低勘探程度地区烃源岩综合评价——以塔里木盆地西南拗陷石炭系烃源岩为例

摘要

综合考虑烃源岩沉积时的内在属性和沉积之后的外在演化两个方面,筛选烃源岩厚度、总有机碳含量及镜质体反射率评价参数,并提出等效有机碳厚度概念,利用等效有机碳厚度和镜质体反射率参数的交会叠合,建立了低勘探程度地区烃源岩综合评价方法.运用此方法对塔里木盆地西南拗陷石炭系烃源岩进行综合评价,预测最有利烃源岩位于研究区的乌恰—喀什—阿克陶和莎车—泽普—叶城一带.该方法预测的有利烃源岩区域与目前的勘探现状吻合,显示了此评价方法在低勘探程度地区的可行性.%The low-exploration area is important for petroleum exploration in future with abundant oil and gas resources.And the source rock plays a critical role in those area.In this paper,given that the intrinsic property and external evolution of source rock,several parameters are chosen that are closely related with source rock,such as thickness,total content of organic carbon and vitrinite reflectance.The concept of equivalently organic carbon thickness was proposed firstly.And a comprehensive evaluation method of source rock in lowexploration area is built based on the intersection of equivalently organic carbon thickness and vitrinite reflectance.A case study on the major source rock of Carboniferous mudstone in southwest sag of Tarim Basin shows that the best source rock lies in the Wuqia-Kashi-Aketao and Shache-Zepu-Yecheng region.The best source rock predicted by this method basically coincides with the present exploration result.Moreover,the new comprehensive evaluation method was proved of great reliability.