrocarbon migration in tight reservoirs is a complex process, the fluid flow patterns of which are notably different from those of conventional reservoirs. Therefore, specific mathematical models are needed to simulate the secondary hydrocarbon migrations. This study presents a numerical simulation method based on Artificial Immune Ant Colony Algorithm (AIACA) to simulate the secondary hydrocarbon migrations in tight reservoirs. It consists of three core parts: (1) the release modes of artificial ants based on the intensity of hydrocarbon generation; (2) the wandering patterns of artificial ants under the control of the dynamic field and the distribution of pheromones; (3) the updating modes of pheromones based on the changes in reservoir wettability. The simulation of secondary migration can be realized by the observing the dynamic movements and accumulations of the artificial ants. The method has been tested in the Chang 8₁ tight sandstone reservoir, which is part of the Triassic Yanchang Formation in the Huaqing Area, Ordos Basin in China, and proved to be successful in matching the current data in exploration and development.     

高平4水平井组双保钻井液技术

高平4井组水平井主要用于开发安塞长10组油藏。针对该井组上部直罗组和富县组易坍塌、下部地层钻速相对较慢、地层易造浆的特点，研究应用了环保型聚硅酸盐-黄胞胶钻井液体系。该体系具有抑制性强、润滑和剪切稀释性好的特点，有利于安全快速钻井，对环境污染极小。通过小型配浆实验确定钻井液施工方案，中测后稀释钻井液，降低钻井液滤失量和密度，加强固相控制，使用保护油层的酸溶性暂堵剂和降滤失剂，可最大限度地保护油层。     

滩海油田开发初期的地质建模研究

地质建模是油田开发的基础性工作,由于滩海油田特殊的地理位置条件,造成钻井少,各种资料获取、采集难度大,给处于开发初期的油田带来了较大挑战。以大港滩海关家堡开发区为例,提出在前期地质概念模型的指导下,多学科综合,应用随机模拟理论,采用储层约束反演与地质建模相结合,建立储层岩性模型,并在岩性模型的控制下实现储层参数建模,通过三维地质模型的建立,提取出沿设计井轨迹方向的预测曲线成果,指导复杂结构井的钻探,利用该建模思路与成果,大大降低了井间储层预测的不确定性与开发风险,现场实施效果显著,其建模方法对于类似滩海稀井网开发提供了很好的借鉴。     

Impact of diagenesis on reservoir quality and heterogeneity of the Upper Triassic Chang 8 tight oil sandstones in the Zhenjing area,Ordos Basin,China

Reservoir quality and heterogeneity are critical risk factors in tight oil exploration. The integrated, analysis of the petrographic characteristics and the types and distribution of diagenetic alterations in the Chang 8 sandstones from the Zhenjing area using core, log, thin-section, SEM, petrophysical and stable isotopic data provides insight into the factors responsible for variations in porosity and permeability in tight sandstones. The results indicate that the Chang 8 sandstones mainly from subaqueous distributary channel facies are mostly moderately well to well sorted fine-grained feldspathic litharenites and lithic arkose. The sandstones have ultra-low permeabilities that are commonly less than 1 mD, a wide range of porosities from 0.3 to 18.1%, and two distinct porosity-permeability trends with a boundary of approximately 10% porosity. These petrophysical features are closely related to the types and distribution of the diagenetic alterations. Compaction is a regional porosity-reducing process that was responsible for a loss of more than half of the original porosity in nearly all of the samples. The wide range of porosity is attributed to variations in calcite cementation and chlorite coatings. The relatively high-porosity reservoirs formed due to preservation of the primary intergranular pores by chlorite coatings rather than burial dissolution; however, the chlorites also obstruct pore throats, which lead to the development of reservoirs with high porosity but low permeability. In contrast, calcite cementation is the dominant factor in the formation of low-porosity, ultra-low-permeability reservoirs by filling both the primary pores and the pore throats in the sandstones. The eogenetic calcites are commonly concentrated in tightly cemented concretions or layers adjacent to sandstone-mudstone contacts, while the mesogenetic calcites were deposited in all of the intervals and led to further heterogeneity. This study can be used as an analogue to understand the variations in the pathways of diagenetic evolution and their impacts on the reservoir quality and heterogeneity of sandstones and is useful for predicting the distribution of potential high-quality reservoirs in similar geological settings.     

济阳坳陷成熟探区探井失利地质原因分析

胜利油田经过近40多年的勘探，按照国内外勘探程度划分的标准，其主力探区济阳坳陷目前已处于成熟勘探程度，全面进入隐蔽油气藏勘探阶段，勘探难度越来越大。尽管济阳坳陷探井成功率保持较高的水平，但仍有50％左右的探井落空或低效。根据“失利”探井定义，从生、储、盖、图、运、保等6种油气成藏控制因素出发，参考济阳坳陷石油地质特点和近几年的勘探经验，主要从圈闭是否有效、储层是否存在、输导体系是否发育、油气充满程度等4个方面进行失利探井地质原因分析，建立起成熟探区探井失利地质原因分析方法。总结了济阳坳陷“十五”以来主要增储目标，即：砂砾岩体、浊积砂体、滩坝砂体、河道砂体等储层类型的失利地质原因。在明确上述目标类型最主要勘探风险的基础上，提出了勘探攻关重点及风险规避建议。