College of Life Sciences,Nankai University
为了满足油田采出液破乳需求,同时减少常规油田化学剂对环境的污染,本文根据新疆玛东区块存在页岩油压裂采出液复杂情况,在满足环境安全的基础上,利用瓶试法对十五种通过微生物发酵合成的生物破乳剂进行筛选评价,同时对菌发酵液和纯化提取物进行了破乳对比,结果显示XJ-4菌所合成的生物破乳剂XJ-4-2对玛东区块采出液有很好的配伍性和80%以上的脱水率。为了提高破乳效率和降低成本,采用了生物破乳剂和常规化学破乳剂的复配体系,经过优化生物破乳剂XJ-4-2与化学聚醚类破乳剂的复配体系的破乳效率达到95%以上。通过投加工艺的优化,初始含水率为43.76%,在60 ℃下,加入化学破乳剂200mg/L时,沉降2h后脱水率为91.45%,脱水原油含水率为8.43%,污水含油率228mg/L；改进后原油初始含水率为33.85%,在50 ℃下,加入复合配方200mg/L时,热化学沉降2h后脱水率为94.56%,剩余原油含水率为1.84%,污水含油率156mg/L。综上所述,生物破乳剂在低温下脱水率高、污水含油率低,对玛东区块含页岩油压裂开采采出液的高效分离、保证油田的正常运行和经济效益具有重要意义。
In order to meet the demand for demulsification in Xinjiang oilfields, and reduce the environmental pollution of common oilfield chemicals, this article based on environmental safety and the complex situation of shale oil fracturing produced fluids in the Madong block in Xinjiang, and fifteen kinds of biodemulsifiers synthesized by microbial fermentation were screened and evaluated by the bottle test method. The demulsification of the fermentation broth and the purified extract was compared, and the results showed that the biodemulsifier XJ-4-2 synthesized by the XJ-4 bacteria had good compatibility with the extracted fluid from the Madong block and more than 80% dehydration rate. In order to improve the demulsification efficiency and reduce the cost, a composite system of biological demulsifier and conventional chemical demulsifier is adopted. After optimization, the demulsification efficiency of the composite system of biological demulsifier XJ-4-2 and chemical polyether demulsifier reaches above 95％. Through the optimization of the dosing process, the initial water content is 43.76%. When the chemical demulsifier 200mg/L is added at 60 ℃, the dehydration rate after 2h sedimentation is 91.45%, the remaining water content ratio of crude oil was 8.43%, and the oil content ratio of sewage is 228mg/ L. The initial water content of the improved crude oil is 33.85%. At 50 ℃, when the compound formula 200mg/L is added, the dehydration rate after 2h sedimentation is 94.56%, the remaining water content ratio of crude oil 1.84%, and the oil content ratio of sewage is 156mg/L. In summary, the biological demulsifier has high dehydration rate at low temperature and low sewage oil content. It is of great significance for the efficient separation of produced fluids from fracturing exploitation of shale oil in the Madong block and ensuring the normal operation and economic benefits of the oilfield.