腐泥型干酪根热降解成气潜力及裂解气判识的实验研究  

Experimental research on the potential of sapropelic kerogen cracking gas and discrimination of oil cracking gas

作　　者：谢增业[1,2] 李志生[1,2] 魏国齐[1,2] 李剑[1,2] 王东良[1,2] 王志宏[1,2] 董才源[1,2] 

机构地区：[1]中国石油勘探开发研究院廊坊分院,河北廊坊065007 [2]中国石油天然气集团公司天然气成藏与开发重点实验室,河北廊坊065007

出　　处：《天然气地球科学》2016年第6期1057-1066,共10页Natural Gas Geoscience

基　　金：国家科技重大专项(编号:2011ZX05007-002);中国石油股份公司科技项目(编号:2014B-0607)联合资助

摘　　要：腐泥型有机质在成烃演化过程中以先生成原油再裂解成气已有共识,但有多大的比例是由干酪根直接降解生成以及如何鉴别尚存异议。选取华北地区下马岭组低成熟腐泥型页岩,采用高温高压黄金管体系及常规高压釜热模拟实验装置,对同源于该页岩的原始干酪根、残余干酪根和原油开展了生气模拟实验。结果表明：（1）腐泥型有机质生油高峰期后,干酪根直接降解成气量占总生气量的20%左右;原油裂解主成气期为422566℃（RO=1.3%2.5%）,生气量占裂解气总量的85.5%。（2）干酪根降解气和原油裂解气Ln（C1/C2）值与Ln（C2/C3）值均随演化程度增高而增大,但受原油和干酪根结构差异、裂解生气速率及所需活化能大小的影响,过成熟阶段,干酪根降解气Ln（C2/C3）值逐渐增大,原油裂解气Ln（C2/C3）值基本稳定,且低升温速率的Ln（C1/C2）值比高升温速率的值大。（3）新建考虑演化阶段的裂解气判识图版,认为四川盆地震旦系—寒武系天然气主要为原油裂解气。研究成果进一步明确了腐泥型烃源岩发育区,高演化阶段以寻找原油裂解气为主要目标,而非烃源岩晚期干酪根降解气,并可为有机质全过程生烃演化轨迹曲线的确定提供重要依据。It is the consensus that sapropelic matter generated oil at first and then the oil cracked into gas in the process of hydrocarbon-generation evolution,however,there is still dispute that how much gas is generated by kerogen directly and how to identify it.The experimental samples are low mature sapropelic shale in Xiamaling Formation in North China,the experimental devices are high temperature-pressure gold tube system and normal autoclave thermal simulation,gas generation simulation experiments of original kerogen,residual kerogen and oil from the same shale are developed.It concluded that：（1）the gas generated from kerogen directly accounts for about 20%after the oil generation peak period,The main gas generating stage is from 422-566℃（RO=1.3%-2.5%）,and the amount takes up 85.5%.（2）the value of Ln（C1/C2）and Ln（C2/C3）increases with the growth of evolution degree for both kerogencracking gas and oil cracking gas.However,at over mature period,the value of Ln（C2/C3）increases for the kerogencracking gas while the value for oil cracking gas keeps stable,and the value of ln（C1/C2）at low heating rateislarger than that at high heating rate.（3）the new oil cracking gas discrimination chart is established consideringevolution degree.The gas from Sinianand Cambrian in Sichuan Basin is oil cracking gas from the above understanding.The research resultsreveal that not kerogen cracking gas but oil cracking gas is the main target at high evolution degree where sapropelic matter developed,and these can provide important evidence for the determination of whole process hydrocarbon-generation evolutionlocus curve of organic matter.

关 键 词：腐泥型有机质 干酪根降解气 原油裂解气 成因判识 震旦系—寒武系 高石梯—磨溪 四川盆地 

分 类 号：TE122.113[石油与天然气工程—油气勘探]