Characterization of ternary compound viscosity reducer system on viscosity of viscous crude oil

Based on the theory that viscous crude oil can form stable two-phase oil-water interfacial molecular membrane with surfactant, the oil-water interfacial activity and viscosity reduction of oil-water interface of viscous crude oil were studied for the ternary compound system, including anionic surfactant alpha olefin sulfonate (AOS), weak alkali Na₂CO₃ and four different kinds of nonionic surfactant emulsifying silicon oil (LKR-1023), lauryl diethanolamide (LDEA), isomeric alcohol ethoxylates (E-1306), and polyoxyethylene sorbitan monooleate (T-80). Results showed when lipophilic or hydrophilic nonionic surfactants were used separately in the same compound system. The viscosity of viscous crude oil could be reduced, but the viscosity reduction efficacy was not desirable. However, using LKR-1023, E-1306, and T-80 as nonionic surfactant with mass fraction 1.0%, the viscosity reduction rate of viscous crude oil reaches 98.92%, 98.29%, and 96.87%, respectively. With 1.4% of LDEA, the viscosity reduction rate of viscous crude oil can reach 98.89%. Through all different kinds of the nonionic surfactant tested, oil-in-water (O/W) emulsion under LDEA ternary compound system has been proved to be the most stable with no phase inversion. Therefore, it is promising to improve the viscosity reduction of the super viscous crude oil by selecting the proper surfactant and dosage.     

Mechanism of viscosity reduction in viscous crude oil with polyoxyethylene surfactant compound system

Surfactant can be used to form stable oil-in-water emulsion and reduce the viscosity of viscous crude oil. The mechanism of viscosity reduction was studied for nonionic surfactant alkylphenol polyoxyethylene (9) ether (APE-9) compound systems. The results showed that the viscosity reduction of viscous crude oil by water-insoluble alkylphenol polyoxyethylene (4) ether (APE-4) was higher than sodium dodecyl sulfate (SDS, anionic surfactant) and dodecyl dimethyl betaine (BS-12, amphoteric surfactant) in the binary compound system. The viscosity further decreased by ethanolamine. The interfacial tension (IFT) study showed that when the reduction in IFT was the highest, the viscosity reduction was the highest.     

Mechanism of the viscosity reduction with ternary compound in the sulfonate-straight chain alcohol-alkaline compound system

Research shows that the viscosity greatly reduction of viscous crude oil can improve the exploitation and promote the fluidity. We studied the effects and the mechanism of viscosity reduction of viscous crude oil emulsion after introducing the ternary compound of sulfonate-straight chain alcohol-alkaline as the viscosity reducer. Results showed that the best emulsifying performance can be achieved using 5% 1-pentanol. 0.2% of Na₂CO₃ and DEA shows the strongest emulsification ability of the O/W emulsion. The use of AOS, straight chain alcohol and petroleum carboxylate resolves diffusion on the oil-water interface, which can form a dense surfactant of single molecular layer to reduce the interfacial tension and prevent the phase change of the emulsification. When the mass fraction of AOS, Na₂CO₃, DEA and 1-pentanol were 0.2%, 0.25%, 0.2% and 5% respectively, the viscous crude oil would achieve the best effect of viscosity reduction.     

RHEOLOGY, PARTICLE SIZE DISTRIBUTION, AND ASPHALTENE DEPOSITION OF VISCOUS ASPHALTIC CRUDE OIL-IN-WATER EMULSIONS FOR PIPELINE TRANSPORTATION

The rheology of an asphaltic heavy crude oil-in-water emulsions stabilized by an anionic (RN) and a nonionic (TEP) surfactants individually or in a mixture has been studied. The investigated crude oil has a non-Newtonian, time dependent, shear thickening, rheopectic behavior with a relatively high yield stress. The relatively high yield stress of this crude oil is attributed to the presence of a relatively high asphaltene and resins content. The viscosity ofhe crude oil decreases when it is emulsified with synthetic formation water in the form of an oil-in-water type of emulsion using a nonionic or an anionic surfactant. It has been found that, the maximum oil content required for forming an oil-in-water emulsion of acceptable viscosity is the 60% oil-containing emulsion. However, the 70% oil-containing emulsion is not an oil-in-water type of emulsion but it is rather a complicated mixture of oil-in-water-in-oil type of emulsion. The presence of the anionic and the nonionic surfactants together has a synergistic effect in decreasing the total surfactant concentration required to stabilize the emulsion and to form low viscosity emulsion. It has been emphasized that the nonionic surfactant has a positive contribution in forming emulsions with low viscosity. Meanwhile, the anionic surfactant contributes in stabilizing the emulsion at lower concentrations. Flocculation point measurements showed that the added surfactants caused no sign of asphaltene deposition. This implies that it is safe to use the investigated surfactants in forming oil-in-water emulsion for viscous asphaltic crude oils without any fear of asphaltene deposition.     

RHEOLOGY,PARTICLE SIZE DISTRIBUTION,AND ASPHALTENE DEPOSITION OF VISCOUS ASPHALTIC CRUDE OIL-IN-WATER EMULSIONS FOR PIPELINE TRANSPORTATION

The rheology of an asphaltic heavy crude oil-in-water emulsions stabilized by an anionic (RN) and a nonionic (TEP) surfactants individually or in a mixture has been studied. The investigated crude oil has a non-Newtonian, time dependent, shear thickening, rheopectic behavior with a relatively high yield stress. The relatively high yield stress of this crude oil is attributed to the presence of a relatively high asphaltene and resins content. The viscosity ofhe crude oil decreases when it is emulsified with synthetic formation water in the form of an oil-in-water type of emulsion using a nonionic or an anionic surfactant. It has been found that, the maximum oil content required for forming an oil-in-water emulsion of acceptable viscosity is the 60% oil-containing emulsion. However, the 70% oil-containing emulsion is not an oil-in-water type of emulsion but it is rather a complicated mixture of oil-in-water-in-oil type of emulsion. The presence of the anionic and the nonionic surfactants together has a synergistic effect in decreasing the total surfactant concentration required to stabilize the emulsion and to form low viscosity emulsion. It has been emphasized that the nonionic surfactant has a positive contribution in forming emulsions with low viscosity. Meanwhile, the anionic surfactant contributes in stabilizing the emulsion at lower concentrations. Flocculation point measurements showed that the added surfactants caused no sign of asphaltene deposition. This implies that it is safe to use the investigated surfactants in forming oil-in-water emulsion for viscous asphaltic crude oils without any fear of asphaltene deposition.     

稠油降粘剂DJH-1

稠油降粘剂ＤＪＨ－１是由表面活性剂和助剂组成的复合体系,它对胜利油田东辛断块,草桥的稠油有较好的降粘作用,本文介绍了ＤＪＨ－１的降粘性能和典型应用实例。     

稠油地下催化降粘效果影响因素室内实验研究

在模拟油藏条件和不改变目前蒸汽吞吐工艺的条件下,利用胜利油区单家寺油田单六区东块稠油,选择硫酸镍、硫酸钴、硫酸亚铁、硫酸铁、三氯化铁、氯化亚铁和磷钼酸铵等7种可溶性盐作为催化剂配方成分,进行了复配体系筛选,并利用优选出的催化剂体系,研究在地层中对稠油进行催化改性降粘的可行性及催化降粘效果的影响因素.结果表明:特稠油或超稠油体系在蒸汽开采中具有被催化降粘的可能性,不同催化剂体系的催化效果差别很大;催化剂质量分数、催化反应温度和时间共同影响催化剂体系的降粘效果;pH值小于4和含水率为15％～50％的油藏催化降粘效果较好.因此,针对不同原油和开采状况需要选择不同的催化剂体系.     

Comparative Studies on Synthetic and Naturally Extracted Surfactant for Improving Rheology of Heavy Crude Oil

Effect of surfactants on rheological properties of heavy crude oil obtained from Mehsana Asset, Gujarat, India, were studied. Studies on effectiveness towards flow behavior were made using a surfactant extracted from a tropical Indian plant Madhuca longifolia (Mahua) and nonionic surfactant Brij-30 considering various contributing parameters such as temperature, concentration, and shear rate. Tests were performed at controlled shear rate. At 25°C, 2000 ppm Mahua and Brij-30 addition reduced viscosity of crude oil by 48% and 52%, respectively. Complex and viscous modulus of crude oil decreased significantly due to addition of both the surfactants. FTIR studies of crude-surfactant mixture showed remarkable decrease in concentration of viscosity enhancing groups such as alkanes, alcoholic, and acidic groups indicating the effectiveness of both the surfactants. Naturally extracted surfactant may be used as flow improver for transporting heavy crude oil.     

Investigation of factors affecting on viscosity reduction of sludge from Iranian crude oil storage tanks

Crude oil is a kind of water/oil emulsion, which the oil phase consists of organic molecules with different molecular weights such as alkanes, paraffin, asphaltene, and resins. Due to the change in physicochemical conditions during the production, transportation, storage, and refining, heavier molecules can precipitate from crude oil. Thus, viscous sludge formed at the bottom of storage tanks can cause many problems including reduction of storage capacity of tank, oil contamination, corrosion, repair costs, environmental pollution, etc. The reduction of sludge viscosity can be achieved by reduction of its interfacial tension. In this study, different chemical and physical factors, influencing prepared emulsions (made of sludge, water and surfactant), such as surfactants, solvents, temperature, pressure, and mixing conditions were investigated. Results showed that non-ionic surfactants (like bitumen emulsifier), and solvents (such as mixed xylene, AW-400, and AW-402), injection of additives, applying pressure, and mixing operations had a positive effect on reduction of emulsion viscosity. All experiments were carried out with sludge obtained from crude oil storage tanks at Kharg Island, Iran.     

三元复合驱采出污水油水分离影响因素分析

三元复合驱采出污水中含有聚合物、表面活性剂和碱等驱油剂组分,使得水质变得极为复杂,油水稳定性明显增加,处理难度加大。探讨了聚合物、表面活性剂、碱等驱油剂组分对采出污水油水稳定性的影响,对驱油剂组分增强采出污水稳定性的作用机理进行了分析。结果表明:聚合物浓度增加,使得油珠Zeta电负性增加,采出污水黏度增加,油水分离的速度变缓,沉降时间增加;表面活性剂在低浓度时能降低表面张力,其与聚合物的协同作用能大幅度提高污水含油量;碱与原油中的石油酸反应能生成表面活性物质,使得油水界面张力降低,污水稳定性增加,污水中含油量增加。     

The Effect of Alkali and Surfactant on Polymer Molecular Structure

Abstract

With the technical development of enhanced oil recovery (EOR), the alkali/surfactant/polymer (ASP) compound flooding technique has been the necessary choice in Daqing oilfield. Compared to average polymer flooding, ASP compound solution decreases the interfacial tension (IFT) between water and crude oil; however, the viscosity and viscoelasticity of ASP solution were performed by surfactant and alkali, both of which could affect the polymer moleculal structure and the oil recovery of ASP flooding. Considering practical requirements in oilfield development, much effort has been focused on the effect of alkali and surfactants on polymer solution by laboratory experiment and theoretical analysis. The results indicate that alkali and surfactants cause the interfacial tension decrease; at the same time, the molecular structure of the polymer is changed and the viscosity and viscoelasticity of polymer solutions are decreased. In addition, alkali neutralizes with negative ion on polymer molecular and causes the polymer molecular chains to curl up, forming a “band” molecular structure. Those actions could make viscoelastic behavior and rheological property of ASP solution weak.     

应用降粘剂提高大港稠油油藏水驱采收率

在对大港官109-1断块稠油组成及结构进行分析的基础上,针对油藏高温、高矿化度及水驱采出程度低的特点,研制出一种降粘剂。在含水量大于30%及降粘剂加入量大于1 000 mg/L（占油水总质量）的条件下,能使油水体系形成稳定的O/W乳液,降粘率大于97%,且降粘剂的存在对采出液的破乳脱水没有负面影响。岩心驱油实验结果表明,降粘剂驱油体系比水驱体系稠油采收率提高22%以上,说明使用降粘剂可降低油藏稠油粘度,改善水/油流度比,提高波及系数,明显改善水驱效果。     

塔河油田油溶性降黏剂的制备

以丙烯酸高碳醇酯苯乙烯共聚物、丙酮、无规聚醚、乙二醇、有机溶剂为原料,制备了适用于塔河油田的降黏剂,确定了降黏剂最佳配方:m(丙烯酸高碳醇酯苯乙烯共聚物)∶m(丙酮)∶m(无规聚醚)∶m(乙二醇)∶m(有机溶剂)=17∶7∶15∶8∶53,并评价了其降黏效果。现场应用结果表明,塔河油田使用降黏剂开采稠油,平均产油量35.1 t/d,平均节约稀油量21.5 t/d。     

Double alkyl chain copolymers as flow improvers for heavy oil

As flow improvers for heavy crude oil, two oil-soluble copolymers (DM-S-VA, DA-S-VA) were successfully synthesized and characterized by ¹H NMR and GPC. A rich alkyl chain and appropriate molecular weight of copolymer play fundamental role in viscosity reduction of heavy oil. Furthermore, synergistic effect of surfactants on polymers can promote the viscosity reduction, and the best formulation can increase the viscosity reduction rate to 78% to oil A. Comparing with the apparent viscosity of the different heavy oil mixing system in a wide shear rate range (0.1–200 s^?1), the results show good stability and viscosity reducing effect.     

稠油降粘剂复配及降粘效果研究

研究了温度、单一降粘剂和复配降粘剂体系对河南某油田稠油的降粘效果,结果表明,稠油粘度随着温度上升而下降,当温度高于60℃时,粘度随温度升高下降缓慢并逐渐趋于稳定。等量等温试验条件下选取的5种降粘剂中AES的降粘效果最好,确定的降粘剂复配体系最佳复配条件为：AES用量0．2％,温度80℃,OP-10用量0．2％,十二烷基磺酸钠用量0．4％,此时降粘率达到97．50％以上。     

耐盐耐高温超稠油降黏剂的研制与性能评价*

针对超稠油黏度高、流动性差和地层水矿化度高等现状,以表面活性剂、碱、有机磷酸为原料制得乳化降黏剂,对降黏剂配方进行了优选,研究了矿化度和温度对降黏剂降黏性能的影响,并分析了降黏机理。结果表明,超稠油乳化降黏剂最优配方为:质量比为1∶1的磺酸盐类阴离子表面活性剂YBH与醇醚羧酸盐类的阴、非离子表面活性剂YFBH复配的主剂、碱助剂、耐盐助剂NYZJ-1的质量比为1.1∶0.45∶1.15。在主剂、助剂总加剂量为0.81%(占原油乳状液的质量分数)、乳化温度80℃、油水质量比为7∶3、矿化度为95 g/L的条件下,可使超稠油黏度由316.5 Pa·s(50℃)降至其乳状液的0.0831 Pa·s,降黏率达99.97%,50℃下静置4 h的出水率为5.93%。温度对乳化降黏剂降黏性能的影响较小,经200℃处理2 h后超稠油乳状液的降黏率不变。复配乳化剂各组分间发挥了协同增效作用,增强了体系的降黏性能,提高了乳状液的稳定性。乳化降黏剂降黏效果良好,耐温抗盐,适用于高温高盐油藏。图10表3参15。     

酯类化合物降低原油与二氧化碳体系最小混相压力实验

针对试验区近井地带达到混相驱、远井地带尚未达到混相驱的问题,通过注入油溶性表面活性剂(柠檬酸异丁酯或柠檬酸异戊酯)来降低原油与二氧化碳体系的最小混相压力,该表面活性剂既能够溶于原油中降低原油黏度,又能够溶解在超临界二氧化碳中降低原油与二氧化碳之间的界面张力,从而降低原油与二氧化碳之间的最小混相压力。采用长细管驱替实验的方法,测定了2种油溶性表面活性剂对试验区原油与二氧化碳体系的最小混相压力的影响。实验表明,注入的油溶性表面活性剂能够明显降低试验区原油与二氧化碳体系的最小混相压力,2种表面活性剂降低的最小混相压力值分别为7.2 MPa和6.6 MPa,并且随着表面活性剂注入段塞的增大,测得的原油与二氧化碳体系的最小混相压力逐渐降低,但是降低幅度越来越小,结合表面活性剂制备价格,得到最经济的表面活性剂注入段塞量为0.003 PV,并建议选择柠檬酸异丁酯作为试验区降低最小混相压力的化学试剂。     

胜利金家油田泡沫驱油室内研究

用阴离子、非离子和氟化表面活性剂、三聚磷酸钠、水玻璃及胜利金家油田注入水配制的起泡液，起泡能力强，形成的泡沫稳定性好，可通过乳化作用降低金家粘性原油的表观粘度。在人工填砂模型上，该起泡液与８倍体积的氮气形成的泡沫驱出了水驱残余油１６．４％，提高采收率６．９８％。     

PS降粘剂在稠油开采中的试验及应用

PS降粘机理是利用表面活性物质降低油水界面张力，促使水包油型乳状液的形成，从而降低原油粘度。PS对地层无伤害，不影响原油在地面脱水，其乳化效率高出其它表面活性剂140余倍。经国内11个油田的1000余并次应用表明：该剂性能良好，作业施工简单，投入产出比高达1：60以上。     

Effect of oil-solubility catalysts on the low-temperature oxidation of heavy crude oil

Due to low oil recovery factor in heavy oil reservoir, air injection with catalyst becomes a competitive technology to effectively reduce viscosity of crude oil as a result of the low cost and small environment pollution. This paper determined the feasibility of air injection with catalyst in a heavy oil reservoir through static and dynamic experiments. The results indicated that under the effect of catalyst, oxidation between heavy oil and air could significantly reduce the viscosity of crude oil. The optimal catalyst contained 0.7?wt. % oil-solubility organic acid copper and 0.5?wt. % sodium hydroxide. With the oxidation time increasing, viscosity of crude oil decreased and oil recovery factor increased. With temperature increasing, viscosity of crude oil decreased sharply and oil recovery factor increased. The oil recovery factor of air huff-n-puff process was 30.2%. Air injection with catalyst in the reservoir is a promising technology.