【摘要】：銀額盆地位于內(nèi)蒙古西部,自古生代形成之后經(jīng)歷了多期次構(gòu)造改造。燕山期構(gòu)造運動使盆地經(jīng)歷了陸內(nèi)盆山構(gòu)造演化,并在白堊紀孕育了查干凹陷、居延海凹陷等一系列的生油凹陷,這些生油凹陷的構(gòu)造演化過程還有待進一步研究。本文通過對銀額盆地西北部希熱哈達地區(qū)(居延海凹陷)的5口鉆井開展磷灰石裂變徑跡研究,揭示了研究區(qū)中生代構(gòu)造演化史。8個樣品的中心年齡為111±8~140±8Ma,徑跡長度在12.1±1.9~12.8±2.2μm之間,各樣品徑跡長度分布具有單峰、負偏的特征。反映了在晚侏羅世—早白堊世時期,受燕山Ⅲ幕構(gòu)造運動影響,研究區(qū)遭受抬升、剝蝕的構(gòu)造事件。該時期是研究區(qū)主要抬升期,根據(jù)研究區(qū)部分鉆井樣品的鏡質(zhì)體反射率恢復(fù)中下侏羅統(tǒng)剝蝕厚度在1069.06~2503.73m之間,證明該時期抬升強烈,油氣系統(tǒng)遭受破壞。同時,利用Hefty軟件對8個樣品開展的熱史模擬較為一致地反應(yīng)研究區(qū)在晚侏羅世之前達到最大埋深,之后在140~111Ma之間經(jīng)歷了短暫的快速抬升,進入磷灰石退火帶溫度范圍(120℃左右)。此后較長時間內(nèi)溫度保持極為緩慢的降低,直至60~40Ma退出退火溫度上限即生油門限溫度,并持續(xù)至今,期間并無強烈的構(gòu)造抬升。結(jié)合與銀額盆地中部雅干地區(qū)和東部尚丹凹陷所開展工作(磷灰石裂變徑跡記錄年齡為90~113Ma,129~159Ma),證明銀額盆地中生代時期存在差異隆升,不同構(gòu)造位置受不同期次構(gòu)造運動的影響也存在差異,為銀額盆地構(gòu)造演化研究提供了依據(jù)。
[Abstract]:The Yinzao basin is located in the west of Inner Mongolia and has undergone multiple structural transformations since the Paleozoic formation. During the Yanshanian tectonic movement, the basin underwent the evolution of intracontinental basin-orogenic structure, and a series of oil-generating sag, such as Chagan sag and Juyanhai sag, were conceived in the Cretaceous. The structural evolution process of these oil-generating sag needs to be further studied. Based on the study of apatite fission track in 5 wells in Xije-hada area (Juyanhai Sag) in northwestern Yinye Basin, the authors reveal the Mesozoic tectonic evolution history of the studied area. The central age of 8 samples is 111 鹵8140 鹵8 Ma. The length of track is between 12.1 鹵1.9 渭 m and 12.8 鹵2.2 渭 m, and the length distribution of each sample has the characteristics of single peak and negative deviation. It reflects the tectonic events of uplift and denudation in the study area during the late Jurassic-early Cretaceous period affected by the Yanshanian III act tectonic movement. This period is the main uplift period in the study area. According to the vitrinite reflectance of some drilling samples in the study area, the denudation thickness of the Middle and Lower Jurassic is between 1069.06 and 2503.73 m, which proves that the uplift is strong and the oil and gas system is destroyed in this period. At the same time, the thermal history of eight samples was simulated by Hefty software. The study area reached the maximum burial depth before the late Jurassic, and then experienced a short period of rapid uplift between 140~111Ma. Enter the apatite annealing zone temperature range (about 120 鈩，

本文編號：2315083