低/超低渗透油田提高微生物驱油效率的基因重组优化研究

As a significant method in low/ultra low permeability oilfield water flooding development, Microbial enhanced oil recovery technology(MEOR) has been widely studied because of its low cost, simple processed, well-adapted, few damage to the production layer and environmental friendly. However, the unstability of functional strain makes the MEOR application has not been widely used. This study takes the field tests of microbial oil displacement at the 9 reservoir of Jurassic Yan’an formation at Jianshan oil field in Ordos Basin as the background. Through the analysis of geological data, dynamic data of oil and water wells, test data, monitoring data on microbial quantity and metabolic level, studied on microbial flooding in low permeability oil field, selecting well and layer selection conditions, the structure of the original flora in oil reservoir, screening of high efficiency oil displacement functional bacteria, construction of engineering bacteria and its application in the field. The method was based on the second-generation sequencing technology(Illunina) to identify the microbial flora and use multiple physiology and biochemistry experiments to select the target strain(s). Utilize the gene engineering and proteomics methods to modify and develop the functional activities via the expression of rhamnolipid transferase and alkane degrading enzyme in host strain for enhancement of the lipopeptide biosurfactants and petroleum degradation effects. In order to strengthen the high temperature/high pressure resistance of the target strain(s), the formate dehydrogenase, chitinase-like enzyme and receptor kinase has been integrant into the host cell’s genome.

微生物驱油技术作为低/超低渗透油田中后期强化采油技术的重要手段，因价廉、普适、不伤害产层而具潜力。目前理论和技术的不完备性及其效果的不稳定性，成为难以大面积推广的主要问题。本研究以鄂尔多斯盆地典型低/超低渗透侏罗系延9油层为微生物驱油现场试验背景，在MEOR功能菌筛选、驱油机理和地下菌群结构的研究基础上，充分考虑地质影响因素和选井选层原则，对微生物驱油规律、油藏本源菌群结构、高效驱油功能菌筛选、高活性驱油功能菌株的基因工程构建以及微生物驱油工艺优化等方面进行系统的研究。拟使用第二代测序（Illunina）对本源驱油微生物进行鉴定和筛选，将外源鼠李糖脂转移酶和烷烃降解酶进行受菌体表达，确认脂肽类表面活性与石油降解效能的提高效果；通过表达甲酸脱氢酶、类几丁质酶和类受体激酶提升菌株耐高温高压性能，确保驱油菌株的高存活率和高活性。该申请项目有望较大幅度提高油田采收率，并为类似油田开发中微生物驱油应

本项目旨在针对致密油和稠油的开发，在优化条件下提高微生物得驱油效率，在未来工业应用过程中具有重要的科学意义和较大的经济价值。具体研究成果如下：.（1）对低渗透油田微生物驱油规律和地质影响因素进行了分析，探索了低渗透油田微生物驱油技术选井选层条件创造有利条件；对72组原油样品和66组采出水样品进行测序对比，共检测出1152种不同种属微生物，分属于19个门54个纲112个目176个科243个属。.（2）对该油田侏罗系延9储层进行油藏微生物菌群结构分析，得到该层位的微生物生态系统多样性；.（3）从12个不同深度油井单元样品中分离出16株高效驱油功能菌，对其主要性能测试得出，以原油为唯一碳源得情况下可有效降低原油粘性66.6%~81.3%，并且可对高温高盐环境有良好的适应性。.（4）经过GC-MS对原油中饱和烃组分进行分析，得知A-3、SC4561、SC4534(2)三菌株对长链（C22-C35）的正构饱和烃有较好的降解效果。JSC4501、I-1、SC4542对C14前的短链有一定的消耗，而C14之后的烷烃含量均有所上升。但其针对异构烷烃如三环、四环萜烷、藿烷的利用效果较好。直链烷烃比例的上升可能是由于环烷烃解环而形成了直链的烷烃。

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