塔里木盆地库鲁克塔格奥陶系牙形石色变指标与有机质成熟度的关系  

THE RELATIONSHIP BETWEEN CONODONT COLOR ALTERATION INDEX AND ORGANIC MATTER MATURITY OF THE ORDOVICIAN HYDROCARBON SOURCE ROCKS IN KULUKETAGE DISTRICT, TARIM BASIN

作　　者：李金龙[1] 王璞珺[1] 孙少波[1] 贾军涛[1] 张艳[1] 

机构地区：[1]吉林大学地球科学学院,吉林长春130061

出　　处：《新疆地质》2006年第4期373-376,I0013,共5页Xinjiang Geology

摘　　要：应用牙形石色变指标（CAI）对塔里木盆地孔雀河斜坡东北段南雅尔当山剖面奥陶系有机质成熟度进行了研究。得出的结果是南雅尔当山却尔却克组产出的牙形石色变指标CAI值为2—2．5，有机质处于成熟阶段鲸合研究认为，本区奥陶系烃源岩在中奥陶世逐渐进入生烃门限并快速成熟；在奥陶纪末达到经历的最大古地温，顶部为80℃，底部为180℃，之后遭受抬升剥蚀，区域剥蚀量在2300m左右．本区奥陶系烃源岩存在3种生烃类型：第Ⅰ为南雅尔当山型，为非有效烃源岩；第Ⅱ种为群克1井部分生烃型，舆陶纪末抬升剥蚀后埋深在2500m以上的烃源岩（Ⅱ-1型）停止生烃，埋深在2500m以下的烃源岩（Ⅱ-2型）持续生烃；第Ⅲ种为二次生烃型，当中新生代的快速沉积使Ⅱ-1型烃源岩项部埋深达到3200m时，相同层位的烃源岩达到经历的最大古地温，开始二次生烃，生烃潜力最大．Conodont Color Alteration Index （CAI） is used in this article to analysis the maturity of organic matter in Nanyaerdanshan cross section, Northeastern Kongquehe slope, Tarim basin. The value of conodont CAI of Queerqueke Formation, Nanyaerdanshan cross section, ranging from 2.0 to 2.5, indicates that organic matter has matured. Source rocks of Ordovician reached hydrocarbon generating threshold gradually and matured quickly in middle Ordovician. Then, the source rocks experienced the highest paleotemperature at 80℃ on the top and 180℃ at the bottom in the end of Ordovician. The succeeding uplift of the district led to a denudation of about 2300m. Three kinds of hydrocarbon generating types have been identified in the Ordovician source rocks; First, Nanyaerdangshan type, which had not get the chance to generate hydrocarbon; Second, Qunke 1 type, when the shallower than 2500m source rocks （ Ⅱ-1 type ） stopped to generate hydrocarbon, this kind source rocks which buried deeper than 2500m （ Ⅱ-2 type） continued to generate hydrocarbon after the denudation in the end of Ordovician. Third, hydrocarbon regeneration type, when the Ⅱ- 1 type source rocks was buried more than 3200m after the fast deposition in Mesozoic and Cenozoic, the highest paleotemperature triggered the hydrocarbon regeneration. The third kind of source rocks exhibit the most strong hydrocarbon generation potential among all the source rocks in the area.

关 键 词：牙形石 CAI 南雅尔当山 奥陶系 有机质成熟度 

分 类 号：P618.13[天文地球—矿床学]