原油裂解气与干酪根裂解气差异实验研究

Laboratory studies of differences between oil-derived and kerogen maturation gases

郭利果 肖贤明 田辉

Guo Liguo Xiao Xianming Tian Hui

南京大学 地球科学与工程学院 地球科学系, 南京 210093 2. 中国石油化工股份有限公司 石油勘探开发研究院 无锡石油地质研究所, 江苏 无锡 214151 3. 中国科学院 广州地球化学研究所 有机地球化学国家重点实验室, 广州 510640

Department of Geosciences, Geosciences and Engineering Institute, Nanjing University, Nanjing, Jiangsu 210093, China 2. Wuxi Research Institute of Petroleum Geology, SINOPEC, Wuxi, Jiangsu 214151, China 3. State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, Guangdong 510640, China

对取自渤海湾盆地东营凹陷的一块湖相未成熟I型烃源岩,应用分步裂解生烃、抽提与族组分分离、配分的实验方法,获得了同一母质来源的合成油(S-油)和似干酪根(P-干酪根)样品.应用黄金管限定体系,对2个样品进行生烃热模拟实验,测定2类热解气体的成分与碳同位素值.研究结果表明,2类气体性质明显不同.与P-干酪根相比,S-油裂解气具有以下特点:在裂解早期阶段,C2-C5重烃含量高,湿度大;C1-C3气体碳同位素轻,两者差值最大可达10‰(C1),14‰(C2)和9‰(C3);(δ13C2-δ13C3)值较大,受成熟度影响大.在实验条件下获得的(δ13C2-δ13C3)-δ13C1和(δ13C2-δ13 C3)-ln(C2/C3)图解能有效区分这2类裂解气.本研究成果为地质条件下原油裂解气与干酪根裂解气的判别提供了理论指南.

An immature type-I mudstone collected from the third section of the Tertiary Shahejie Formation (Es33) in the Dongying Sag of the Bohai Bay Basin was studied with laboratory experiments.Products were extracted,fractionated into chemical groups,and re-mixed to obtain synthetic oil (s-oil) with a group composition similar to reservoir oil and a pseudo-kerogen (p-kerogen) composed of 83% kerogen and 17% residual soluble organic matter.The two samples were pyrolyzed in sealed gold tubes under constant pressure and non-isothermal heating conditions and the generated gases were analyzed.The two gases are quite different in their chemical and isotopic composition.Compared with the gas derived from p-kerogen,the s-oil-derived gas is rich in C2-C5 hydrocarbons during the early cracking stages and C1-C3 hydrocarbons are depleted in δ13C throughout the cracking stages.The carbon isotopic ratio differences between the two gases can reach 10‰ (δ13 C1),14‰ (δ13 C2),and 9‰ (δ13 C3).The δ13C2-δ13C3 value of the s-oil gas is much more sensitive to thermal stress than that of the p-kerogen gas and the plots of (δ13C2-δ13C3) versus δ13 C1 and (δ13C2-δ13C3) versus ln(C2/C3) are effective in identifying the two gas types.These results provide a guide to differentiate gases derived from oil cracking from those derived from kerogen maturation.

国家杰出青年基金项目(40625011);中国科学院知识创新项目(KZCX2-YW-114)资助

https://doi.org/10.11781/sysydz201104428