内源微生物驱油及其对油藏微生物活动的影响

【目的】新疆油田六中区为典型水驱普通稠油油藏，水驱效果较差，油藏具有丰富的内源微生物，本研究通过分析内源微生物驱油对油藏微生物活动的影响，确定内源微生物驱油技术在该类油藏的应用潜力。【方法】采用高通量测序及分析化学技术，系统研究实施内源微生物驱油技术后油藏细菌群落结构组成、细菌总数和功能菌群的浓度以及采出液的流体性质，总结内源微生物驱油对油藏微生物活动的影响。【结果】现场试验注入激活剂和空气后，内源微生物被显著激活，细菌群落结构发生明显变化，细菌总数及功能菌群浓度普遍提高了2–3个数量级；各种内源微生物代谢活动显著增强，与地层流体相互作用后，原油明显被乳化，最终石油采收率提高5.2%。【结论】对于内源微生物较为丰富的水驱普通稠油油藏，内源微生物驱油技术对油藏微生物活动的影响显著，具有显著的技术优势和较大的应用潜力，微生物群落结构、功能菌群浓度及其相关代谢产物可以作为评价内源微生物驱油现场激活效果的重要指标，为其他内源微生物驱油现场试验提供技术参考。     

高温高盐油藏内源微生物室内模拟激活

胜利油田永8区块原油黏度高、水驱效果差,而且受该区块高温高盐油藏条件影响,常规化学驱技术难以有效提高水驱效率,针对此类问题,笔者开展内源微生物驱油技术研究。内源菌群分析表明,该区块油藏具备了产生物乳化剂、产甲烷气等几种主要功能菌群的条件。筛选并优化出能有效激活内源菌群的激活剂配方。经过激活后微生物的有效浓度达到10~8个/m L以上,产气压力达到0.088 MPa,最大产气速率达到0.2 L/(g·d)(以1 g激活剂计),柴油乳化指数达到100%,乳化效果48 h内稳定。室内物模驱油评价表明,注入该激活剂配方0.3 PV(孔隙体积)后可提高采收率9%以上,含水率由95.1%下降到81.4%,表现出了良好的应用潜力,为下一步在高温高盐油藏开展微生物驱提供了依据。     

中高温油藏内源微生物驱油现场试验

针对胜利油田中高温油藏地质、开发情况及内源微生物群落特点,从中高温(55~85℃)油藏605个单元中选定沾3块为目标油藏区块,采用现场分阶段、逐步推进的方式实施微生物驱油试验。现场试验跟踪分析效果表明,对应油井产量从38.9 t/d升高到86.9 t/d,含水率从93.8%下降到89.1%;截至2016年3月,累计增油3.76万t,阶段提高采收率1.73%。沾3块油藏内源微生物被有效激活,油藏微生物多样性显著降低,与现场动态变化吻合。     

新型稠化缓释营养剂的优化及其驱油潜力评价

基于当前内源微生物驱油技术研发和矿场应用现状,开发能够提供并延缓释放微生物营养、调堵高渗透层双重作用的新型激活剂体系,从而解决内源微生物驱油过程中营养剂随驱替液过快采出的问题。物理模拟驱油实验表明,该稠化缓释营养剂能够显著激活内源微生物和功能菌群,使总体菌密度提升2~3个数量级,并联填砂管岩心驱油效率提高21.8%,单只岩心最大提高约53.7%,具有较强的应用潜力。该研究对內源微生物驱油技术的应用具有参考价值。     

油藏微生物的代谢特征与提高原油采收率技术

油藏是一个高温、高压、少氧、寡营养和封闭的极端环境,油田经过多年注水开发后,在油藏内部形成了相对稳定的微生物群落体系,这些微生物以石油烃分解为起始,形成了一个复杂的食物链,对油藏碳、硫和金属离子的元素地球化学循环起着非常重要的作用。微生物提高原油采收率技术(MEOR)是利用微生物及其代谢产物与油藏和原油发生作用来提高原油采收率的一种新技术,具有成本低、适应性强和环境友好等特点,因此有望成为未来化学驱后油藏和高含水油藏进一步提高采收率的重要手段。对油藏内源微生物及其介导的生化反应,微生物采油原理、发展历程和现场试验进行综述,并提出了未来的发展方向。     

微生物采油技术用于聚驱后油藏的研究进展

聚合物驱后仍会有大量的剩余油残留在低渗透层中,而且油层中滞留的聚合物还会给后续的驱油带来负面影响。有很多证据表明,在聚驱油藏中、聚驱油田产出液中、油田土壤中,存在能降解常用驱油聚合物,并以之为唯一营养源的细菌。这样人们就可以利用微生物的降解作用除去油藏中残留聚合物,再结合常规微生物采油技术进一步提高聚驱后油藏的采收率。目前已经进行的室内、现场实验取得了一定成效,但有明显局限性。不过通过进一步的理论研究,大部分问题会得到解决,所以该技术的发展前景仍然广大。     

复合驱油菌系的构建及驱油性能测定

目的利用不同驱油功能菌株构建有效复合驱油菌系。方法对不同组合的驱油菌系分别进行石油降解实验、乳化实验、表面张力测定以及岩心驱替实验等。结果通过实验得到一组复合驱油菌系,在岩心驱替实验中将采收率提高了9.6%。结论通过实验构建复合驱油菌系,得到其最佳配比以及最佳菌种比例,可有效提高石油采收率。     

模拟油藏条件下内源微生物群落空间分布规律

【背景】油藏内源微生物群落是开展内源微生物驱油技术的物质基础,由于油藏多孔介质取样技术难度大、成本高,实施内源微生物驱油后从注入端到产出端多孔介质中的内源微生物空间分布规律尚不明确。【目的】通过室内长岩心连续驱替实验模拟油藏内源微生物驱油过程,分析实施后不同空间位点油砂上吸附的内源微生物群落结构,揭示从注入端到产出端内源微生物群落的空间分布规律。【方法】借助高通量测序技术及荧光定量PCR技术解析不同空间位点油砂原位微生物群落信息。【结果】注入端到产出端不同空间位点生态环境的差异及菌属间的相互作用造成油藏内源微生物群落空间分布差异,存在明显的好氧、厌氧空间演替变化规律。岩心前端主要存在一些好氧类的产生物表面活性剂类微生物如假单胞菌属,岩心中部主要存在兼性和厌氧类的微生物如地芽孢杆菌、厌氧杆菌属,岩心末端主要分布严格厌氧类细菌和产甲烷古菌,厌氧类微生物代谢产生的H2、CO2和乙酸分子可以为产甲烷古菌提供代谢底物。【结论】通过室内物模油砂研究,首次明确了内源微生物群落在多孔介质中从注入端到产出端的空间分布规律,证实油藏内源微生物的好氧、厌氧空间接替分布规律,深化了对油藏内源微生物的认识。     

内源微生物驱油过程中营养激活体系的优化

为了进一步提高内源微生物驱油效果,针对邵家油田沾3区块的1口注入井和4口油井分别开展不同种类的内源微生物营养激活体系评价实验。依据营养体系激活的菌体密度、产气量和原油乳化效果,对现有营养体系进行筛选优化。结果发现:最佳的营养体系为3g/L植物多糖,1g/L玉米浆干粉,2g/LNaNO_3,0.2g/L(NH_4)_2HPO_4。在该营养激活剂体系下,激活菌的密度大,达4×108个/mL,激活后产生的生物气可达到0.108MPa,原油采收率比原有体系提高2.8%,同时产出液中乙酸质量浓度上升至600mg/L,注入水的表面张力降低至34.1mN/m。     

中高温油藏内源微生物厌氧激活

为了明确中高温油藏内源微生物厌氧激活产气的特点,在胜利油田选取了11个区块开展产气研究,温度范围分别为55~65℃、65~79℃、79~95℃。在模拟油藏条件下厌氧激活发现,低于79℃时,油藏内源微生物普遍能被激活并代谢产气;而高于79℃时,无明显甲烷气产生。利用不同碳源激活后发现,H_2/CO_2为碳源时,最大产甲烷速率可达1 500μmol/(g·d),显著高于乙酸钠和淀粉,这表明中高温油藏内产甲烷古菌以氢营养型为主。进一步对正理庄正南区块内源微生物群落组成研究,发现厌氧激活后古菌中Methanobacterium被激活成为优势菌群,有利于在油藏内代谢产甲烷气。厌氧激活前油水样中优势菌都是Pseudomonas,不同激活剂条件下优势菌群发生明显变化,H2/CO2和淀粉以激活Thermotoga为主,而乙酸钠则主要激活了油井中的Deferribacter。此外,该区块不同油井在相同激活条件下,其优势菌群趋向于一致,但油井和水井中优势菌群存在明显差异。通过对中高温油藏内源微生物厌氧激活的研究,为进一步提高微生物采油的效果奠定了基础。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.