新疆塔里木盆地孔雀河地区下古生界烃源岩与成烃史分析

塔里木盆地孔雀河地区寒武—奥陶系烃源岩分布广泛,厚度由东北向西南逐渐增大,累计最大厚度达4 000余米,寒武系—下奥陶统烃源岩有机质处于高成熟-过成熟阶段,中上奥陶统烃源岩有机质处于成熟-高成熟阶段.在剥蚀量和古地温研究基础上,通过单井埋藏史与古地温曲线的叠合,总结出孔雀河地区寒武—奥陶系烃源岩的生烃史,共3类7型:第一为二次生烃类,按进入二次生烃时间可进一步分为三型;第二为持续生烃类,按埋藏史可再分为两型;第三为下部过成熟类,按达到过成熟温度(240℃)的时间可进一步分为两型.在所划分的3类7型中只有底部过成熟二型属于不具备生排烃能力的无效烃源岩,这一结果扩大了本区的油气资源前景.

SOURCE ROCK DISTRIBUTION AND HYDROCARBON GENERATION HISTORY DURING EARLY PALEOZOIC IN KONGQUEHE REGION, TARIM BASIN, XINJIANG

Hydrocarbon source rock widely developed during Cambrian-Ordovician in Kongquehe region,Tarim basin.The thickness of source rock increased to more than 4000 m from the northeast to the southwest.Gas was the main product of the high matured-over-matured source rocks in Cambrian-lower Ordovician,while oil was mainly produced in the matured-high matured source rock in middle and upper Ordovician.Based on the study of denudation and the paleo-geotemperature,by comparing the burial history of single well and the paleo-geotemperature curve,the hydrocarbon generation history during Cambrian-Ordovician was classified as three classes,secondary hydrocarbon generation,continuous hydrocarbon generation and over-matured.Furthermore,the secondary hydrocarbon generation was subdivided into three types according to the time of secondary hydrocarbon generation happened.The continuous hydrocarbon generation was subdivided into two types based on the burial history.The over-matured was subdivided into two types based on the sustainable period at the over-mature temperature(240oC).Only the type II of over-matured source rock lost the ability to generate and release hydrocarbon.The result highlighted the resource potential in this region.