雅布赖盆地萨尔台凹陷古地温场与油气成藏期次  

The Paleogeothermal Field and Hydrocarbon Accumulation Period in Sartai Depression,Yabrai Basin

作　　者：田涛[1] 任战利[1] 吴晓青[1] 马国福[2] 张睿胜 杨智明[2] 郭科[1] 

机构地区：[1]西北大学大陆动力学国家重点实验室,西安710069 [2]中石油玉门油田分公司,甘肃酒泉735000

出　　处：《沉积学报》2015年第4期836-844,共9页Acta Sedimentologica Sinica

基　　金：国家自然科学基金(批准号:41372128)资助

摘　　要：为了探明雅布赖盆地萨尔台凹陷中侏罗统烃源岩经历的古地温环境及其与油气成藏的关系，利用镜质体反射率（Ro）、磷灰石裂变径迹（AFT）、流体包裹体等古温标揭示古地温大小，并建立烃源岩热演化史模型，在此基础上结合流体包裹体均一温度进行油气成藏期次判定。研究区现今为低温传导型地温场，地温梯度为2．76℃／100m。不同次级构造单元古地温场特征不同：盐场次凹、小湖子次凹为传导型古地温场，古地温梯度为2．8-3．4℃／100m，古地温约81．2℃-128．1℃；黑沙低凸起带受凸起聚热或热异常作用的影响，古地温梯度明显高于沉积凹陷区域，达到4．0-4．8℃／100m，古地温约103．2℃～140．2℃。中侏罗统古地温高于现今地层温度，有机质成熟演化主要受古地温场的控制。热史模拟和油气成藏期次分析表明，萨尔台凹陷不同次级构造单元油气充注过程稍有差异，但对整个萨尔台凹陷中侏罗统储层来讲主要存在两期油气充注过程，分别发生在晚侏罗世早期（145．0～152．0Ma）和早白垩世（100．0～134．0Ma），与达到古地温峰值的时间大致相当，体现出古地温场演化在油气成藏过程中的重要性。In order to find out the relations between paleogeothermal field and hydrocarbon accumulation, vitrinite re- flectance （Ro）, apatite fission track （AFF） and homogenization temperature of fluid inclusions were discussed for re- vealing the paleotemperature. Hydrocarbon accumulation period was judged by the results of homogenization tempera- ture of fluid inclusions based on the thermal history simulation. In the study area, the temperature of current-geother- mal field is low and conductive with the geothermal gradient of 2.76 ℃/100m. The paleogeothermal field of each sec- ondary tectonic unit in Sartai depression was different： The paleogeothermal field of Yanchang and Xiaohuzi sub-sag was conductive with the paleo-geothermal gradient of 2.8- 3.4 ℃/100m and the paleotemperature was 81.2℃ 128.1 ℃ ; The paleotemperature and paleo-geothermal gradient in Heisha Low Uplift were 103.2℃ -140.2℃ and 4.2 4.8 ℃/100m, much higher than that in sedimentary depression because of the thermal polymerization and thermal a- nomaly of the low uplift. The Evolution of maturity was mainly controlled by paleogeothermal field , because the paleo- temperature of Middle Jurassic was higher than the present. The analysis of thermal history simulation and hydrocarbon accumulation period show that the hydrocarbon filling process of the three second tectonic units are different. Howev- er, for the whole Middle Jurassic reservoir in Sartai depression, there were two times of hydrocarbon filling process happened at early stage of Late Jurassic （ 145.0- 152.0 Ma） and Early Cretaceous（ 100.0- 134.0 Ma） about the same time of peak paleogeothermal which reflected the importance of geothermal evolution in the process of hydrocarbon ac- cumulation.

关 键 词：雅布赖盆地 萨尔台凹陷 中侏罗统 古地温 油气成藏期次 

分 类 号：P618.13[天文地球—矿床学]