摘要
对于长庆油田低渗高矿化度油藏，空气泡沫复合驱提高采收率是可行、有效的方法。本文评价了高矿化度地层水、原油等地层介质对8种起泡剂发泡性能、稳泡性能的影响；起泡剂对原油和高矿化度地层水的表面张力和黏度的影响。这8种起泡剂分别为高级醇聚氧乙烯醚硫酸钠，椰油酰胺丙基二甲胺乙内酯，十二烷基苯磺酸钠，辛基酚聚氧乙烯醚（TX-10），烷基酚聚氧乙烯醚（OP-10），椰子油烷醇酰胺6501，醇醚羧酸盐，FLH非离子渗析剂，依次按1~8编号。长庆油田注入水水型Na2SO4，矿化度1.1 g/L，pH值6.5；地层水水型CaCl2，矿化度82.2 g/L，pH值5.95；原油密度0.85 g/cm3，黏度6 mPa·s。结果表明，6~8号起泡剂与长庆油田地层水不配伍。1~5号起泡剂使注入水和地层水的表面张力降低一半，对原油表面张力和黏度无影响。将配液用水由注入水改为体积比1:1的注入水、地层水混合水后，1~5号起泡剂的泡沫体积变化较小，3~5号起泡剂的泡沫半衰期没有变化，1号起泡剂泡沫半衰期由70增至260 min，2号由60降至25 min。在5% 1号起泡剂溶液中加入1%原油，泡沫体积由398降至388 mL、泡沫半衰期由70降至7 min，洗油能力较好。1号起泡剂高级醇聚氧乙烯醚硫酸脂钠符合长庆油田空气泡沫驱的要求。
Abstract
Air foam complex flooding used to improving oil recovery was feasible and effective method in low permeability and high salinity reservoir of Changqing oilfield. The effect of strata medium, such as high salinity formation water and oil etc, on the foaming and steady performance of eight foaming agents, and the effect of foaming agent on the surface tension and viscosity of crude oil and high salinity formation water were evaluated. The eight different foaming agents were sodium alcohol ether sulphate, cocoamidopropyl betaine, sodium dodecyl benzene sulphonate, octaphenyl polyoxyethyiene (TX-10), alkylphenol ethoxylates (OP-10), coconutt diethanol amide 6501, alcohol ether carboxylate, FLH nonionic osmotic agent, which were numbered consecutively from 1 to 8. The injected water type of Changqing oilfield was Na2SO4, with 1.1 g/L salinity and 6.5 pH value. The formation water type was CaCl2 with 82.2 g/L salinity and 5.95 pH value. The density of crude oil was 0.85 g/cm3, and the viscosity was 6 mPa·s. Experiment results indicated that No. 6—8 foaming agents were not compatibility with formation water. No. 1—5 foaming agents reduced the surface tension of injected water and formation water by half. And there was no influence on surface tension and viscosity of crude oil. When injected water was changed to a combination of injected water and formation water in volume ratio 1:1, the foam volume of No. 1—5 foaming agents changed a little, and there was no change of foam half-life of No. 3—5 foaming agents. The foam half-life of No. 1 foaming agent increased from 70 to 260 min, and that of No. 2 decreased from 60 to 25 min. After 1% crude oil was mixed with 5% No. 1 foaming agent solution, the foam volume reduced from 398 to 388 mL, and the foam half-life decreased from 70 to 7 min, showing good washing oil ability. No. 1 foaming agent sodium alcohol ether sulphate satisfied the requirement of air foam flooding in Changqing oilfield.
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