Study on the Genesis of H2S-Bearing Natural Gas in Carbonate Reservoirs

Abstract

Abstract: Isothermal simulation experiments on natural gas-solid calcium sulfate system have been carried out under high temperature and high pressure, and possible reaction pathways and thermodynamic characteristics of thermochemical sulfate reduction (TSR) have been discussed. The results show that hydrogen sulfide, carbon dioxide, calcium carbonate, water and carbon are the main products in the TSR system. With increasing TSR, the total hydrocarbon amount in natural gas decline, and the gas dryness and gas souring index increase. The general reaction expression for TSR involving natural gas and a thermodynamic analysis of TSR system are given. Longchain hydrocarbons take priority of reaction with solid calcium sulfate over short-chain hydrocarbons. Feixianguan formation oolitic shoal high H2S natural gas pool in northeastern Sichuan basin is taken as an example for geologic case studies of TSR system. It is found that the results from simulation experiments basically coincide with the geologic case studies.

Key words: natural gas, solid calcium sulfate, thermal simulation experiment, TSR, H2S, geologic exemplification, case study

CLC Number:

TE112.221

DING Kang-le, LI Shu-yuan, YUE Chang-tao, ZHONG Ning-ning. Study on the Genesis of H2S-Bearing Natural Gas in Carbonate Reservoirs[J]. Xinjiang Petroleum Geology, 2008, 29(4): 535-538.

References

[1] 戴金星, 陈践发, 钟宁宁, 等. 中国大气田及其气源[M] .北京: 科学出版社, 2003: 9-30.
[2] 戴金星, 石昕, 卫延召. 无机成因油气论和无机成因的气田(藏) 概略[J] . 石油学报, 2001, 22(6) : 5-10.
[3] 朱光有, 戴金星, 张水昌, 等. 含硫化氢天然气的形成机制及分布规律研究[J] . 天然气地球科学, 2004, 15(2) :166-170.
[4] Worden R H, Smalley P C, Oxtoby N H. Gas souring by thermochemical sulfate reduction at 140℃[J] . American Association of Petroleum Geologists Bulletin, 1995, 79(6) : 854-863.
[5] Riciputi L R, Cole D R, Machel H G. Sulfide formation in reservoir carbonates of the Devonian Nisu formation, Alberta, Canada[J] . Geochimica Cosmochimica Acta, 1996, 60(2) :325-336.
[6] Machel H G, Krouse H R, Sassen R. Products and distinguishing criteria of bacterial and thermochemical sulfate reduction[J] . Applied Geochemistry, 1995, 10(4) : 373-389.
[7] Worden R H, Smalley P C. H2S-producing reactions in deep carbonate gas reservoirs: Khuff formation, Abu Dhabi[J] .Chemistry Geology, 1996, 133(1-4) : 157-171.
[8] Machel H G. Bacterial and thermochemical sulfate reduction in diagenetic settings: old and newinsights[J] . Sedimentary Geology, 2001, 140(1-2) : 143-175.
[9] Cai C F,Worden R H, Bottrell S H, et al. Thermochemical sulfate reduction and the generation of hydrogen sulphide and thiols(mercaptans) in Triassic carbonate reservoirs from the Sichuan basin, China[J] . Chemical Geology, 2003, 202(1) : 39-57.
[10] 朱光有, 张水昌, 梁英波, 等. 硫酸盐热化学还原反应对烃类的蚀变作用[J] . 石油学报, 2005, 26(5) : 48-52.
[11] 张奎华. 川东北地区三叠系飞仙关组高硫化氢气藏成因探讨[J] . 油气地质与采收率, 2006, 13(2) : 47-49.
[12] 闻辂, 梁婉雪, 章正刚. 矿物红外光谱学[M] . 重庆: 重庆大学出版社, 1989: 55-65.
[13] 傅家谟, 盛国英, 刘德汉. 煤成烃地球化学[M] . 北京: 科学出版社, 1990: 151-172.
[14] 邓景发, 范康年. 物理化学[M] . 北京: 高等教育出版社,1993: 801-802.
[15] 朱光有, 张水昌, 梁英波. 川东北飞仙关组H2S 的分布与古环境的关系[J] . 石油勘探与开发, 2005, 32(4) : 65-69.
[16] 谢增业, 田世澄, 李剑, 等. 川东北飞仙关组鲕滩天然气地球化学特征与成因[J] . 地球化学, 2004, 33(6) : 567-573.