(U-Th)/He技术约束下库车盆地北缘构造热演化——以吐孜2井为例

库车前陆盆地蕴藏着丰富的油气资源，然而盆地中新生代的构造热演化史一直缺乏有效的研究，制约了油气的勘探.本文测试了吐孜2井磷灰石、锆石（U-Th）/He年龄数据，建立了He年龄随现今温度/深度变化的关系，确定该区磷灰石（U-Th）/He体系封闭温度为89℃.综合利用（U-Th）/He及镜质体反射率（R_o）数据模拟恢复了库车盆地吐孜2井中新生代热演化史，结果表明库车盆地吐孜洛克背斜形成起始时间约为5 Ma，新生代抬升剥蚀量平均约为670 m，平均抬升剥蚀速率为0.133 mm/a.根据新生代吐孜洛克背斜的构造演化分析确定了气源断裂活动及圈闭形成的时期，揭示了吐孜洛克背斜天然气成藏时间为5 Ma以后，且烃源岩生排烃、断裂活动及圈闭形成的时间具有良好的匹配关系，这是吐孜洛克油气田形成的关键因素之一.本文应用（U-Th）/He技术研究沉积盆地构造热演化史，对库车盆地油气勘探具有重要的意义.

(U-Th)/He thermochronometry constraints on the Mesozoic-Cenozoic tectono-thermal evolution of Kuqa basin：A case study of well TZ2

The oil and gas resources in Kuqa foreland basin are rich,however, there is a lack of effective researches of the tectonic thermal history in the Mesozoic and Cenozoic period, which is important for oil and gas exploration. Based on the tested apatite and zircon He ages data from drilling well samples,the He closure temperature of borehole apatites from Kuqa basin is determined (about 89℃) by analyzing the relationship between apatite ages of (U-Th)/He and depth/temperature in profile. Mesozoic-Cenozoic thermal history of the well TZ2 will has been modeled by using the He ages and vitrinite reflectance (R_o) data. The modeling result shows that the forming time of Tuziluoke anticline started at 5 Ma, and it uplifted and eroded about 670 m in Cenozoic period with the average erosion rate of 0.133 mm/a. According to structural evolution analysis of Tuziluoke anticline, the time of gas-migrating fault activity and trap formation was determined, which demonstrated the time of gas accumulation in the Tuziluoke anticline was 5 Ma. The consistency of the times of the hydrocarbon generation and expulsion, fault activity and trap formation was key factor for gas accumulation in Tuziluoke anticline. Therefore, application of the (U-Th)/He technology to the tectono-thermal evolution of sedimentary basin has the important significance for oil and gas exploration in Kuqa basin.