Nucleation of methane hydrate and ice in the emulsions of water in five kinds of crude oils

In this work the model which allowes to receive information about characteristics (number, content and relative activity) of heterogeneous nucleation centers in dispersed systems with metastable dispersed phase was used to treat the experimental results on the nucleation of methane hydrate and ice in the water-in-crude oil emulsions. More than ten types of nucleation centers differing from each other in activity was detected in the experiments. Hydrate and ice nucleation occured in the temperature intervals 264–269?K and 261–265?K, respectively.     

Synergistic effect of demulsifiers with different structures for crude oil emulsions

In practice, synergetic effect of the interaction between different demulsifiers is often sought for dewatering the water in oil emulsion of crude oil. Surface tension, interfacial tension, interfacial shear rheology and demulsification test was employed to study the synergistic effect of demulsifiers with different molecular structures, one is the strait-chain demulsifier SP31 and the other branch-chain demulsifier AE31. The strait-chain demulsifier SP31 has a lower IFT but a longer balance time compared with the branch-chain demulsifier AE31. The dewatering rate of AE31 is faster than that of SP31 but the separated water after demulsification for 1 h by SP31 is clearer. It is mainly because the branch-chain demulsifier has stronger penetrability at oil/water interface. When the percentage of SP31 is 40～60%, the complex demulsifier of SP31 and AE31 exhibits the synergistic effect of demulsification performance due to the instantaneous relatively low interfacial tension and the strongest capacity to decrease the strength of the oil-water interfacial film.     

高含水原油旋流预脱水及污水除油试验与研究

为处理含水率≥ 90 %的高含水原油 ,将两级液 液旋流器串接 ,在东辛采油厂辛二接转站进行了旋流预脱水和污水除油一体化现场试验。通过改进旋流器结构和优化试验参数 ,在处理量为 4～ 6m3/h的小型改进装置上初步达到了预期目标。随后开展了一体化工艺的工程应用及配套研究 ,通过在辛二接转站一期和二期示范工程的实施 ,最终实现了中石油集团公司提出的技术攻关目标 :两级旋流器处理后的原油含水率≤ 30 % ;污水含油≤ 30mg/L     

射线型原油含气、含水率自动监测仪原理及应用

射线型原油含气、含水率自动计量系统是基于油、气、水三种不同介质对一定能量的γ射线的吸收不同，通过检测γ射线穿过油、气、水的混合物后的透射计数，理论计算，实现对原油含气、含水率的在线分析。工作方式为全自动在线连续测量，该计量监测系统设计新颖、测量准确、安全可靠、运行稳定、使用寿命长、便于操作，特别是修正了由于原油中含气对含水率测量的影响，使该仪表在安塞油田的原油计量中发挥了明显的优势。     

Comparative studies of the rheological behavior and microstructural properties of emulsions (oil/distilled water phase) and (oil/Lias water phase)

Abstract

The rheological behavior of crude oil and their emulsions were investigated as a function of two water types (distilled water and the LIAS water). The focus of this work is to obtain more knowledge about the effect of LIAS water concentration, which used to maintain pressure and produced from production of crude oil in the oil fields Tin Fouye Tabankort-south Algeria, on the rheological properties of crude oil. The rheological parameters were measured by using AR-2000 rheometer at 15?°C under dynamic and shear testing conditions. The measured data were first classified into two groups for Newtonian and non-Newtonian fluids. Depends on the type and concentration of water, the non-Newtonian behavior was described in better way by the Casson, Power law and the Herschel–Bulkley models. The results indicated that the viscosity, the yield stress, the elastic modulus, (G′), the loss modulus, (G″), and the microstructure of the prepared emulsions not only varied with water concentration but also by water types.     

低剂量天然气水合物抑制剂对渤海M油气田原油破乳脱水的影响

通过室内实验研究了包括3种动力学抑制剂与3种阻聚剂在内的6种低剂量天然气水合物抑制剂对渤海M油气田原油破乳脱水的影响,结果表明:当加注质量浓度为10～50 g/L时,3种动力学抑制剂ISP501、HY-2和HY-3对该油气田原油破乳脱水基本没有影响,仅使油水界面变差,但同时使用破乳剂AP-10能明显改善油水界面;3种阻聚剂HY-4、HY-5和HY-6对该油气田原油破乳脱水的影响程度与阻聚剂的分子结构类型有关,HY-4没有影响,HY-6有加重油水乳化的趋势,HY-5在水相产生大量絮状物,同时使用破乳剂AP-10作用也不大。动力学抑制剂ISP501和HY-3在渤海M油气田现场试验取得了较好的效果,原油处理合格,外排污水达标。     

Prediction of transient pressure change during natural gas hydrate formation

Abstract

The increasing demand for fossil fuels and diminishing natural energy reserves have necessitated the exploration of gas hydrates. Gas hydrates find importance in oil and gas industries where the formation and dissociation of gas hydrate become important. Thus, the proper understanding of formation, decomposition and properties of gas hydrates is a required. In this work, a macroscopic kinetic model is analyzed and modified to predict the pressure change with time during the hydrate formation based on the chemical affinity of compounds. With the help of experimental data, the degree of parity of the modified and unmodified models are explained. The dependency of the chemical affinity of the gas hydrate reformers is explained based on the kinetic model validation with the experimental results. The modified model predict the transient pressure during gas hydrate formation with an average absolute error of 3.6%.     

Natural gas hydrate formation dynamics in a diesel water-in-oil emulsion system

Abstract

Although gas hydrate is an excellent clean fuel and energy storage form, its natural generation rate is very slow. The key to accelerate the industrialization is to find an appropriate promotion method. In this paper, Span80 and Tween80 were used to study the rapid formation technology of hydrate in diesel water-in-oil emulsion at 275.15 K and 7?MPa. Firstly, hydrate formation in different water cut systems was studied. Results show that hydrate with higher water cut has a faster formation rate and a higher gas storage density, and the system has the shortest induction time with a 40% water cut. The addition of PEG400 and SDS to the original emulsion system resulted in higher gas densities and denser hydrates. Moreover, the addition of emulsifier can reduce the interfacial energy and form a stable interface membrane. Gas storage density also reflects the same phenomenon. Finally, the double electron layer structure formed by different charged ions can also make the emulsion system more stable and promote hydrate formation. Hydrate can be rapidly formed in the diesel water-in-oil emulsion system, which has a great reference value for the future hydrate storage and transportation.     

Determination of water content in crude oil emulsion by LF-NMR CPMG sequence

Transverse relaxation times (T2) and T2 spectrum for crude oil emulsions with different water content are obtained by low field nuclear magnetic resonance Carr-Purcell-Meiboom-Gill sequence and various methods to determine the water content are investigated. The results show that there are three methods to accurately determine the water content. When water content is greater than 20.0wt%, determination through T2 value of emulsions is fastest with the relative error below 2.5%. T2 spectrum show the characteristics of multiple peaks, and T2 value of the peaks originated from water are suitable for determination of water content for O/W emulsions. A method is developed and optimized to determine the water content by using the peak-area ratio in T2 spectrum, which is not limited by the water content and the form of emulsion.     

利用地层产水率参数判断稠油等级

方法 利用产水率与含水饱和度组合参数，对稠油储层进行研究。目的 划分稠油等级，优选开采方案。结果 地层产水，产油率与含水，含油饱和度组合参数（ｆ０ｓ０和ｆｗＳｗ）其比值（ＦＳＫ）大于１，稠油等级高，热采效果好，产量高，等于１，稠油等级低，热采效果差，产量低；小于１，热采无效果，无论 用该方法确定的稠油等级较目前采用的其它方法效果好，简便易行且应用范围较广 。     

A study of hydrate plug formation in a subsea natural gas pipeline using a novel highpressure flow loop

The natural gas pipeline from Platform QK18-1 in the southwest of Bohai Bay to the onshore processing facility is a subsea wet gas pipeline exposed to high pressure and low temperature for a long distance. Blockages in the pipeline occur occasionally. To maintain the natural gas flow in the pipeline, we proposed a method for analyzing blockages and ascribed them to the hydrate formation and agglomeration. A new high-pressure flow loop was developed to investigate hydrate plug formation and hydrate particle size, using a mixture of diesel oil, water, and natural gas as experimental fluids. The influences of pressure and initial flow rate were also studied. Experimental results indicated that when the flow rate was below 850 kg/h, gas hydrates would form and then plug the pipeline, even at a low water content (10%) of a water/oil emulsion. Furthermore, some practical suggestions were made for daily management of the subsea pipeline.     

油气混输管道中天然气水合物的形成和堵塞过程研究

为研究油气混输管道中天然气水合物的形成和堵塞过程,采用自行设计的高压环道装置,以去离子水、柴油、天然气为管输介质,在含水率70%、液相初始流量2 000kg/h等条件下进行水合物堵塞实验。研究结果表明:实验时水合物在管道中各处同时生成,但初始生成量并不相同;在实验含水率70%的条件下,水合物主要在管道气相空间壁面和液相主体中生成;水合物的生成会导致管内流量降低,在未添加乳化剂的情况下,油水混合液会因流量的降低而产生分层,此时水合物颗粒集中分布在混合液下层,造成流体黏度和管段压降的急剧升高,进而引发管道堵塞。     

不同类型体系下复合型添加剂对水合物生成的影响

通过实验研究了纯水和盐类体系下复合型添加剂对水合物生成的影响,选用甲基环己烷(MCH)与NaCl分别和阴离子表面活性剂十二烷基苯磺酸钠(SDBS)混合溶液作为实验溶液。研究发现,两种类型体系相比较,NaCl+SDBS混合溶液在SDBS浓度为255mg/kg时诱导时间最短,为复合型添加剂的最佳反应浓度,此时的溶液体系能很好地优化水合物形成过程,且比单一的NaCl溶液、MCH溶液或SDBS溶液的诱导时间都有明显缩短,此时的氯化钠溶液浓度为海水浓度。此数据对今后储存运输水合物有着重要的指导意义。     

Influence of polymers on the stability of Gudao crude oil emulsions

The influence of different types and concentrations of polymers on the stability of Gudao crude oil emulsion was investigated by measuring the volume of water separated from the emulsions and the interfacial shear viscosity of the oil/water interfacial film. Experimental results indicate that the simulated water-in-oil emulsion with 40 mg/L of partially hydrolyzed polyacrylamide （HPAM） 3530S could be easily broken by adding demulsifier C and was readily separated into two layers. However, HPAM AX-74H and hydrophobically associating water-soluble polymer （HAP） could stabilize the crude oil emulsion. With increasing concentration of AX-74H and HAP, crude oil emulsions became more stable. Water droplets were loosely packed in the water-in model oil emulsion containing HPAM 3530S, but water droplets were smaller and more closely packed in the emulsion containing AX-74H or HAP. The polymers could be adsorbed on the oil/water interface, thereby increasing the strength of the interracial film and enhancing the emulsion stability.     

Effect of a nonionic surfactant on the formation of natural gas hydrate in a diesel emulsion system

Abstract

In order to investigate the effect of different nonionic surfactants on hydrate formation in oil-water emulsion systems, the hydrate formation experiments were carried out in a diesel water-in-oil emulsion system with a water cut of 40% using nonionic surfactants such as Span80, Tween80, Span20 and Tween20, respectively. The results show that under the experimental conditions of 275?K and 7?MPa, a certain concentration of nonionic surfactant can promote the growth of hydrates in diesel emulsion systems, shorten the hydration reaction time, and have a significant effect on the improvement of gas storage density. The combination of Span80 and Tween80 in a mass ratio of 1:1 was the most effective in promoting the formation of hydrate in the emulsion system. When the mass fraction was 0.5%, the hydration reaction time was the shortest and the hydrate gas storage density was the highest. Due to the addition of the nonionic surfactant, a stable interfacial film and interfacial charge are formed around the water droplets of the emulsion system, making it difficult for the droplets to approach and polymerize, which maintains the stability of the water-in-oil emulsion system and has great reference value for the study of hydrate storage and transportation.     

ASP驱油体系各组分对原油乳状液稳定性的影响

研究ASP驱油体系各组分对原油乳状液的影响,有助于改善ASP驱油体系,进一步提高驱油效率。以NaOH为碱组奇,聚乙二．醇辛基苯基醚、石油磺酸盐为表面活性剂组分,部分水解聚丙烯酰胺为聚合物组分,考察了ASP驱油体系中的碱、表面活性剂和聚合物以及无机盐等对原油乳状液稳定性的影响。实验结果表明：对于实验原油,NaOH的质量分数为0.40％,石油磺酸盐的质量分数为0．02％,部分水解聚丙烯酰胺的质量分数为0．03％时,原油乳状液的稳定性较好。针对不同特性的原油,可按照ASP驱油体系各组分对原油乳状液稳定性的影响规律来调整各组分的比例,从而达到最佳的驱油效果。     

Experimental study and modeling of the kinetics of gas hydrate formation for acetylene,ethylene, propane and propylene in the presence and absence of SDS

The kinetics of hydrate formation of the hydrocarbons acetylene, ethylene, propane, and propylene were investigated using a fully stirred batch reactor. In relation to hydrate formation, a kinetic model was used to determine the induction time, the rate of hydrate formation, the apparent hydration rate constant, water-to-hydrate conversion associated with hydrate growth as well the storage capacity. This was done for all gases investigated in this study. Experiments were performed in the temperature and pressure ranges of (273.7–280.0) K and (0.5–4.12) MPa, respectively. Furthermore, the effect of sodium dodecyl sulfate (SDS) on the gas hydrate formation rate was examined. A substantial growth in the hydrate nucleation rate was observed in the presence of SDS.     

强边水普通稠油断块油藏挖潜研究

针对Z43断块普通稠油强边水油藏目前开发中存在的问题,开展了剩余油挖潜技术研究。在控油断层、微构造、隔夹层等地质精细研究的基础上,建立了三维地质模型。开展普通稠油油藏高含水期剩余油分布研究,制定了挖潜方案,提出了常规井、侧钻井继续落实控油断层,短井段水平井挖潜剩余油的思路,现场实施取得了较好的效果。该断块类型油藏的成功挖潜对类似油藏后期开发具有一定的指导意义。     

高含水原油对水力旋流器预分离性能的影响

简述了高含水原油经水力旋流器分离时出现乳化的原因, 讨论了影响水力旋流器高含水原油预分离性能指标, 并对影响高含水原油预分离性能的重要参数———旋流器入口流量、分流比、压降和溢流口直径等分别进行了试验。试验结果表明, 当水力旋流器的流量、分流比和压降比控制在一定范围内时, 选择适当溢流口直径才能同时提高分离效率和脱水效率, 使高含水原油预分离后溢流的含油浓度满足生产要求, 底流口污水的含油浓度也满足后续除油工艺要求。     

Optimization of chemical demulsifications of water in crude oil emulsions

The instability of the water in crude oil emulsion and separation of the dispersed water as free water are influenced by the emulsion properties and the operating parameters during the demulsification process. This study aims to relate these properties/operating parameters to the amount of separated water. Steps were taken to determine and validate the optimal separations that can be achieved. Six operating parameters were identified through sensitivity analyses to have an energetic effect on percentage water separation. The bottle test method was used on two different samples of water in oil synthetic emulsions (sample A and B from different Nigerian oil fields). Response surface methodology central composite design (RSMCCD) was used to design the experiment, and generate the desired regression equations/models. Results show that optimum percentage water separations of 93 and 95% (V/V) were achieved with the emulsions A and B respectively using the combination of the optimal variables derived from the model equations. These were improvements from percentage water separations of 80 and 83% (V/V) achieved using the two crude oil samples in their naturally occurring state when the properties of the emulsions were not enhanced to their determined optimal operating conditions.