CAJ | 학술논문

对川西坳陷孝泉—新场—合兴场地区须二段天然气组成及碳同位素的分析表明,须二段天然气为煤型气和油裂解气的混合成因气,其气源有3种：①马鞍塘组—小塘子组烃源岩,腐殖-腐泥混合型有机质生油生气,而后油在高温下裂解成气;②须二段内部烃源岩,以生气为主,自生自储;③须三段烃源岩对须二段天然气聚集也有贡献,但贡献极小。在对须二段气藏烃源岩生排烃高峰期天然气充注史与岩石致密演化之间的动态关系进行分析判定,认为须二段气藏属于典型的＂后成型＂致密气藏,其成藏过程符合＂早聚、中封、晚活化＂的成藏模式。
대천서요함효천—신장—합흥장지구수이단천연기조성급탄동위소적분석표명,수이단천연기위매형기화유렬해기적혼합성인기,기기원유3충：①마안당조—소당자조경원암,부식-부니혼합형유궤질생유생기,이후유재고온하렬해성기;②수이단내부경원암,이생기위주,자생자저;③수삼단경원암대수이단천연기취집야유공헌,단공헌겁소。재대수이단기장경원암생배경고봉기천연기충주사여암석치밀연화지간적동태관계진행분석판정,인위수이단기장속우전형적＂후성형＂치밀기장,기성장과정부합＂조취、중봉、만활화＂적성장모식。
The analysis of natural gas composition and carbon isotope of the second member of Upper Triassic Xujiahe Formation in Xiaoquan-Xinchang-Hexingchang area of West Sichuan depression indicates that the natural gas is hybrid origin consisting of coaliferous gas and oil-cracked gas.It has three sources：①source rock of Maantang and Xiaotangzi Formation,humic-sapropelic organic material generated oil and gas and then the oil cracked into gas under high temperature;②source rock within the second member of Xujiahe Formation,gas-generated mainly,self-generating and self-reserving;③source rock within the third member of Xujiahe Formation,which did few contributions to the gas accumulation of the second member of Xujiahe Formation.By analyzing the dynamic relationship between gas charging history and the rock-tightening evolution,the gas reservoir of the second member of Xujiahe Formation is judged as a typical ＂subsequent tight sand gas＂ reservoir,whose accumulation process conformed to the specific mode of ＂early accumulation-seal up-late activation＂.