陕北地区油气田钻井混合废弃物的微生物原位修复技术研究

【作者】 陈立；

【导师】 陈五岭；

【作者基本信息】 西北大学 ， 微生物学， 2009， 博士

【摘要】 钻井混合废弃物是指在油气开采过程中所有固液废弃物的混合体。主要由钻井废弃泥浆、废弃钻井液、钻井废水、钻屑及压裂作业返排液等组成,是一种含粘土、加重材料、各种化学试剂、污水、污油及钻屑等的多相稳定悬浮胶体体系,是石油天然气勘探开发过程中影响生态环境的主要废弃物之一。本研究采用现代微生物工程技术原理,针对陕北地区油气田钻井混合废弃物中有害成分,选育具有高效降解转化能力的微生物复合菌群,研究开发出复合固体菌剂对混合废弃物进行微生物原位修复。通过微生物菌群的生长代谢作用,创新的解决了混合废弃物的脱毒、脱胶、固液分离、降低酸碱度等难题,使钻井混合废弃物达到无害化处理的目的,保护了油气田井场的生态环境。从各类石油污染物和钻井混合废弃物样品中分离出30余种微生物菌株,通过分离筛选、培养驯化和激光诱变等技术手段,选育出5种在钻井混合废弃物中能够迅速生长的优良菌株,并对此5株菌株通过形态学、生理生化、分子鉴定等手段进行了分类鉴定（鉴定到属）。针对陕北地区油气田钻井混合废弃物的主要污染物成分,根据5种菌株各自的生理生化特征和作用特点,通过科学复配的方法开发出微生物复合固体菌剂。菌剂中各种微生物能够利用含不同有害成分的油气田钻井混合废弃物作为唯一营养源迅速繁殖、互利生长。将微生物复合固体菌剂按比例接入钻井混合废弃物中,在＞10℃的温度条件下,钻井混合废弃物中微生物能够迅速增殖至10¹⁰个/g以上,各类菌在钻井混合废弃物中互利生长,通过复合菌群的生长代谢作用可使钻井混合废弃物转化形成适宜各类生物生长的良好微生态环境。钻井混合废弃物经微生物复合固体菌剂作用后全方位高效降解转化了各类污染物成分,大大降低了钻井废弃物对自然生态环境的危害。经处理后钻井混合废弃物的破胶、分层、脱水效果极为显著,pH值可由强碱性恢复至中性,表面出现固化,深度龟裂,钻井混合废弃物中石油烃类物质降解率可以达到95%以上,六价铬的转化率可以达到99%,pH值降至6.5-7.5,活菌数达10¹⁰个/g以上,水分含量降至40-60%,有机质含量与周边土壤相比增加300%以上,达到脱毒、脱胶、固液分离、降低酸碱度的目的。通过58个不同地域、不同环境、不同类型油气田井场泥浆池原位修复示范应用实验,证明了在陕北自然条件下微生物复合固体菌剂可以对钻井混合废弃物进行有效的原位生物修复。在接种量0.3%-0.8%、温度＞10℃的条件下,复合菌剂中微生物能够以钻井混合废弃物作为唯一营养源迅速生长繁殖,有效地降解、利用、转化废弃物中各类有害成分。钻井混合废弃物的破胶、分层、脱水极为明显,pH值可由强碱性恢复至中性,使钻井混合废弃物迅速转化形成适宜各类生物生长的良好微生态环境,大大降低和消除钻井混合废弃物对自然生态环境的危害。实验所处理的58个油、气井场的泥浆池30-60天后完全达到生物修复处理效果,均通过当地环保部门和油田相关部门按国家环保标准和油田工程管理规定的现场达标验收。更多还原

【Abstract】 The intermixture of drilling waste,which is mainly composed of waste drilling-mud, waste drilling water,drainage,cuttings and fracturing flow-back fluid,is the blending contaminants yielded during the exploit and exploration procedure of petroleum and natural gas.It was classified as a sort of toxic solid waste which contains large mounts of pollutants such as petroleum and heavy metal ion.The biggest environment risks generated during the exploration of petroleum and natural gas were largely due to it.Directly towards the contaminants within the intermixture of drilling waste,the present study was undertaken to screening a certain group of microbes with ability of contaminants degradation in high efficiency.Through the metabolism of microbe groups,contaminants within the intermixture of drilling waste could be degraded effectively and the environment risk generated during the exploration of petroleum and natural gas can be vanished.30 isolates of microbe strains were isolated from 23 samples of different sources by Plate Dilution method.5 isolates with high ability of contaminants degradation were screening from these 30 isolates.Through the traditional bacterial systemic identification method and the analysis of 16S rDNA &18S rDNA sequence,the 5 strains were respectively identified as Bacillus、Acinetobacter、Rhodococcus、Pseudomonas and Glomus.According to the characteristics of strains,the compound solid inoculant which contains all 5 strains was developed to obtain higher degradation efficiency.The experiment result showed that the total counts of microbial reached 10¹⁰/g within a short time after the inoculation when the environmental temperature＞10℃.Strains could make the contaminants within the intermixture as the only nutrients source to get themselves grew As well as each strains obtained a better grow activity due to the corporations between the strains.Through the metabolism of microbe groups from the compound solid inoculants, contaminants within the intermixture of drilling waste obtained a great degradation.After 30-60 days degradation,the total content of petroleum hydrocarbons in the intermixture were reduced at the level of 95%;the content of Cr⁶⁺ was reduced by 99%;pH were changed from＞10 to 6.5-7.5;the total counts of microbial reached 10¹⁰/g;the content of water changed to 40%-60%;even the content of organic matter could increase 300%according to these in the soil.The contents of main contaminants in the intermixture of drilling waste were reduced at a great level;the characteristics of intermixture were changed to make new possibility for planting.The aim to minimize the risk of intermixture to the environment was perfectly met.After experimental work in lab,On Site Microbial Ecological Recovery experiment was carded out in YuLin and WuQi at the northern of Shaanxi province.After 30-60 days,the all 58 mud pit which ecological recovery experiments carded out were got through the examination from Environmental Protection agency from local government.The recovery results indicated that the microbial method could effectively remediate the intermixture of drilling waste under the natural environmental condition in the northern of Shaanxi province.更多还原