【作者】 刘芝芳；

【导师】 易绍金； 李炳金；

【作者基本信息】 长江大学 ， 石油与天然气工程， 2012， 硕士

【摘要】 大多数油藏和油气开采系统中含有的硫化氢(H2S)都是由于硫酸盐还原菌(sulfate reducing bacteria,简称SRB)的作用而形成的。SRB及其所产生的硫化氢是造成油藏开发成本高及一系列作业问题的主要原因,包括储层变酸、硫化物腐蚀、硫化铁地层堵塞、产量降低及健康、安全与环境危害。在国际石油工业中生物成因的硫化物问题特别严重,已造成了严重的经济损失。不仅增加了微生物诱导腐蚀(MIC)和有关的费用,而且生物成因的硫化物对人类健康和环境具有严重的危害。这些有害作用包括：(1)加速腐蚀和设备损坏；(2)增加设备更新费用：(3)增加购买杀菌剂的费用；(4)由于硫化铁堵塞减少产量和收益；(5)降低油气产品的价值；(6)污染环境并且对人体有害。抑制回注水中SRB的繁殖,降低腐蚀速率从而提高石油采收率,是油田回注水处理环节中亟待解决的问题。目前,油田普遍采用化学杀菌剂来控制SRB造成的危害,均取得了显著效果。但长期使用化学杀菌剂会使细菌产生抗药性,药剂用量加大,费用增高,同时也给环境带来污染负荷。近年来,生物抑制方法受到越来越多研究人员的重视。试验研究发现,当有反硝化细菌(Denitrifying Bacteria,以下简称DNB)存在时,能有效地抑制SRB的增长,大大改善设备腐蚀情况。这种现象称为生物竞争排斥(Biocompetitive Exclusion,以下简称BCX)作用,其机理是反硝化细菌(DNB)的生存环境和生存习性与SRB相似,当系统中含有一定量的硝酸盐或亚硝酸盐时,会刺激DNB的生长繁殖,将SRB还原作用替代为DNB反硝化作用,从而达到抑制SRB活性的目的。微生物提高石油采收率(Microorganism Enhances Oil Recovery,以下简称MEOR)技术是将筛选的适合地层环境的特殊微生物或它们的代谢产物注入到油藏中,通过微生物的代谢活动,将石油中长链饱和烃分解为短链烯烃,产生降解重质烃类和石蜡的酶类,产生甲烷、表面活性物质等化学物质,改变地层和原油的性能,提高采收率。本次研究是将BCX技术和MEOR技术进行有机结合,一方面控制了SRB,另一方面也达到了微生物提高石油采收率的目的。本课题通过调研长庆油田和新疆油田现有资料,考察油田地面系统中原生反硝化细菌的反硝化能力与SRB还原硫酸盐能力的相对水平,确定反硝化作用抑制硫酸盐还原作用的操作条件,并将成果应用于现场。从长庆油田采出水中分离出硫酸盐还原功能菌株,该菌株为G+,短杆状,能运动,具有硫酸盐还原功能,产H2S,严格厌氧；改变底物(投加硝酸盐)使反硝化细菌大量的繁殖,在底物竞争中,硫酸盐还原菌失去或转变其功能,导致生物活性降低,进而抑制硫酸盐还原菌的生长,实现生物的反硝化抑制。试验对反硝化的可行性进行考察,确定运行最佳生态因子。通过实验,分离、富集得到本源DNB,经初步试验本源DNB的基本特性如下：该菌种为混合菌群,菌体大小有差异,一般介于0.5-5.0μ m之间；经革兰氏染色并镜检,以G-杆菌为主,并有一定量的G+杆菌,混合菌以兼性厌氧菌为主。有氧环境不利于DNB的生长,但可存活。新疆油田采油一厂红18区块是进行聚合物驱的试验井区,由于存在大量的SRB,聚合物交联剂不能成胶,发挥不了驱油的作用。于2011年8月～11月,该种技术应用于新疆油田采油一厂红18区块。DNB菌剂及其激活剂的加入使SRB得到抑制,聚合物成胶情况良好,各井组原油产量提高。更多还原

【Abstract】 Most of the reservoir and oil/gas extraction system containing hydrogen sulfide (H2S) are due to the role of sulfate-reducing bacteria (sulfate reducing bacteria, referred to as SRB). SRB and hydrogen sulfide is caused by the high cost of reservoir development and operations of the main reasons, including the reservoirs sour sulfide corrosion of iron sulfide formation plugging, lower production and health, safety and environmental hazards. Biogenic sulfide problem is particularly acute in the international oil industry, and it has caused serious economic losses. Not only increased the microbial induced corrosion (MIC) and the related costs, but also the biogenic sulfide brought serious harm to human health and the environment. These harmful effects include:(1) accelerated corrosion and equipment damage;(2) increase in the renewal of equipment costs;(3) increase the cost to buy fungicides;(4) Due to the blockage of iron sulfide to reduce production and income;(5) to reduce oil and gas productsvalue;(6) pollution of the environment and harmful to human beings.Inhibiting the breeding of SRB in the injection water, and reducing the corrosion rate in order to enhance oil recovery, that should be the urgent problem in the oil field reinjection water treatment session. At present, oilfield commonly used chemical fungicides to control the harm caused by SRB, it have achieved remarkable results. However, long-term use of chemical fungicides make bacterial resistance, increase the amount of reagent, increased costs, and bring pollution load to environment. In recent years, the biological suppression methods take more and more researchers’ attention.The pilot study found that when the denitrifying bacteria (Denitrifying Bacteria, hereinafter referred to as DNB) exist, can effectively inhibit the growth of SRB, and greatly improve the corrosion of equipment. This phenomenon is known as bio-competitive exclusion (Exclusion Biocompetitive, hereinafter referred to as BCX) role, the mechanism is that the survival environment and living habits of the denitrifying bacteria (DNB) and SRB are similar, when the system contains a certain amount of nitrate or nitritewill, it will stimulate the growth and reproduction of DNB, the restore role of SRB is substituted by the denitrification of DNB, so as to achieve the purpose of the inhibition of SRB activity. The microbial enhanced oil recovery (Microorganism Enhances Oil Recovery, hereinafter referred to as MEOR) technology is injected the particular microorganisms screened or their metabolites that suit the stratigraphic environment into the reservoir, through the metabolic activity of microorganisms, the oil in the long chain saturatedhydrocarbon is decomposed into short-chain olefins, resulting in the enzymes of degrading heavy hydrocarbons and paraffin produce methane, surface active substances and other chemicals to change the performance of the strata and crude oil, then enhanced oil recovery. This study is the organic combination of BCX and MEOR, on the one hand, SRB is controled, on the other hand, to achieve the purpose of microbial enhanced oil recovery.This issue investigate the relative level between the denitrification capacity of the native DNB and the sulfate reduction capacity of the SRB in oilfield ground system through researching Changqing Oilfield and Xinjiang Oilfield existing information. Then determine the operating conditions for denitrification inhibiting sulfate reduction.The sulfate-reducing bacterial strain isolated from Changqing Oilfield produced water, the strain G+, short rod-shaped, motile, with sulfate-reducing function, production of H2S, strictly anaerobic; change the substrate (addition of nitrate)denitrifying bacteria in a lot of breeding, and competition of the substrate, sulfate-reducing bacteria lose or change its function, resulting in biological activity, thereby inhibiting the growth of sulfate-reducing bacteria, biological denitrification inhibition.The Xinjiang Oilfield Production Plant Hongshanzui18blocks is the polymer flooding pilot well area.The polymer crosslinking agent can not gelling and play role of flooding for the gaint amount of SRB.In August2011to November, this kind of technology applied to this blocks.DNB agents and its activator added to the polymer gelling well make the SRB to be inhibited, the production was increased of each well group.更多还原