阴离子/非离子表面活性剂驱油技术研究

对上海石油化工研究院研制的阴离子/非离子表面活性剂进行了相关方面的适用性评价,通过岩心模拟驱替实验研究了改善驱油效果的能力。评价结果表明:该表面活性剂与明15块注入水具有良好的配伍性;降低界面张力能力显著,推荐使用的浓度范围为0.05%~0.30%;地层温度条件下,可稳定65 d;65℃时经过150 min达到析水平衡且析水率仅为60%,乳化能力较好;吸附量均在2.0 mg/g左右,抗吸附能力良好。模拟驱替实验表明:使水驱采收率提高约12%,最终采收率达到42%,驱油效率显著,具有较好的经济效益。     

一种驱油用表面活性剂GY-9的制备及性能评价

通过阴离子表面活性剂(ME-3)、非离子表面活性剂(SM-2)、两性表面活性剂(AO-3)制备驱油用耐高温表面活性剂GY-9。在不同矿化度、温度下,对GY-9体系进行了油水界面张力、乳化性能、吸附性能等测试,并用长庆城95岩心进行模拟驱替实验。结果表明:体系具有较宽的温度和矿化度适用范围。在质量浓度为4.0 g/L,50 000 mg/L矿化水,模拟原油比为6∶4时,油水界面张力达到2.754×10-3m N/m数量级;当质量浓度为5.0 g/L时,界面张力可达6.7×10-4m N/m数量级,远高于行业标准。GY-9溶液的稳定性、耐温性均良好;驱替实验表明,可有效提高采收率约11.3%,在三次采油中具有极大的应用价值。     

表面活性剂HD驱油体系性能研究

在表面活性剂提高采收率原理基础上,对HD界面特性及岩心驱油实验进行了研究。结果表明,在一定条件下,HD浓度在0.025%～0.30%的较宽范围内均可使矿化度为6 823 mg/L的油田污水形成10-3mN/m数量级的超低界面张力。同时,加入适量添加剂HDSY,使达到最低界面张力的时间缩短(原来40 min,现为15 min)到原来的63.5%,且效果均优越于单一HD体系。复合体系驱替实验结果表明,在水驱含水达95%以后,还可继续提高原油采收率24.25%。     

二元复合驱化学分析及提高石油采收率技术研究

为提高二元复合驱的驱油效率,采用了一种新型的聚合物和表面活性剂组成的复合驱油剂,对其进行了化学分析及其对现场稠油的驱替效果评价。通过界面张力测量及动态界面张力分析,优选了表面活性剂PS-2作为最优选择,并确立其最优质量分数范围为0.2%～0.4%。通过黏浓特性和黏温特性实验,优选出聚合物KYPAM,并确定其最佳质量浓度为1 000 mg·L^-1。随后通过研究聚表二元复合体系的界面张力和流变性,发现该体系能够有效降低油水界面张力,并具有良好的流变性。采用单岩心驱替实验方法,对比分析了聚合物-表面活性剂二元复合驱、单一聚合物驱替及单一表面活性剂驱替对于现场高黏度原油提高采收率的效能。结果表明,聚表二元复合驱的采收率最高,达到32.1%,比水驱提高了16.2%。     

沙7区块聚/表二元体系驱油效果研究

研究了表面活性剂对原油/水界面张力、乳化作用以及对岩石润湿性的影响,开展了表面活性剂和聚合物/表面活性剂二元体系提高低渗透油藏石油采收率的实验研究。结果表明,超低界面张力是影响石油采收率的重要因素,具有良好乳化性能的驱油体系能起到更好的驱油效果,聚合物/表面活性剂二元驱油体系具有更高的提高石油采收率的效能。     

表面活性剂驱油效率的影响因素研究

在83℃下测定了3种表面活性剂DL-S、HL-Y/NNR、GZ-16的油水界面张力、乳化能力以及改变油藏岩石润湿性的能力。利用低渗透岩心驱油实验研究表面活性剂的这3种特性对驱油效率的影响。结果表明,表面活性剂的浓度在1 000 mg/L时,DL-S的油水界面张力达到10-3mN/m超低数量级,HL-Y/NNR表现出较为优越的乳化性能,GZ-16具有较好的润湿性能。在驱油实验中,具有最好乳化性能的HL-Y/NNR提高采收率的幅度最大为12.91%,其次为具有超低界面张力的DL-S,相较而言,改变润湿性的能力对驱油效率的影响最小。     

石油磺酸盐-乙二胺复合驱油体系研究

为了克服无机碱表面活性剂驱替引发结垢的问题,使用有机碱代替无机碱,与表面活性剂复配使用。以乙二胺(EDA)作为碱剂,与石油磺酸盐(SLPS)复配,研究了表面活性剂-有机胺驱油体系,优选出的体系组成为0.20%SLPS+0.15%EDA。研究了盐对体系驱替能力的影响,当氯化钠浓度低于30 000 mg/L,氯化钙浓度低于400 mg/L时,体系能使油水最低界面张力降到10^(-3) mN/m以下。考察了体系的乳化特性,随着水油体积比的减小,乳状液中值粒径逐渐变大。驱油实验表明,水驱后,该复合体系提高原油采收率达到了10.83%。     

新型表面活性剂驱油效果研究

通过对氟碳表面活性剂界面张力的研究,确定了一种用于提高原油采收率最佳的驱油体系QY-1：0．1％氟碳表面活性剂＋1600mg／L聚硅酮＋1．0％碱浓度。进行了室内静态驱油实验和岩心动态驱油实验。结果表明,驱油剂QY-1可以显著提高原油的采收率。     

阴非离子型Gemini表面活性剂驱油体系性能评价

为提高低渗透油藏采收率,开发了一种阴非离子型Gemini表面活性剂ANG7-Ⅳ-7,并测定体系的界面张力、乳化性能和吸附量。结果表明,ANG7-Ⅳ-7表面活性剂浓度在1⁴ g/L范围内,油水界面张力均可达到10-3m N/m的超低数量级,当ANG7-Ⅳ-7浓度为4 g/L时,能使油水界面张力达到最低值6.025×10-3m N/m;在注入浓度为4 g/L时,表面活性剂在油砂上的吸附量为2.035 mg/g。室内岩心驱油试验结果表明,4 g/L的ANG7-Ⅳ-7表面活性剂驱可在水驱后提高采收率11个百分点。     

阴非离子型Gemini表面活性剂驱油体系性能评价

为提高低渗透油藏采收率,开发了一种阴非离子型Gemini表面活性剂ANG7-Ⅳ-7,并测定体系的界面张力、乳化性能和吸附量。结果表明,ANG7-Ⅳ-7表面活性剂浓度在1~4 g/L范围内,油水界面张力均可达到10-3m N/m的超低数量级,当ANG7-Ⅳ-7浓度为4 g/L时,能使油水界面张力达到最低值6.025×10-3m N/m;在注入浓度为4 g/L时,表面活性剂在油砂上的吸附量为2.035 mg/g。室内岩心驱油试验结果表明,4 g/L的ANG7-Ⅳ-7表面活性剂驱可在水驱后提高采收率11个百分点。     

高30断块表面活性剂体系筛选

华北油田高30断块油藏目前已进入高含水开发后期,含水率97.0%,标定采收率仅为29.4%。当前,可大幅度提高油层波及体积和驱油效率的复合驱,是提高油藏最终采收率的有效途径和方法。已有研究表明,动态界面张力达到1-0 2mN/m数量级的复合体系的驱油效果与1-0 3mN/m数量级平衡界面张力的复合体系的驱油效果基本相当。实验表明,随着表面活性剂浓度的增加,表面活性剂/原油的界面张力逐渐降低,当界面张力达到最低值后又逐渐升高并达到平衡状态。筛选出了适合于高30断块的表面活性剂体系-0.05%石油磺酸盐CDS-1体系,该体系与原油的瞬时动态界面张力和平衡界面张力达到可以大幅度降低残余油饱和度的1-0 2~1-0 3mN/m数量级。     

Characterizations of surfactant synthesized from Jatropha oil and its application in enhanced oil recovery

Surfactants are frequently used in chemical enhanced oil recovery (EOR) as it reduces the interfacial tension (IFT) to an ultra‐low value and also alter the wettability of oil‐wet rock, which are important mechanisms for EOR. However, most of the commercial surfactants used in chemical EOR are very expensive. In view of that an attempt has been made to synthesis an anionic surfactant from non‐edible Jatropha oil for its application in EOR. Synthesized surfactant was characterized by FTIR, NMR, dynamic light scattering, thermogravimeter analyser, FESEM, and EDX analysis. Thermal degradability study of the surfactant shows no significant loss till the conventional reservoir temperature. The ability of the surfactant for its use in chemical EOR has been tested by measuring its physicochemical properties, viz., reduction of surface tension, IFT and wettability alteration. The surfactant solution shows a surface tension value of 31.6 mN/m at its critical micelle concentration (CMC). An ultra‐low IFT of 0.0917 mN/m is obtained at CMC of surfactant solution, which is further reduced to 0.00108 mN/m at optimum salinity. The synthesized surfactant alters the oil‐wet quartz surface to water‐wet which favors enhanced recovery of oil. Flooding experiments were conducted with surfactant slugs with different concentrations. Encouraging results with additional recovery more than 25% of original oil in place above the conventional water flooding have been observed. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2731–2741, 2017     

Superior enhancement of imbibition recovery by novel surfactant mixtures with a large hydrophobic group combined with nanosilica

Low interfacial tension (IFT) drainage and imbibition are effective methods for improving oil recovery from reservoirs that have low levels of oil or are tight (i.e., exhibit low oil permeability). It is critical to prepare a high efficient imbibition formula. In this work, a novel 2,4,6-tris(1-phenylethyl)phenoxy polyoxyethylene ether hydroxypropyl sodium sulfonate (TPHS) surfactant was synthesized and evaluated for imbibition. Its structure was confirmed by Fourier transform infrared spectroscopy and the interfacial tension (IFT) of the crude oil/0.07% TPHS solution was 0.276 mN/m. When 0.1 wt% TPHS was mixed with 0.2 wt% alpha olefin sulfonate (AOS), the IFT was lowered to 6 × 10⁻² mN/m. The synergy between nanoparticles (NPs) and TPHS/AOS mixed surfactant was studied by IFT, contact angle on sandstone substrates, zeta potential, and spreading dynamics through microscopic methods. The results show that the surfactant likely adsorbs to the NP surface and that NP addition can help the surfactant desorb crude oil from the glass surface. With the addition of 0.05 wt% SiO₂ NPs (SNPs), the imbibition oil recovery rate increased dramatically from 0.32%/h to 0.87%/h. The spontaneous imbibition recovery increased by 4.47% for original oil in place (OOIP). Compared to flooding by TPHS/AOS surfactant solutions, the oil recovery of forced imbibition in the sand-pack increased by 12.7% OOIP, and the water breakthrough time was delayed by 0.13 pore volumes (PV) when 0.05% SNPs were added. This paper paves the way for enhanced oil recovery in low-permeability sandstone reservoirs using novel TPHS/AOS surfactants and SNPs.     

Interfacial properties of cationic and anionic Gemini surfactant mixtures

The possibility and the prospect of cationic/anionic (“catanionic”) surfactant mixtures based on sulfonate Gemini surfactant (SGS) and bisquaternary ammonium salt (BQAS) in the field of enhanced oil recovery was investigated. The critical micelle concentration (CMC) of SGS/BQAS surfactant mixtures was 5.0 × 10⁻⁶ mol/L, 1–2 orders of magnitude lower than neat BQAS or SGS. A solution of either neat SGS or BQAS, could not reach an ultra-low interfacial tension (IFT); but 1:1 mol/mol mixtures of SGS/BQAS reduced the IFT to 1.0 × 10⁻³ mN/m at 100 mg/L. For the studied surfactant concentrations, all mixtures exhibited the lowest IFT when the molar fraction of SGS among the surfactant equaled 0.5, indicating optimal conditions for interfacial activity. The IFT between the 1:1 mol/mol SGS/BQAS mixtures and crude oil decreased and then increased with the NaCl and CaCl₂ concentrations. When the total surfactant concentration was above 50 mg/L, the IFT of SGS/BQAS mixtures was below 0.01 mN/m at the studied NaCl concentrations. Adding inorganic salt reduced the charges of hydrophilic head groups, thereby making the interfacial arrangement more compact. At the NaCl concentration was above 40,000 mg/L, surfactant molecules moved from the liquid–liquid interface to the oil phase, thus resulting in low interfacial activity. In addition, inorganic salts decreased the attractive interactions of the SGS/BQAS micelles that form in water, decreasing the apparent hydrodynamic radius (D_{H, app}) of surfactant aggregates. When the total concentration of surfactants was above 50 mg/L, the IFT between the SGS/BQAS mixtures and crude oil decreased first and then increased with time. At different surfactant concentrations, the IFT of the SGS/BQAS mixtures attained the lowest values at different times. A high surfactant concentration helped surfactant molecules diffuse from the water phase to the interfacial layer, rapidly reducing the IFT. In conclusion, the cationic-anionic Gemini surfactant mixtures exhibit superior interfacial activity, which may promote the application of Gemini surfactant.     

十八烷基己基甲基羧基甜菜碱的合成及性能

以硬脂酸和己酸为原料合成了不对称双长链烷基羧基甜菜碱——十八烷基己基甲基羧基甜菜碱(C18+6B),测定了C18+6B的表面活性,并与总碳原子数相等的对称型双十二烷基甲基羧基甜菜碱(diC12B)进行比较,以了解表面活性剂分子结构对性能的影响。结果表明,C18+6B的表面活性与diC12B基本相当,但水溶性远好于diC12B。作为无碱驱油用表面活性剂,C18+6B对大庆原油来说HLB值略偏高,45 ℃ 下单独使用能将大庆原油/地层水界面张力降至10-2mN/m数量级,在大庆油砂上的饱和吸附量比diC12B低30%。C18+6B单独能将C7~C9正构烷烃/大庆地层水界面张力降至10-3mN/m数量级,而通过与亲油性更强的diC12B以及亲水性甜菜碱复配后,能将大庆原油/地层水界面张力降至10-3mN/m数量级,并能显著改善配方的水溶性。     

十八烷基己基甲基羧基甜菜碱的合成及性能

以硬脂酸和己酸为原料合成了不对称双长链烷基羧基甜菜碱——十八烷基己基甲基羧基甜菜碱(C18+6B),测定了C18+6B的表面活性,并与总碳原子数相等的对称型双十二烷基甲基羧基甜菜碱(di C12B)进行比较,以了解表面活性剂分子结构对性能的影响。结果表明,C18+6B的表面活性与di C12B基本相当,但水溶性远好于di C12B。作为无碱驱油用表面活性剂,C18+6B对大庆原油来说HLB值略偏高,45℃下单独使用能将大庆原油/地层水界面张力降至10-2m N/m数量级,在大庆油砂上的饱和吸附量比di C12B低30%。C18+6B单独能将C7~C9正构烷烃/大庆地层水界面张力降至10-3m N/m数量级,而通过与亲油性更强的di C12B以及亲水性甜菜碱复配后,能将大庆原油/地层水界面张力降至10-3m N/m数量级,并能显著改善配方的水溶性。     

Novel surfactants for ultralow interfacial tension in a wide range of surfactant concentration and temperature

This work investigates the possibility of injecting dilute aqueous solutions of novel surfactants into the Yibal field (Sultanate of Oman). This was accomplished through an experimental protocol based on the following criteria: (i) compatibility of the surfactants with the high-saline reservoir water (∼200 g/L); (ii) low interfacial tension (IFT) between crude oil and reservoir water (less than 10⁻² mN m⁻¹); and (iii) maintaining the low IFT behaviour during the entire surfactant flooding. Novel surfactants selected in this study consist of a series of ether sulfonates (AES-205, AES-128, AES-506, and 7–58) and an amphoteric surfactant (6–105). These surfactants were found to be compatible with reservoir water up to 0.1% surfactant concentration, whereas 6–105 and 7–58 showed compatibility within the full range of surfactant concentration investigated (0.001–0.5%). All surfactant systems displayed dynamic IFT behavior, in which ultralow transient minima were observed in the range 10⁻⁴–10⁻³ mN m⁻¹, followed by an increase in the IFT to equilibrium values in the range 10⁻³–10⁻¹ mN m⁻¹. The results also showed that with respect to concentration (0.05–0.5%) and temperature (45–80°C), AES-205 and 7–58 surfactants exhibit a wide range of applicability, with the IFT remaining below 10⁻² mN m⁻¹, as required for substantial residual oil recovery. In addition, ultralow IFT were obtained at surfactant concentrations as low as 0.001%, making the use of these surfactants in enhanced oil recovery extremely cost-effective.     

Laboratory Study on the Oil Displacement Properties of Sugar Amine Sulfonate Surfactant

A sugar amine sulfonate surfactant (SAS) was used to enhance oil recovery by chemical flooding. The interfacial tension between an SAS solution and four kinds of crude oil was determined. Oil (4) containing the largest amount of medium chain length components was the most suitable candidate because the IFT could be reduced to an ultralow range (10^?3 mN/m) at optimum NaCl concentration. Emulsions consisting of oil (4) and SAS solution and the adsorption density of SAS on sandstone were studied. Compared with A37 (alkyl ether sulfate), SAS ws able to form more stable emulsions and the adsorption density was equivalent in the typical concentration range of chemical flooding. Both SAS and A37 adsorption data on sandstone followed the Langmuir isotherm model. SAS increased the apparent viscosity of KY-1500 (modified polyacrylamide) in a low concentration range and improve the viscoelasticity. A combination of SAS and KY-1500 (SP) enhanced oil recovery by 16.05 versus 14.31% (using KY-1500 alone).     

新型弱碱表面活性剂在三次采油中的应用

以α-烯烃为初始原料，经过烷基化，再经磺化、中和研制出了组分相对单一、结构合理的新型弱碱烷基苯磺酸盐表面活性剂。室内评价结果表明，该表面活性剂具有良好的界面活性，配制的复合体系在较宽的表面活性剂浓度和碱浓度范围可与原油形成10^-3mN／m数量级的超低界面张力。同时，该表面活性剂对大庆油田不同区块、不同油层的油水条件表现出了很强的适应性。另外，由于表面活性剂组成较为单一，可大大降低表面活性剂在地层中因吸附滞留而产生的色谱分离效应。室内天然岩心驱油实验表明，三元复合体系平均驱油效率可比水驱提高约20％。所开展的小井距三元复合驱矿场试验，取得了比水驱提高采收率24．66％的显著效果，为三元复合驱技术在大庆油田的工业化推广，特别是在二类油层的应用奠定了坚实基础。     

Novel fluorinated surfactants for enhanced oil recovery in carbonate reservoirs

Novel surfactant‐polymer (SP) formulations containing fluorinated amphoteric surfactant (surfactant‐A) and fluorinated anionic surfactant (surfactant‐B) with partially hydrolyzed polyacrylamide (HPAM) were evaluated for enhanced oil recovery applications in carbonate reservoirs. Thermal stability, rheological properties, interfacial tension, and adsorption on the mineral surface were measured. The effects of the surfactant type, surfactant concentration, temperature, and salinity on the rheological properties of the SP systems were examined. Both surfactants were found to be thermally stable at a high temperature (90 °C). Surfactant‐B decreased the viscosity and the storage modulus of the HPAM. Surfactant‐A had no influence on the rheological properties of the HPAM. Surfactant‐A showed complete solubility and thermal stability in seawater at 90 °C. Only surfactant‐A was used in adsorption, interfacial tension, and core flooding experiments, since surfactant‐B was not completely soluble in seawater and therefore was limited to deionized water. A decrease in oil/water interfacial tension (IFT) of almost one order of magnitude was observed when adding surfactant‐A. However, betaine‐based co‐surfactant reduced the IFT to 10^?3 mN/m. An adsorption isotherm showed that the maximum adsorption of surfactant‐A was 1 mg per g of rock. Core flooding experiments showed 42 % additional oil recovery using 2.5 g/L (2500 ppm) HPAM and 0.001 g/g (0.1 mass%) amphoteric surfactant at 90 °C.