安岳气田下寒武统海相烃源岩总有机碳 含量测井预测

Log Prediction of Total Organic Carbon Content in the Lower Cambrian Marine Source Rocks of Anyue Gas Field

安岳震旦系-寒武系特大型整装气田下寒武统海相烃源岩具有热演化程度高、有机碳含量丰富、生烃潜力巨大等特点,是震旦系-下古生界油气成藏的重要物质基础。目前尚未建立下寒武统烃源岩有机碳测井评价方法,优质烃源岩的分布情况不确定。根据研究区测井、岩心分析、地化等资料,通过分析岩心总有机碳含量与对应测井响应参数之间的关系,建立总有机碳含量的预测模型。通过研究区30余口单井烃源岩有机碳含量计算,完成研究区优质烃源岩分布情况预测。研究认为,德阳安岳裂陷槽内发育麦地坪组与笻竹寺组2套泥质烃源岩,烃源岩有机碳含量大于2.0%的优质烃源岩的累计厚度达到200 m以上,是四川盆地震旦系-下古生界主要生烃中心;磨溪构造北斜坡存在一个下寒武统的烃源灶,其内优质烃源岩的厚度超过了20 m,是研究区下一步的勘探方向。

The Lower Cambrian marine source rocks in Sinian-Cambrian super large gas field in Anyue gas field have the characteristics of high thermal evolution,abundant organic carbon content and huge hydrocarbon generation potential,which are the important material basis for hydrocarbon accumulation.However,the organic carbon log evaluation method for Lower Cambrian source rocks has not been established yet,and the horizon distribution of high-quality source rocks is uncertain.According to the log,core analysis,geochemistry and other data in the study area,combined with geophysical log theory,this paper established a prediction model of total organic carbon content by analyzing the relationship between the total organic carbon content of the core and the corresponding log response parameters,and the test results have high reliability.Through TOC content calculation of over 30 wells in the study area,distribution prediction of high-quality hydrocarbon source rocks in the study area was completed.The study shows that two sets of argillaceous source rocks,Maidiping formation and Qiongzhusi formation,are developed in Deyang-Anyue rift trough.The cumulative thickness of TOC content more than 2.0%is over 200 meters,which is the main hydrocarbon generation center of Sinian-Lower Paleozoic in Sichuan Basin.In addition,it is found that there is a Lower Cambrian hydrocarbon source kitchen in the northern slope of Moxi structure.The thickness of the high quality source rocks in the kitchen is over 20 meters,which is a favorable exploration direction for the next step in the study area.