聚驱后阳离子聚合物HCP提高采收率机理研究

A Mechanistic Study on Enhanced Oil Recovery by Cationic Polymer HCP after Polymer Flood Finished

对胜利孤岛聚驱后油藏阳离子聚合物HCP驱油效果和机理进行了实验研究。HCP为用环氧丙基三甲基氯化铵醚化的淀粉。实验溶液用矿化度5．1g/L的模拟油田污水配制，驱替用HPAM溶液浓度1．2g/L，室温黏度10．1mPa·s，HCP溶液浓度8g／L，室温黏度7．8mPa·s。0～20g/LHCP溶液70℃下与孤岛中二南脱气原油（黏度121．8mPa·s）间的界面张力为11．3～8．87mN／m，室温下使油湿、弱水湿矿物表面接触角变小，亲水性增强；HCP与HPAM溶液相混时产生白色絮状沉淀，质量比为10：1时沉淀量最多。在渗透率0．29～1．00μm^2的含黏土石英砂肢结岩心中注入1PV0．2～1．2g/L的HCP溶液，使水相渗透率降低58．4％～94．0％。采用表面弱油湿的石英砂填充可视化平面模型，用黏度52．46mPa·s的模拟油驱替至束缚水饱和，在水驱、聚驱（0．3PV）、后续水驱（0．2PV）之后注入HCP溶液，观测到残余油启动，形成富集油带，波及面积扩大至几乎全模型。采用渗透率5．1和1．2μm^2的储层砂充填管并联模型和70℃黏度73mPa·s的模拟油，按相同程序完成后续水驱后注入0．3PVHCP溶液并水驱，高、低渗管和全模型采收率增值分别为3．26％、4，84％、4．04％，在相同条件下改注0．4PV超低界面张力表面活性剂体系并水驱，相应的采收率增值仅分别为0．74％、1．56％、1．15％。图2表4参9。

Through screening, rescreening, acclimation, rejuvenation, and enrichment by the way of mixing the culture with inorganic nutrients and crude oils, cultivating the mixture at 37℃ in 3 days and investigating the emulsification/dispersion of viscous oils, several bacterial strains are obtained for use in EMOR in heavy oil reservoirs of blocks Jing-45 and Qian-12, Liaohe, and evaluated for their properties. Composed of two or more colonies, these bacteria maintain activity in passage from generation to generation, grow well on liquid paraffin and crude oils as carbon source, on inorganic and organic nitrogen compounds as nitrogen source and on phosphates as phosphorus source, produce surfactants and acids as shown by the surface tension and pH value of the froth and degrade heavy oils more notably at aerobic conditions than at anaerobic conditions with oil viscosity decreased by some 20%. The selected bacterial strains, 11, Lj1, and 21, in cultures of bacterial population 〉 10^4 cell/mL possess good emulsifylng/dispersing capacities for heavy oils. On 13 steam huff-puff （SH-P） wells of Jing-45 and Qian-12 reservoirs, characterized by high water cut, low oil productivity, low steam stimulating efficiency and high cycles of steam injection reached, field trials on microbes huff-puff （MH-P） of first cycle have been performed with treating radius 3 m, volume of broth injected per well 2.1-9.8 m^3, and downhole fermentation time no less than 7-9 days. In comparison with the last cycle of SH-P, MH-P trials in 12 wells are effective： a raise in oil output observed in 6 wells and a drop in oil output but a beneficial economic input-to-output ratio-in another 6 wells. On 6 of these 12 wells, the second cycle of MH-P has been conducted after the microbial population in produced water decreased down to 10^4 cell/mL. The operations and results of MH-P on 2 wells are presented in some deiail and on one well of the 2 the second cycle of MH-P is reached. The oil-to-steam ratio in MH-P is determined using cost ratio of microbes to steam instead of mass of steam injected and is named as ＂pseudo oil-to-steam ratio＂.