鄂尔多斯盆地延长组长7致密储层流体包裹体特征与成藏期次

Hydrocarbon accumulation dating by fluid inclusion characteristics in Chang7 tight sandstone reservoirs of Yanchang Formation in Ordos Basin

时保宏 张艳 张雷 杨亚娟 李慧

Shi Baohong Zhang Yan Zhang Lei Yang Yajuan Li Hui

西安石油大学地球科学与工程学院, 西安, 710065 2. 中国石油天然气股份有限公司长庆油田分公司勘探开发研究院, 西安, 710021 3. 中国石油天然气股份有限公司长庆油田分公司第七采油厂, 西安, 710018

School of Earth Science and Engineering, Xi'an Shiyou University, Xi'an, Shaanxi 710065, China 2. Institute of Exploration and Development, Changqing Oil and Gas Branch Company, PetroChina, Xi'an, Shaanxi 710021, China 3. The 7th Oil Plant, Changqing Oil and Gas Branch Company, PetroChina, Xi'an, Shaanxi 710018, China

鄂尔多斯盆地延长组长7储层流体包裹体类型丰富,包括盐水包裹体、含烃盐水包裹体、液烃包裹体、气液烃包裹体和气烃包裹体。根据油气包裹体宿主矿物成岩的形成时间序列和均一温度分析认为,长7储层主要有2期包裹体。第一期主要赋存于石英颗粒次生加大边内侧及未切及加大边的裂隙中,与其共生的盐水包裹体均一温度峰值为120～140℃;第二期包裹体均沿切穿石英(或长石颗粒)的晚期微裂隙成线/带状分布,与其共生的盐水包裹体均一温度峰值为90～110℃。结合盆地埋藏史和热史分析认为,长7致密油藏主要经历了2次流体充注,主成藏期为早白垩世晚期,即在早白垩世末盆地开始大范围抬升以前油藏就已形成。

There are various fluid inclusions in the Chang 7 reservoir of the Yanchang Formation in the Ordos Basin.According to the diagenetic stages and homogenization temperatures of host minerals for fluid inclusions,two different phases of hydrocarbon inclusions have been identified.The hydrocarbon inclusions of the first phase locate in the interiors and fissures of quartz overgrowth area and the homogenization temperature of brine inclusions is from 120℃ to 140℃.The hydrocarbon inclusions of the second phase locate in the late fissures which cut across quartz and(or)feldspars and the homogenization temperature of brine inclusions is mainly from 90℃ to 110℃.Combined with the thermal and burial histories of the Chang 7 Formation,the tight reservoirs has experienced two stages of fluid filling.The main accumulation took place during the late period of Early Cretaceous.

陕西省教育厅项目(11JK0735)资助

https://doi.org/10.11781/sysydz201206599