Kinetic studies on extra heavy crude oil upgrading using nanocatalysts by applying CFD techniques

Regarding the growth of global energy consumption and the paucity of light crude oil, extracting and using heavy and extra heavy crude oil has received much more attention, but the application of this kind of oil is complicated due to its very high molecular weight. High viscosity and low flowability complicate the transportation of heavy and extra heavy crude oil. Accordingly, it is essential to reduce the viscosity of heavy and extra heavy crude oil through in-situ operations or immediate actions after extraction to reduce costs. Numerical simulations are influential methods, because they reduce calculation time and costs. In this study, the cracking of extra heavy crude oil using computational fluid dynamics is simulated, and a unique kinetic model is proposed based on experimental procedures to predict the behavior of extra heavy crude oil cracking reaction. Moreover, the hydrodynamics and heat transfer of the system and influence of nanocatalysts and temperature on the upgrading of crude oil are studied. The geometry of a reactor is produced using commercial software, and some experiments are performed to examine the validity and accuracy of the numerical results. The findings reveal that there is a good agreement between the numerical and experimental results. Furthermore, to investigate the main factors affecting the process, sensitivity analysis is adopted. Results show that type of catalyst and concentration of catalyst are the parameters that influence the viscosity reduction of extra heavy crude oil the most. The findings further revealed that when using a 25 nm SiO_2 nanocatalyst, a maximum viscosity reduction of 98.67% is observed at 623 K. Also, a catalyst concentration of 2.28 wt% is best for upgrading extra heavy crude oil. The results obtained through sensitivity analysis, simulation model, and experiments represent effectual information for the design and development of high performance upgrading processes for energy applications.

纳米N-A降黏剂的制备及性能评价

针对普通纳米降黏剂对特稠油降黏效果差、洗油效率低等问题,制备了纳米N-A降黏剂,采用FTIR,TEM等方法表征了降黏剂的微观结构,考察了降黏剂的降黏效果、界面张力以及洗油效率。实验结果表明,纳米N-A降黏剂组成为:50%(w)纳米二氧化硅溶胶+40%(w)分散剂EB-1+4.2%(w)表面修饰剂+5.8%(w)增效剂。该降黏剂分散性能良好,粒径分布在20~60 nm之间,在降黏剂含量为1%(w)、油水质量比为7∶3、200℃,矿化度为0,8829.26 mg/L条件下老化48 h,特稠油降黏后黏度分别为6280,7213 mPa·s,降黏率分别达到83.77%,81.36%,降黏性能保持率分别为96.80%,95.39%。50℃下静置90 d后降黏性能保持率大于90%,可降低油水界面张力至0.076 mN/m,乳化液滴最大粒径9.5μm,洗油效率为30.9%,相对普通降黏剂,驱油效率提高22.3百分点。

A parametric study of the hydrodynamic roughness produced by a wall coating layer of heavy oil

In water-lubricated pipeline transportation of heavy oil and bitumen, a thin oil film typically coats the pipe wall. A detailed study of the hydrodynamic effects of this fouling layer is critical to the design and operation of oil-water pipelines, as it can increase the pipeline pressure loss （and pumping power requirements） by 15 times or more. In this study, a parametric investigation of the hydrodynamic effects caused by the wall coating of viscous oil was conducted. A custom-built rectangular flow cell was used. A validated CFD-based procedure was used to determine the hydrodynamic roughness from the measured pressure losses. A similar procedure was followed for a set of pipe loop tests. The effects of the thickness of the oil coating layer, the oil viscosity, and water flow rate on the hydrodynamic roughness were evaluated. Oil viscosities from 3 to 21300 Pa s were tested. The results show that the equivalent hydrodynamic roughness produced by a wall coating layer of viscous oil is dependent on the coating thickness but essentially independent of oil viscosity. A new correlation was developed using these data to predict the hydrodynamic roughness for flow conditions in which a viscous oil coating is produced on the pipe wall.

超稠油直井-水平井组合蒸汽辅助重力泄油物理和数值模拟

研究了中深层超稠油油藏在直井蒸汽吞吐中后期,用直井注汽水平井采油的方式转蒸汽辅助重力泄油(steam as-sisted gravity drainage,SAGD)开发的机理。应用高温高压比例物理模拟方法,研究了水平井布于直井斜下方时SAGD蒸汽腔的形成和扩展过程。结果表明,转SAGD的初期以蒸汽驱动作用为主并逐步向重力泄油作用过渡,并可划分为蒸汽吞吐预热、驱替泄油、稳定泄油、衰竭开采4个开采阶段。利用数值模拟优选了布井方式、井网井距、水平井段长度、转SAGD时机和注采参数。该模拟方法在辽河油田杜84块超稠油油藏开发中取得了较好的现场试验效果。

表面活性剂复配体系BS-9在稠油乳化降黏中的应用性能研究

BS-9为聚氧乙烯(20)鲸蜡醇醚与十二烷基硫酸钠及助剂的混合物,由表面张力曲线测得蒸馏水溶液25℃下临界胶束浓度为7×10-5mol/L。黏度(50℃)24.1Pa.s的胜利陈庄特稠油与0.1%的BS-9蒸馏水溶液以体积比8∶2、7∶3、6∶4、5∶5混合形成的乳状液,其黏度比稠油降低73.03%、87.55%、89.13%、80.17%,静置1小时后(50℃)脱水率为82%、96%、88%、98%;当BS-9质量分数增至0.15%,油水体积比为7∶3和6∶4时,稠油乳化降黏率大幅增至96.31%和98.22%,静置1小时脱水率则有所减小(73%和60%),用含Ca2+、Mg2+各0.2g/L、矿化度10g/L的矿化水配制的0.1%BS-9溶液,在油水体积比为8∶2、7∶3、6∶4、5∶5时对稠油的乳化降黏率与0.1%BS-9蒸馏水溶基本相同;BS-9在矿化水溶液中的质量分数增至0.15%时,除油水体积比8∶2时对稠油的乳化降黏率有所增大外,乳化降黏效果并无改善。BS-9溶液逐步加热至90℃未见浑浊。BS-9可用于高矿化度、高钙镁条件下稠油的乳化降黏开采。

特稠油-水两相水平管流压降规律研究

针对特稠油高黏及其组成复杂特性造成的集输难题,以新疆K96井区特稠油和自来水为研究对象,在混合流速为0.4~1.5m·s-1、入口含水率为0.5~0.8、温度为60~85℃的试验条件下,环道模拟了特稠油-水两相水平管流阻力特性,分析了入口含水率、混合流速和温度对特稠油-水两相水平管流压降的影响。结果表明：特稠油-水两相管流转相点为0.55,含水率高于转相点20%左右时,油水两相流的流动性良好,其压降梯度对混合流速和温度不敏感;而低于此值时则不然,压降梯度随混合流速和温度的波动较大。研究为特稠油或超稠油掺水安全经济集输提供了参考。

浅层超稠油热采杜84-平28井设计与实钻技术

曙一区杜84块是辽河油田超稠油难采储量中规模较大的具有代表性的区块,开发中存在注汽困难、生产周期短、油井作业频繁热损失大、地层普遍出砂、综合成本高、开采难度大等一系列问题。根据油藏生产动态和综合分析油藏地质参数,结合油藏特征及原井网开发状况,通过对杜84-平28井优化设计和精心组织施工,重点对施工中产生的主要问题进行分析,采取科学合理的技术措施,取得显著的开发效果。

超稠油采出液预脱水剂PDB-Ⅱ研制与应用

以辽河油田杜84块馆陶油层SAGD采出液为研究对象,研制出一种具有较强适用性的预脱水剂PDB-Ⅱ。室内实验显示该预脱水剂具有良好的油水分离效果,与破乳剂有良好的协同效应,在温度为150-160℃、加入量为300 mg/L、作用时间为3 h的条件下,可使处理后的采出液净化油含水达到低于20%、污水含油低于5 000 mg/L的预期效果。预脱水剂PDB-Ⅱ已成功应用于SAGD中试试验站,现场应用该预脱水剂试验结果表明,在与室内实验温度、加入量、作用时间同等条件下可使净化油含水低于10%,污水含油低于5 000 mg/L,可满足生产设计要求。该预脱水剂的研制成功填补了该领域国内空白,对SAGD技术的大规模推广具有极其重要的意义。

辽东湾坳陷新近系特稠油成藏模式与成藏过程——以旅大5-2北油田为例

辽东湾坳陷断裂构造带原油稠化作用强烈,形成了复杂的特稠油油藏,其特殊的油藏模式为勘探阶段的油藏评价带来巨大风险。基于测井资料、岩心和薄片观察结果、原油地化分析和包裹体测温等技术,建立了旅大5-2北油田特稠油油藏模式,并对其成藏过程进行研究。结果表明:明化镇组和馆陶组特稠油藏与常规油藏相比具有不统一的油-水界面、弧形的油藏边界、油-水关系倒置以及油顶为分选极差的砂砾岩等特征;在距今约25 Ma东营组沉积末期,来自辽中凹陷和辽西南洼的原油在东营组经历了第一期成藏,由于处于断裂带且埋深较浅,原油遭初步的生物降解作用;自明化镇组沉积期距今5 Ma以来,东营组聚集原油遭受破坏,沿控圈断层作垂向运移至浅层,受早期稠化作用的影响,一方面在很大程度上降低了对保存条件的要求,原油可以在盖层条件较差的储层中聚集成藏,另一方面原油优先选择物性较好的储层进行充注,伴随着聚集后进一步强烈的生物降解作用,形成特殊的油藏模式。

Diffusion coefficients of natural gas in foamy oil systems under high pressures

The diffusion coefficient of natural gas in foamy oil is one of the key parameters to evaluate the feasibility of gas injection for enhanced oil recovery in foamy oil reservoirs. In this paper, a PVT cell was used to measure diffusion coefficients of natural gas in Venezuela foamy oil at high pressures, and a new method for deter- mining the diffusion coefficient in the foamy oil was de- veloped on the basis of experimental data. The effects of pressure and the types of the liquid phase on the diffusion coefficient of the natural gas were discussed. The results indicate that the diffusion coefficients of natural gas in foamy oil, saturated oil, and dead oil increase linearly with increasing pressure. The diffusion coefficient of natural gas in the foamy oil at 20 MPa was 2.93 times larger than that at 8.65 MPa. The diffusion coefficient of the natural gas in dead oil was 3.02 and 4.02 times than that of the natural gas in saturated oil and foamy oil when the pressure was 20 MPa. However, the gas content of foamy oil was 16.9 times higher than that of dead oil when the dissolution time and pressure were 20 MPa and 35.22 h, respectively.

草27特-超稠油油藏开发现状及配套工艺应用分析

乐安油田草27区块是特-超稠油油藏,由于特-超稠油油藏原油粘度很高,故采取多种配套工艺注采,包括完井防砂工艺和井筒降粘举升工艺,大大的提高生产了效率。文章针对草27区块配套工艺的应用情况,结合实际对各个工艺效果进行分析,配套工艺的使用大大的提高了草27区块产能水平。

First Evidence of Fungal Strains Isolated and Identified from Naphtha Storage Tanks and Transporting Pipelines in Venezuelan Oil Facilities

Biocorrosion, as well as the biodeterioration of crude oil and its derivatives, is one of the major environmental, operational and economic problems in the Venezuelan oil industry. Fungal contaminants are able to produce large quantities of biomass and synthesize peroxides and organic acids, causing severe damage on metal surfaces and promoting the contamination and biodeterioration of fuels. No evidences regarding fungal strains have been reported to be associated to petroleum naphtha, widely used as a diluent of extra heavy crude oil (EHCO) in the exploitation processes of the Orinoco Oil Belt, the biggest proven reserve of EHCO worldwide. The aims of this paper were to isolate and identify fungal strains from the naphtha storage tank and the naphtha distribution network from an oil field operator in Venezuela. The results showed the isolation of four different fungal strains. The molecular identification by 28S rRNA sequencing and phylogenetic tree analysis allowed us to identify the presence of: 1) a new uncultured Ascomycota fungus species BM-103, with high identity to novel hyphomycetes Noosia banksiae and Sporidesmium tengii, in the naphtha storage tank;2) two yeasts, Rhodotorula mucilaginosa BM-104 (Phylum Basidiomycota) and Wickerhamia sp. BM-105 (Phylum Ascomycota), in a highly damaged naphtha pipeline branch and;3) Cladosporium cladosporioides BM-102 (Phylum Ascomycota) in a cluster oil well. DNA fingerprinting analysis using ERIC-PCR primers pairs also allowed us to detect the presence of R. mucilaginosa BM-104 right in the access of the studied naphtha system. Interestingly, R. mucilaginosa and C. cladosporioides were previously reported as predominant fungal contaminants of diesel and jet fuel and of kerosene and fuel storage systems, respectively. This paper represents the first evidence of fungal strains isolated and identified from the naphtha systems in the Venezuelan oil industry. The results obtained are discussed.

新型环乙烷降黏剂与特超稠油混合体系流动性能评价实验

特超稠油黏度超过100000 mPa·s,流动性差、开采难度大、热采能耗高,降黏剂辅助是特超稠油开采技术重要改进方向。本文针对研发的新型环乙烷降黏剂,采用新疆春风油田特超稠油油藏作为研究样本,通过室内评价实验研究了温度、降黏剂浓度、降黏剂体积含量对特超稠油降黏效果的影响规律。研究发现特超稠油黏度随温度增加呈指数式降低,随降黏剂浓度和含量增加呈乘幂式降低,对降黏效果影响敏感性降黏剂含量>降黏剂浓度>温度;同时,对比发现10%浓度、10%体积含量的降黏剂对特超稠油降黏效果相当于提高地层温度40℃时的降黏效果,并在此基础上明确了该新型降黏剂使用参数界限。该研究对于提高特超稠油油藏采收率和降耗增效具有指导借鉴价值。

适用于特稠油的耐高温高盐纳米二氧化硅降黏驱油剂

乳化降黏是稠油提高采收率的关键技术之一。普通降黏剂无法同时满足特稠油热采时的高温与高矿化度要求,导致降黏剂失活、降黏效果差、采收率低。以纳米硅溶胶、两亲型分散剂、修饰剂硅烷偶联剂、增效剂两亲型表面活性剂等为原料,制得纳米降黏驱油剂,表征了驱油剂的微观结构,评价了驱油剂对特稠油的降黏效果、耐温耐盐性能、吸附性能和驱油效果。结果表明,驱油剂配方组成为:50%SiO_(2)+40%分散剂+4.2%表面修饰剂+5.8%增效剂。驱油剂粒径约50 nm,粒径分布均匀,分散性良好。1%驱油剂未老化前,对特稠油的降黏率达84.99%,在矿化度为15 g/L、350℃下老化2 h后的降黏率为83.62%,降黏性能保持率为98.39%。驱油剂可使砂岩表面由疏水性转变为亲水性。在50℃、液固比为10∶1、平衡吸附时间为15 h的条件下,驱油剂在油砂表面的静态吸附量为1.377 mg/g砂;1%驱油剂在填砂管的动态吸附量为0.745 mg/g砂,在油藏中的吸附损失较低,符合化学驱对表面活性剂的吸附损失要求。在一维驱替实验中,驱油剂的驱油效率比普通蒸汽驱提高了26.7百分点,在350℃、老化2 h后的驱油性能保持率为97.0%。纳米降黏驱油剂具有良好的降黏效果、耐温耐盐性能、吸附性能和驱油效果,可降低驱油成本,有效提高特稠油的热采开发效果。

浅薄层特稠油油藏大井距蒸汽吞吐转蒸汽驱先导试验

针对春风油田浅薄层特稠油油藏高轮次吞吐阶段后单井产能低,产量递减大,油汽比低,动用不均衡等问题,对排612块试验区开展蒸汽驱先导试验,运用数值模拟和油藏工程方法,对蒸汽吞吐后转蒸汽驱合理井网井距、转驱时机及注采参数等指标进行优化。研究结果表明,浅薄层特稠油油藏大井距蒸汽吞吐转蒸汽驱是可行性的,开展蒸汽驱8个月,阶段产油0.68×10^(4)t,油气比0.07,试验取得一定的效果,为同类型油藏开展蒸汽驱提供一定的借鉴意义。

特超稠油油藏热化学协同作用研究

渤海D油田属于典型的特稠油油藏,此类稠油在地层条件下流动性差,常规蒸汽吞吐开发效果较差,需要辅助化学增效来改善开发效果。通过一维高温驱替实验装置和高温高压微观驱替物理模拟实验装置,利用室内物模实验研究了蒸汽复合化学增效过程及热复合化学驱增效机理。研究发现:蒸汽复合化学驱能明显提高特稠油采收率,其增产机理体现在利用蒸汽热降黏,化学药剂辅助降低黏度,并通过调堵提高蒸汽利用率,蒸汽复合化学驱较单一蒸汽驱驱油效率提高幅度达到16%,蒸汽复合化学体系中降黏剂能溶解稠油中的胶质、沥青质,降黏率达70%,并大幅度降低屈服值改变稠油流变性,降低启动压力,利于特稠油在储层渗流;120℃条件下,蒸汽复合化学增效能将油水界面张力降低至10^(-5)mN/m水平,提高驱油效率;此外,泡沫还能对高渗层进行封堵,提高低渗层驱油效率15%。研究成果为海上特稠油的高效开发提供了理论指导。

特(超)稠油流变特性试验研究及应用

针对辽河油田的特、超稠油独特的流动特征 ,用旋转法测定原油的流变性 ,研究其流变特性及其粘度影响因素 ,为开发此类油藏提供依据。研究结果认为 :当高于原油的拐点温度 ( 5 5～ 6 5℃ )时 ,原油流动性明显变好 ;特 (超 )稠油具有较大的屈服值 ,流动性差 ,因此应尽可能连续开井生产 ,以避免因停产而造成较大的启动压力 ;对于高粘度原油 ,剪切速率影响其粘度 ,开采时保持适当的采油速度 ,可以提高产量。

超稠油油藏蒸汽与非凝析气驱油数字化实验

在蒸汽辅助重力驱油(SAGD)工艺物理模拟相似准则的基础上,以辽河油田某区块地质特征为原型建立比例物理模型,进行了蒸汽辅助重力驱油(SAED)与蒸汽与非凝析气驱油(SAGP)物理模拟数字实验。得到了两种工艺开采过程的温度场和生产指标结果,对比分析了其开发效果的优劣,并对SAGP过程注非凝析气的种类进行了优化。研究表明:SAGP过程添加非凝析气后,使得蒸汽腔的横向扩展加快,垂向扩展减缓;SAGP过程能减少蒸汽注入量和热损失,增大热效率,提高油汽比,改善蒸汽辅助重力泄油的开发效果;SAGP过程注二氧化碳的开发效果优于注烟道气,注烟道气优于注氮气;SAGP技术可在提高采收率的同时减少开采过程能量消耗,并有效利用温室气体。

超稠油油藏直井与水平井组合SAGD技术研究

辽河油田曙一区杜84块兴隆台油层兴Ⅵ组为厚层块状超稠油油藏,50℃下脱气原油黏度大于100Pa.s。针对该油藏的地质特征、原油性质与开发现状,分析了直井与水平井组合蒸汽辅助重力泄油(SAGD)技术的适应性,在现有直井已吞吐多个周期、地层压力已大幅下降的情况下,应用数值模拟技术研究了直井与水平井组合SAGD技术的水平井部署方式并对SAGD注采参数进行了优化。研究结果表明,直井与水平井组合SAGD技术是杜84块兴Ⅵ油层组超稠油油藏蒸汽吞吐后的有效接替技术,可提高原油采收率30%,累计油汽比可达到0.296。最佳的布井方式为水平生产井在两排垂直井中间,且位于侧下方,垂向距离为20m,水平井段长度为280m;井底注汽干度必须大于70%,且生产井排液速度必须与注汽井注汽速度相匹配。

辽河超稠油电化学脱水实验研究

针对目前国内超稠油预处理脱水主要采用的热化学沉降脱水或掺稀释剂脱水工艺的不足和局限,根据辽河超稠油的含水量及原油性质,对超稠油电化学脱水技术进行了开发研究。考察了温度、破乳剂、强弱电场等操作条件对辽河超稠油脱水效果的影响;在外加电场中,利用开发的快速脱水剂与破乳剂协同作用,实现了超稠油的深度脱水。在优化的电化学脱水工艺条件下,当破乳剂用量为140μg/g,脱水剂用量为80μg/g时即可使脱水后原油的含水率达到1.8%,而且经脱水处理后油品的密度有所降低,在50℃时粘度降低幅度达到60%,显著改善了油品的储运性能,有利于超稠油的后续加工利用,同时为辽河超稠油预处理脱水工艺的升级换代提供了一项新技术。