油水过渡带薄浅层特稠油微生物开发技术——以准噶尔盆地西缘春风油田为例

Microbial enhanced oil recovery of oil-water transitional zone in thin-shallow extra heavy oil reservoirs:A case study of Chunfeng Oilfield in western margin of Junggar Basin,NW China

为了改善准噶尔盆地西缘春风油田油水过渡带薄浅层特稠油开采效果,以油水过渡带P6-P48井为例,开展了微生物采油技术研究。P6-P48井蒸汽吞吐开采初期由于边水侵入造成高含水关井,分析认为其油藏条件适合采用微生物冷采技术。根据P6-P48井油样组成,筛选内源微生物菌种芽孢杆菌XJZ2-1、假单胞菌XJZ3-1、迪茨氏菌Z4M8-2,外源微生物菌种芽孢杆菌SLG5B10-17,营养液及激活剂。根据近井地带处理半径,设计微生物注入方案,2014年9月注入微生物菌液+营养液及激活剂865 m3后关井反应166 d,2015年3月15日开井生产,至2016年4月30日已生产405 d,产油3 464 t。微生物采油后50℃脱气原油黏度下降了58%,采出液中检测出了注入的活菌,且数量较多,表明注入菌菌种适应地层条件并生长繁殖。与16口蒸汽吞吐的邻井相比,微生物采油有效期长且具有更好的经济效益。微生物采油用于P6-P49和P6-P47井也取得较好的效果。

To improve the production effect of oil-water transitional zone in thin-shallow extra heavy oil reservoirs of Chunfeng Oilfield in western marginal area of the Junggar Basin, microbial enhanced oil recovery was studied taking the P6-P48 well of the oil-water transitional zone as an example. In the early stage of steam stimulation, the P6-P48 well was shut-in due to high water cut caused by edge water incursion, and analysis showed that its reservoir conditions are suitable for microbial cold production technology. According to the P6-P48 well oil sample composition, the study screened indigenous microbe strain of bacillus X J2-1, aeruginosa X J3-1, Dietz＇s bacteria Z4M8-2, inoculating microbes strain of bacillus SLG5B10-17, nutrient solution, and activator; and designed microbial injection scheme according to near borehole zones treatment radius. In September 2014, 865 m^3 of microbial bacterial liquid, nutrient solution and activator was injected and the well was shut in for 166 d of reaction time. The well-hole was opened to produce in March 15, 2015, and has produced 405 d until April 30, 2016, producing oil 3 464 t. The 50℃ degassing crude oil viscosity was decreased by 58% after microbial enhanced oil recovery, and the injected live bacteria was found in produced fluid, with more quantity, indicating that the injected bacteria are adaptive and has reproduced in formation condition. Compared with 16 adjacent wells of steam soaking, microbial enhanced oil recovery has long valid period and better economic benefit. Microbial enhanced oil recovery also got good results in the P6-P49 and P6-P47 wells.