准噶尔盆地阜康凹陷东斜坡侏罗系头屯河组油气成藏期次

准噶尔盆地阜东斜坡侏罗系头屯河组油气同产。在前人研究的基础上，利用原油碳同位素、姥植比以及生物标志物资料，对阜东斜坡侏罗系头屯河组原油成因进行分析；并结合储层流体包裹体特征，探讨了其油气成藏期次。研究表明：阜东斜坡侏罗系头屯河组原油碳同位素值介于 -27.59‰~-29.97‰之间，姥植比较大，呈现出混源的特征；原油饱和烃色谱完整但质谱图上可见完整的25?降藿烷系列，说明阜东斜坡侏罗系头屯河组原油至少存在2期油气充注。储层中存在2期油气包裹体：一期赋存于石英颗粒微裂隙中，发黄绿色和黄色荧光；另一期赋存于切穿石英颗粒的微裂隙中，发蓝色荧光；结合埋藏—地热史分析认为，阜东斜坡侏罗系头屯河组存在2期油气充注，第一期油气来自二叠系腐泥型源岩，并在晚白垩世遭到破坏，第二期油气为侏罗系腐殖型源岩和二叠系腐泥型源岩产物的混合。研究区侏罗系头屯河组为充注—局部破坏—二次充注的成藏过程。

Study on hydrocarbon accumulation stage of Jurassic Toutunhe Formation in Fudong Slope,Junggar Basin

Based on previous studies, the carbon isotope, Pr/Ph ratio and biomarker characteristics are used to investigate the genesis of the Jurassic Toutunhe Formation in the Fudong Slope of Junggar Basin, and in combination with the characteristics of reservoir fluid inclusions, the hydrocarbon accumulation period is discussed. The results show that the carbon isotope of crude oil ranges from -27.59‰ to -29.97‰ with high Pr/Ph ratio, showing the character of mixed. The saturated hydrocarbon chromatography of the crude oil is complete but 25-norhopane can be detected which indicates that there are at least two periods of hydrocarbon charging. The hydrocarbon inclusions are located in micro-fractures within quartz grains with yellow fluorescence and micro-fractures through quartz grains with blue fluorescence. There are two uncontinuous major hydrocarbon accumulation stages. Oil and gas of the first stage is from Permian sapropelic source rocks and was destroyed in the Late Cretaceous. The second stage of oil and gas is a mixture of products from Jurassic humic source rocks and Permian sapropelic source rocks. The oil and gas accumulation process in the study area is characterized by “charging-damage-recharging”.