【作者】 郝春雷；

【导师】 刘永建；

【作者基本信息】 大庆石油学院 ， 油气田开发工程， 2009， 博士

【摘要】 采用聚合物驱油的油田,当采收率无法进一步提高时,其油藏中不仅有近一半的剩余油,而且还有部分聚合物被吸附和滞留在岩石孔隙中。这不但降低了油藏渗透率,而且限制了后续驱油剂的作用效果,使剩余油很难开采。学术界和油田生产部门普遍认为,解决聚驱后油藏的开采问题具有很高的学术价值和现实意义。本文正是针对这个问题,开发出一种微生物驱油方法,为延长聚驱后油田的生产周期提供一个新的选择方案。本文筛选到4株聚合物降解菌种:JHW-1、JHW-3、JJF、JJH,它们分别属于芽孢杆菌属、梭状芽孢杆菌属、假单胞杆菌属、芽孢杆菌属。在45℃,pH6.0～8.0条件下,在以聚合物为唯一营养源时,4株降解菌可将聚合物粘度减小37%～52%(JHW-3降粘能力最强),由4株降解菌组成的复合菌降粘率为61%左右。聚合物培养基中加入蔗糖后(最终浓度为2g/L),4株聚合物降解菌的降粘率增至56%～92%,复合菌种的降粘率达到97%左右。4株降解菌都能产生水解酶水解聚合物,JHW-1、JHW-3和JJF能产生一种或几种降解辅助蛋白组分,它们同水解酶共同作用于聚合物时可将聚合物降解。如果以聚合物和葡萄糖或蔗糖物质为营养源,JHW-1和JHW-3还能产生新的辅助蛋白组分进一步提高降解性能。JHW-1、JHW-3和JJH产生的非蛋白产物具有还原性,它们能促发自由基氧化还原反应,进而导致聚合物碳链断裂,但它们不能水解聚合物。聚合物被微生物降解后,酰胺基团被大量水解,产生羧酸以及羧酸根基团,该过程可能是导致聚合物主链断裂的一个因素。葡萄糖或蔗糖存在时,菌种水解性能会显著地提高。本文对能以原油为营养源,并代谢表面活性剂的驱油菌种—T11进行了功能测定。在最适条件下,如果在原油培养剂中添加蔗糖和硝酸铵,则T11可使原油粘度可由64mPa·s降至34mPa·s左右。岩心中注入T11菌液45℃培养7d后,采收率可比单纯水驱提高10%～11%。T11代谢产生的生物表面活性剂为鼠李糖脂类物质,最大产量为1080 mg/L,表面活性剂样品的临界胶束浓度为39.3mg/L。T11可与JHW-3通过原生质体融合技术进行融合,获得的融合子本文命名为CZ-7,其生长条件同其亲本没有明显差别。45℃,pH7.0条件下,在聚合物原油培养基中添加1.0mg/mL蔗糖时,接种CZ-7培养7d,可使聚合物分子量从18×106降至0.6×106。溶液表面张力由57.7mN/m降至28.6mN/m;原油粘度由55.2mPa·s降至30.3mPa·s。重组菌的活性整体上要超过两亲本菌株组成的复合体系。重组菌CZ-7同JHW-1、JJF、JJH、T11复配,组成复合菌后,其降解聚合物、产表活剂、降低原油粘度的能力都较不含CZ-7时有明显提高,本文将该复合菌命名为ZH-3。CZ-7在外来营养成分不足时能进一步降低聚合物的分子量,并产生表活剂,促进复合菌中其他菌株的生长,进而提高了ZH-3的性能。本文研究表明:岩芯长时间注入聚合物后,注入ZH-3菌液培养,可使渗透率得到部分恢复。注入0.4PV、蔗糖浓度为1.0g/L的ZH-3培养液段塞,45℃培养7d,可使采收率较聚驱后继续提高6.5%,使原油粘度由64.7 mPa·s降至42.6 mPa·s。研究结果还表明,CZ-7的存在可使ZH-3岩心实验结果更加稳定。在非均质岩层中,ZH-3菌能更多地采出低渗透地层中的残余油;当渗透率级差增大时,采收率提高幅度相对较小。文中还针对大庆萨北过渡带重质原油,研究了微生物驱油的可行性,结果表明该区块重质原油油藏适宜应用微生物采油。地层水中所含的营养物质少,须选用无机盐含量和种类较多的污水配制注入菌液,现场接种的活菌量应大于106个/mL。更多还原

【Abstract】 When recovery could not be improved in oil field where polymer was used, much oil remained in reservoir, and some polymer was adsorbed and left in rock pore. The left polymer would depress permeability of reservoir, moreover it could confine the impact of post displacement agent. The polymer used at chinese oilfield almost is polyacrylamide (PAM), which was not degraded hard and its viscosity was great in reservoir. It was figured in academe that microbe is able to degrade remaining polymer in reservoir. Therefore, it should be significative for stable production of oilfield, that new strain able to degrade remaining polymer and flood is screened, cultivated and constructed, and was applied at oilfield after polymer flooding afterward.Four strain of bacteria degrading polymer were screened: JHW-1,JHW-3,JJF and JJH, which belongs to bacillus spp, clostridium spp, Pseudomonas spp and bacillus spp respectively. Under the condition of 45℃,pH6.0～8.0, 4 degrading bacteria could decrease viscosity of polymer 37%～52%, and compound bacterium composed of 4 degrading bacteria could reduce viscosity of polymer about 61%, when polymer became exclusive nutrient source. After sucrose was added to polymer culture medium, 4 degrading bacteria could lessen polymer viscosity 56%～92%, and the compound bacterium debase polymer viscosity 97% around.All 4 degrading strains can produce hydrolase to hydrolyze polymer, and JHW-1、JHW-3 and JJF are able to secret one or a few kind of aiding degrading protein components, which are capable to degrade polymer with hydrolase. JHW-1and JHW-3 would release new aiding degrading protein components to improve degradation performance more, while polymer and glucose or sucrose act as nutrient source. The nonprotein product from JHW-1、JHW-3 and JJH is reducing and capable to promote free radical redox reaction that would make polymer carbon chain rupture, but the product could not hydrolyze polymer. Amide group of polymer degraded could be hydrolyzed much to carboxylic acid and carboxylic ion, which could be a factor leading polymer carbon chain rupture. Hydrolyzing capability of strains would rise evidently,when glucose or sucrose exist in culture medium.A strain of MEOR bacterium, T11, which was capable to release surfactant and looked upon crude oil as nutrition, was determined in this paper. T11 could lower viscosity of crude oil from 64 mPa·s to 34 mPa·s, when sucrose and NH4NO3 contain in crude oil culture medium, under the optimum conditions. When T11 was infused to core and cultured for 7d, recovery would arise 10%～11% than that water flooding. Biosurfactants produced by T11 is detected as rhamnolipid, whose the most yield reaches 1080 mg/L and critical micelle concentration is 39.3mg/L.Fusant, CZ-7, was gained through protoplast fusion between JHW-3 and T11, and its growth condition had no evident distinction compare with the parents. CZ-7 had been cultivated in polymer crude oil culture medium containing 1.0mg/mL sucrose for 7 d, so polymer molecular weight would drop from 18×106 to 0.6×106, and surface tension of culture medium would fall 57.7mN/m to 28.6mN/m, moreover crude oil viscosity would decrease to 30.3mPa·s from 55.2mPa·s, under the condition 45℃,pH7.0. The capability of CZ-7 excesses that of the compoud system containing two parents on the whole.The compound bacteria that CZ-7 had been remixed with JHW-1、JJF、JJH、T11 was named with ZH-3, which had higher capability of degrading polymer, producing surfactant, reducing crude oil viscosity than that had no CZ-7. CZ-7 could degrade polymer and produce surfactant even no adeguate nutrition component, and promote other strains growing, which enhanced the capability of ZH-3.ZH-3 was injected into core and cultured, which would resume core permeability partly, after polymer flooding a long time. Recovery would improve 6.5% compare with polymer flooding, and crude oil viscosity would turn 42.6 mPa·s from 64.7 mPa·s, after ZH-3 culture medium slug that 0.4PV with 1.0g/L sucrose was infused into core and had cultivated for 7d. In heterogeneous strata, ZH-3 would displace more remaining oil in Low Permeability Formation; recovery increased range would turn lower, when permeability ratio augmented.Crude oil belong to heavy crude in Daqing Sabei transitional zone, where MEOR could be implemented. Nutrition substance was little in stratum water, so injeced bacterial liquid should be confected with sewage having much inorganic salt, and living cell concentration should be higher than 106 /mL in field test.更多还原