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.

Performance Evaluation of the Halophilic Crude Oildegrading Bacterial Consortium XH-1 for Oilfield Wastewater Treatment

A total of 14 halophilic hydrocarbon-degrading strains were isolated from crude oil-contaminated sites,using petroleum as the sole carbon and energy source.Among these,four highly efficient strains were selected to create the mixed bacterial agent XH-1.These four strains were identified through 16S rRNA gene-based sequencing as belonging to Acinetobacter,Bacillus paramycoides,Rhodococcus sp.,and Enterobacter sp.,respectively.The optimal cultivation time for the mixed consortium XH-1 was found to be 48 h,and a nitrogen-phosphorus molar ratio of 10:1 was determined to be beneficial for crude oil degradation.XH-1 showed notable crude oil degradation even at a salinity of up to 30 g/L,with little inhibition observed at sulfide concentrations as high as 150 mg/L and initial oil concentrations of 500 mg/L.Gas chromatography analysis revealed that XH-1 was able to efficiently degrade C9–C29 n-alkanes.Moreover,a bio-contact oxidation reactor enhanced by XH-1 showed promising results in treating oilfield wastewater.These findings suggest that XH-1 can be applied for the treatment of oilfield wastewater.

Oilfield analogy and productivity prediction based on machine learning: Field cases in PL oilfield, China

In the early time of oilfield development, insufficient production data and unclear understanding of oil production presented a challenge to reservoir engineers in devising effective development plans. To address this challenge, this study proposes a method using data mining technology to search for similar oil fields and predict well productivity. A query system of 135 analogy parameters is established based on geological and reservoir engineering research, and the weight values of these parameters are calculated using a data algorithm to establish an analogy system. The fuzzy matter-element algorithm is then used to calculate the similarity between oil fields, with fields having similarity greater than 70% identified as similar oil fields. Using similar oil fields as sample data, 8 important factors affecting well productivity are identified using the Pearson coefficient and mean decrease impurity(MDI) method. To establish productivity prediction models, linear regression(LR), random forest regression(RF), support vector regression(SVR), backpropagation(BP), extreme gradient boosting(XGBoost), and light gradient boosting machine(Light GBM) algorithms are used. Their performance is evaluated using the coefficient of determination(R^(2)), explained variance score(EV), mean squared error(MSE), and mean absolute error(MAE) metrics. The Light GBM model is selected to predict the productivity of 30 wells in the PL field with an average error of only 6.31%, which significantly improves the accuracy of the productivity prediction and meets the application requirements in the field. Finally, a software platform integrating data query,oil field analogy, productivity prediction, and knowledge base is established to identify patterns in massive reservoir development data and provide valuable technical references for new reservoir development.

Effect of CO_(2)flooding in an oil reservoir with strong bottom-water drive in the Tahe Oilfield,Tarim Basin,Northwest China

The dissolution and diffusion of CO_(2)in oil and water and its displacement mechanism were investigated by laboratory experiment and numerical simulation for Block 9 in the Tahe oilfield,a sandstone oil reservoir with strong bottom-water drive in Tarim Basin,Northwest China.Such parameters were analyzed as solubility ratio of CO_(2)in oil,gas and water,interfacial tension,in-situ oil viscosity distribution,remaining oil saturation distribution,and oil compositions.The results show that CO_(2)flooding could control water coning and increase oil production.In the early stage of the injection process,CO_(2)expanded vertically due to gravity differentiation,and extended laterally under the action of strong bottom water in the intermediate and late stages.The CO_(2)got enriched and extended at the oil-water interface,forming a high interfacial tension zone,which inhibited the coning of bottom water to some extent.A miscible region with low interfacial tension formed at the gas injection front,which reduced the in-situ oil viscosity by about 50%.The numerical simulation results show that enhanced oil recovery(EOR)is estimated at 5.72%and the oil exchange ratio of CO_(2)is 0.17 t/t.

Dynamic simulation of differential accumulation history of deep marine oil and gas in superimposed basin:A case study of Lower Paleozoic petroleum system of Tahe Oilfield,Tarim Basin,NW China

According to the complex differential accumulation history of deep marine oil and gas in superimposed basins,the Lower Paleozoic petroleum system in Tahe Oilfield of Tarim Basin is selected as a typical case,and the process of hydrocarbon generation and expulsion,migration and accumulation,adjustment and transformation of deep oil and gas is restored by means of reservoine-forming dynamics simulation.The thermal evolution history of the Lower Cambrian source rocks in Tahe Oilfield reflects the obvious differences in hydrocarbon generation and expulsion process and intensity in different tectonic zones,which is the main reason controlling the differences in deep oil and gas phases.The complex transport system composed of strike-slip fault and unconformity,etc.controlled early migration and accumulation and late adjustment of deep oil and gas,while the Middle Cambrian gypsum-salt rock in inner carbonate platform prevented vertical migration and accumulation of deep oil and gas,resulting in an obvious"fault-controlled"feature of deep oil and gas,in which the low potential area superimposed by the NE-strike-slip fault zone and deep oil and gas migration was conducive to accumulation,and it is mainly beaded along the strike-slip fault zone in the northeast direction.The dynamic simulation of reservoir formation reveals that the spatio-temporal configuration of"source-fault-fracture-gypsum-preservation"controls the differential accumulation of deep oil and gas in Tahe Oilfield.The Ordovician has experienced the accumulation history of multiple periods of charging,vertical migration and accumulation,and lateral adjustment and transformation,and deep oil and gas have always been in the dynamic equilibrium of migration,accumulation and escape.The statistics of residual oil and gas show that the deep stratum of Tahe Oilfield still has exploration and development potential in the Ordovician Yingshan Formation and Penglaiba Formation,and the Middle and Upper Cambrian ultra-deep stratum has a certain oil and gas resource prospect.This study provides a reference for the dynamic quantitative evaluation of deep oil and gas in the Tarim Basin,and also provides a reference for the study of reservoir formation and evolution in carbonate reservoir of paleo-craton basin.

低渗透老油田柔性侧钻水平井挖潜技术

针对低渗透老油田老井侧向深部剩余油气资源动用难度大的问题,形成了柔性侧钻水平井挖潜技术,并开展了现场试验。该技术首先采用柔性侧钻钻具在老井筒中实现低成本侧钻,然后采用水力喷射工艺诱导多条裂缝起裂,最后下入油管柱对侧钻井眼实施笼统多簇暂堵压裂,从而实现井间剩余储量的高效挖潜。该技术包含柔性侧钻水平井钻井和侧钻水平井压裂2项技术,前者主要涉及柔性钻杆结构和材料优化、钻进工艺、密闭取心工具3个方面,后者主要涉及压裂方案优化、压裂工具及实施工艺优化2个方面。该技术在长庆安塞油田开展了多轮现场试验,发现通过改变井型、缩小油水井排距,可以较好地建立压力驱替系统,实现压力的有效传导,从而达到低产低效井提液增产的目的,同时验证了该技术可为低渗透油藏剩余储量精准挖潜、储层精细动用提供有力支撑。

Petroleum Accumulation Associated with Volcanic Activity in the Tarim Basin —— Taking Tazhong-47 Oilfield as an Example

The discovery of the Tazhong-47 oilfield confirmed that it is realistic to explore oil and gas fields around igneous rocks in the Tarim basin. The favorable conditions for petroleum accumulation due to volcanic activity and igneous rocks formed during the activity show in two aspects. A) The contact surface of igneous rocks and the surrounding sedimentary rocks, like a vertical unconformity surface, formed the conduit of petroleum migration. Petroleum would accumulate once it encountered a trap in which the reservoir had fine porosity and permeability. B) It formed a trap barriered by igneous rocks, or changed or cut the original trap. In addition, volcanic rocks are a kind of potential reservoir, there are many such examples in the world, and oil also shows in the Permian igneous rocks in well Zhong-1 on Tazhong uplift. Petroleum accumulation associated with volcanic activity will be a new exploring field in the Tarim basin.

Application of Comprehensive Geophysical Techniques to Predict Carbonate Fractured Reservoirs inQingxi Oilfield

Inter-crystalline pores, cavities, and fractures created from diagenetic shrinkage of dolomite are inter-connected each other, forming fine oil- and gas-bearing reservoirs. It is hard to predict these complex fracture-cavity reservoirs because of their random distribution, different growth timing, and so on. Taking the lacustrine dolomite fracture-pore reservoir in the Lower Cretaceous Xiagou Formation in the Qingxi oilfield within the Jiuquan basin as an example, we put forward a comprehensive geophysical method to predict carbonate fractures.

顺北4号断裂带凝析气藏相态特征及差异富集主控因素

顺北4号断裂带位于顺托果勒低隆起中部,该条带油气藏类型为受断裂带控制的凝析气藏,内部凝析气藏相态特征具有明显的南北分异性,国内外同类型的油气藏较少,因此,对该条带的相态特征及造成其差异性分布的主控因素进行深入研究能为同类型凝析气藏的勘探开发提供借鉴。研究利用PVT(压力—容积—温度)高压物性实验分析、有机地球化学分析、流体包裹体分析测试等技术手段,综合研究得出相关认识。研究结果表明:顺北4号断裂带原油整体为低凝固点、低含硫、中—高含蜡的轻质油;天然气甲烷摩尔分数、气油比、天然气干燥系数、CO_(2)摩尔分数在段内呈现差异性分布特征;通过PVT实验分析油气藏类型为凝析气藏,地露压差较大,属于未饱和油藏,北段的临界温度、临界压力明显高于中、南段,由北向南存在递减趋势;从烃源岩和成藏的角度分析,认为顺北4号断裂带凝析气藏差异富集的主控因素为多源供烃和多期成藏。

气浮旋流中油滴与气泡的运动规律

微气泡气浮旋流技术是将气浮分离与旋流分离相结合的一种新型高效分离方法。利用微气泡气浮旋流技术进行油水分离,探究了溶气水微气泡、旋流场、絮凝剂3种因素对油水分离效果的影响,并用高速成像技术考察了微气泡与油滴、微气泡与絮体的结合过程。结果表明,溶气水微气泡可大幅缩短油水分离时间,相比纯水静置缩短了50%。在油水混合物初始质量浓度为400 mg/L时,气浮+旋流+絮凝剂组合工艺的最佳实验条件为油水混合物与溶气水的体积比1∶4、旋流速度370 r/min、复合絮凝剂(PAC∶CPAM)的复配比2∶1,此条件下污水最终含油质量浓度低于10 mg/L,满足《污水综合排放标准》(GB 8978—1996)。静水条件下,微气泡-絮体结合体的平均投影面积约为微气泡-油滴结合体的6倍,投加絮凝剂有利于提升油水分离效果。交互实验证明,相比纯水静置处理,经微气泡气浮、气浮+旋流以及气浮+旋流+絮凝剂3种工艺处理后,污水含油率分别降低38.7%、71.4%、76.5%。就最终油水分离效果来说,3因素组合>溶气水微气泡+旋流场>溶气水微气泡。

渤海B油田在线调剖乳液聚合物凝胶体系优选与应用

渤海B油田层非均质性日益严重,水驱指进现象严重,急需实施调剖作业用以延迟油层水淹速度和抑制油井含助剂提升。本文通过优选乳液聚合物、交联剂、交联助剂选出了成胶时间可调(2~9 d)、成胶强度可控(0.3×10^(4)~5×10^(4)mPa·s)的凝胶体系,具有“注得进、堵得住”的特点,成胶后封堵率可达到99%以上。该体系在渤海B油田C20H井组进行了矿场试验,调剖后井组综合含水率评价下降4.05%,日产油增加26.91 m3,效果显著。

生物纳米增注技术在渤海油田中低渗储层的应用

海上油田注入压力高,注水量达不到配注要求,为此研制了生物纳米增注技术,该技术主要由改性纳米颗粒和生物分散剂构成。文中利用红外光谱分析、扫描电镜观察等手段对生物纳米增注体系的分散稳定性、耐受性、粒径分布和改性接枝特性进行了评价。实验结果表明:生物纳米颗粒为疏水性纳米二氧化硅SiO2,不同加量的生物纳米溶液放置12~360 h后,透光率均保持在95%以上;生物纳米体系平均粒径为58.10 nm,Zeta电位维持在-32 mV左右,可抑制地层水矿化度的影响,最高抗矿化度为75 g/L。对生物纳米增注体系注入工艺参数进行了优化,结果表明:纳米溶液最佳加量为10%,最优注入量为3 PV,最佳注入速率为0.50 mL/min。渤海K油田进行了生物纳米增注技术矿场试验,3个月后,目标井作业后储层平均吸水指数由12 m^(3)/(d·MPa)升至30 m^(3)/(d·MPa),中低渗小层启动压力由15.1 MPa降至6.5 MPa,井组累计增注量已达0.9×10^(4) m^(3)。该研究为解决海上中低渗油藏注水困难以及保证油田发展提供了新技术、新思路。

砂质辫状河储集层构型表征——以孤东油田七区西馆陶组为例

孤东油田七区西馆陶组N1g45小层—N1g16小层为辫状河沉积,砂体内部构型复杂,需精细解剖储集层结构,揭示其对油气开发的影响。采用Miall构型要素分析法,以现代辫状河规模作为约束,进行砂体储集层构型表征,采用动静结合手段检验研究成果,总结储集层构型对注水开发和剩余油分布的影响。结果表明:研究区为砂质辫状河沉积,主要发育辫状河道、心滩、溢岸以及泛滥平原4种构型单元;辫流带宽度为150~750 m,宽厚比为47~74;在辫流带内,有辫状河道-辫状河道、心滩-心滩、辫状河道-心滩-辫状河道和心滩-辫状河道-心滩4类构型模式;心滩平均长度为250~350 m,平均宽度为110~140 m,长宽比为2.20~2.50,心滩与河道平面面积比为0.36~0.51;心滩内一般发育2~4个落淤层,落淤层延伸长度为70~150 m,产状近水平,背水面夹层倾角为0.9°~2.3°;生产动态揭示由于构型单元边部物性变差,构型拼接部位油气流动受阻,成为局部剩余油富集区;在构型单元主体部位,油藏连通性好,开发效果好。

纳米成膜封堵技术在塔里木油田的应用与研究

纳米成膜封堵技术是最前沿的钻井液防塌新技术,目前在塔里木油田井壁不稳定地层钻井过程中广泛应用。本文首先阐述了纳米成膜处理剂超微封堵原理,形成的封堵膜对疏水和减小压力传递作用起到良好防塌效果。其次,对粒径分布、封堵能力、泥岩理化性能、钻井液性能进行室内研究,120 min砂床滤失量降低率92.42%,封堵作用明显,填补纳米级封堵空白。最后,列举了纳米成膜防塌技术在塔里木油田现场应用效果,成功解决了井下垮塌问题。本文旨在为不同区域油气钻井过程提供纳米成膜封堵技术理论和应用参考。

翻译四步骤理论指导下石油科技文本的机译问题与对策--以Oilfield Review的节译为例

随着待翻译文本涉及的领域越来越广、翻译量越来越大,机器翻译因其具有速度快、价格低廉的特点逐渐成为重要的翻译手段。此后,机器翻译与译者的关系一直受到学者们的关注。文章以乔治斯坦纳提出的翻译四步骤作为指导,将Oilfield Review中的部分内容作为源文本,使用谷歌翻译将原内容转换成中文,后从理论内容中信赖、侵入、吸收、补偿的四个方面分析机器翻译后的石油科技文本出现的问题,并提供解决方案。

注入生产水对储层岩心的堵塞机理及配伍性评价

以中国南海西部某油田为例,综合考察了生产水中悬浮颗粒、油、化学离子等因素对油田储层岩心堵塞的影响。结果表明,注入水驱替体积越多,级别越低的岩心渗透率伤害程度越高。随着岩心级别的增加,化学堵塞对岩心的伤害程度逐级递减,100 m D以下级别的岩心伤害率均超过20%。10~50 mD、50~100 mD、100~300 mD三种级别的岩心在不同平台中物理因素对岩心堵塞贡献分别是化学因素贡献占比的6.45、14.89、6.67、3.15倍。两块相同级别的天然岩心与人造岩心在经过驱替后渗透率保留率相差不大,说明了注入流体与岩石配伍性良好,但长期水驱对岩心(尤其是低渗岩心)的伤害较大。

雷电保护装置在油田电力线路上的应用

随着油田生产建设不断发展,电力配电网络的运行可靠性、安全性越来越受到重视。作为电力配电网络主要组成部分的10(6)kV配电线路,由于长期在空旷的野外运行,当遇到雷雨天气时,极易遭受到雷击,导致电力线路经常跳闸断电,甚至引发绝缘子击穿、导线烧毁等事故发生,还会因停电导致大批机采井停产,给油田生产造成了巨大的经济损失。通过针对雷电对架空电力线路造成的各种危害原因进行调查、分析、统计和研究,结合油田地理环境的特点,提出了一种新的设计思路,改变以往防直击雷为主的传统的设计理念,采用以防感应雷为主、防直击雷为辅的防雷方案。经多方调研论证,在边远容易落雷地区的架空电力线路上,设计了国内新型的多腔吹弧式雷电保护装置,其技术先进、结构合理、性能优越,具有工频续流遮断能力,既能防直击雷又能防感应雷。正常运行时,避雷装置的空气间隙可与电力线路脱离,当雷电作用在线路上时,可短暂建弧释放电流,不跳闸、不断电,既消除了雷电对电力线路的危害,又能确保电力线路在雷电天气安全、可靠运行。

Using a support vector machine method to predict the development indices of very high water cut oilfields

Because the oilfields in eastern China are in the very high water cut development stage, accurate forecast of oilfield development indices is important for exploiting the oilfields efficiently. Regarding the problems of the small number of samples collected for oilfield development indices, a new support vector regression prediction method for development indices is proposed in this paper. This method uses the principle of functional simulation to determine the input-output of a support vector machine prediction system based on historical oilfield development data. It chooses the kernel function of the support vector machine by analyzing time series characteristics of the development index; trains and tests the support vector machine network with historical data to construct the support vector regression prediction model of oilfield development indices; and predicts the development index. The case study shows that the proposed method is feasible, and predicted development indices agree well with the development performance of very high water cut oilfields.

油田后勤党支部开展党建工作的做法及下步对策建议

后勤服务党支部(简称“党支部”)作为采油厂后勤服务的重要组成部分,积极响应厂党委的号召,开展了一系列党建工作,取得了一定的成效。文章分析了后勤党支部作为采油厂后勤服务重要组成部分的现状和存在的问题,包括党建质量不高、支部委员党建履职能力有待加强等方面。针对这些问题,文章提出了强化政治建设、加强支部委员党建履职能力加强党建工作与业务工作融合等六方面具体思路和措施,以进一步推动后勤服务的发展和提升,确保党支部工作有效贯彻党委决策部署,为采油厂后勤服务的高质量发展提供有力组织保障。

Burial Dissolution of Ordovician Granule Limestone in the Tahe Oilfield of the Tarim Basin,NW China,and Its Geological Significance

With a comprehensive study on the petrology, geology and geochemistry of some Ordovician granule limestone samples in the Tahe Oiifieid of the Tarim Basin, two stages of burial dissolution were put forward as an in-source dissolution and out-source dissolution based on macro-microcosmic petrology and geochemistry features. The main differences in the two stages are in the origin and moving pass of acid fluids. Geochemical evidence indicates that burial dissolution fluids might be ingredients of organic acids, CO2 and H2S associated with organic matter maturation and hydrocarbon decomposition, and the in-source fluid came from organic matter in the granule limestone itself, but the out-source was mainly from other argillaceous carbonate rocks far away. So, the forming of a burial dissolution reservoir resulted from both in-source and the out-source dissolutions. The granule limestone firstly formed unattached pinholes under in-source dissolution in situ, and afterwards suffered wider dissolution with out-source fluids moving along unconformities, seams, faults and associate fissures. The second stage was much more important, and the mineral composition in the stratum and heat convection of the fluid were also important in forming favorable reservoirs.