SIMULATION EXPERIMENT OF BIOGENIC GAS FROM SOURCE ROCK AND BIODEGRADATION OF CRUDE OIL IN THE JIYANG DEPRESSION, THE BOHAI BAY BASIN
-
摘要: 通过细菌检测实验,系统分析了渤海湾盆地济阳坳陷生物气源岩中细菌的赋存状况。实验表明,济阳坳陷浅层气源岩中产甲烷菌较为丰富,在2522m深处还有产甲烷菌存在,并且产甲烷菌赋存的源岩与源岩时代无相关关系,只要有适合生物气形成的环境条件,生化作用就可能发生。通过气源岩和原油在不同温度下的生物模拟实验,分析了济阳坳陷生物模拟气产率、组分及碳氢同位素特征,结果表明,无论是气源岩还是原油厌氧降解生成的生物气,都只生成甲烷和二氧化碳;45℃和65℃是生物气生成的高峰期,生物气产率分布范围为每吨TOC产气20~160m3和每吨原油产气10~15m3;生物模拟实验产物的碳同位素值随温度变化差异明显,变化范围为-80.2‰~-41.5‰;生成的二氧化碳的碳同位素值变化与甲烷碳同位素值变化规律相反;生物模拟气中氢同位素的值则比实际生物气的氢同位素值轻,模拟气中氢同位素值主要分布在-300‰~-350‰,而实际生物气的氢同位素值则分布于-240‰~-270‰。Abstract: Detection of the bacteria in the source rocks from different types of formation,lithology and depth in the Jiyang Depression was carried out in this paper.The result shows that the methane-forming bacteria exist in mudstone and sandstone in Es3,Es1 and Ed formations with depth being from 1 297 to 2 522 meters,indicating that the existence of methane-forming bacteria depends on the survival environment of the bacteria and is independent of rock's formation and lithology.The characteristics of the biogenic gases from source rocks and biodegradation of crude oil are similar in simulation experiment.The products of simulation experiment are mathane and carbon dioxide.Temperatures at the biogenic gas generating peak are 45℃ and 65℃.The yields of biogenic gases generated by a ton of TOC and a ton of crude oil are 20-160 m3 and 10-15 m3 respectively.Carbon isotope compositions of methane which range between -80.2‰ and -41.5‰ become lighter with simulation temperature going up,while carbon isotope compositions of carbon dioxide become heavier.Hydrogen isotope compositions of biogenic gas in simulation which mainly range between -300‰ and -350‰ are lighter than those in actual formation like the Luliang Basin in Yunnan Province which mainly range between -240‰ and -270‰.
-
[1] 降栓奇,杨桂茹,淡伟宁等.廊固凹陷浅层天然气成因类型及机制[J].天然气工业,2001,21(3):5~8 [2] 杨显成,耿春燕,郭谨等.阳信凹陷油气分布规律及勘探方向[J].油气地质与采收率,2003,10(6):24~27 [3] 史占桢.渤海湾盆地及其外围的生物气研究[J].天然气工业,2002,22(9):11~16 [4] 赵一章,邓宇,尹小波等.产甲烷细菌及其研究方法[M].成都:成都科技大学出版社,1997.22~23 [5] 戴金星.戴金星天然气地质和地球化学论文集(卷1)[M].北京:石油工业出版社,1998.223~230 [6] 钱贻伯,连莉文,陈文正等.生物气形成过程中CH4碳同位素变化规律的研究[J].石油学报,1998,19(1):29~33 [7] 张淮,周荔青.陆良盆地生物气藏形成分布规律[J].石油实验地质,2005,27(6):588~593 -
计量
- 文章访问数: 639
- HTML全文浏览量: 39
- PDF下载量: 304
- 被引次数: 0