强烈风化作用对烃源岩评价指标的影响——以额济纳旗及邻区石炭系—二叠系为例

摘要

通过对雅干地区4口浅钻井样品与二叠系埋汗哈达组、阿其德组和哈尔苏海组露头样品、XT9井岩心样品、大狐狸山剖面干泉组露头样品的有机质丰度、类型、成熟度等烃源岩评价指标的对比研究,认为强烈风化作用对烃源岩有机质丰度和常规有机质类型评价指标(H/C-O/C)的影响范围超过50m,且对有机质丰度各评价指标的影响程度不尽相同,对TOC含量的影响最小,对生烃潜量的影响最大；生物标志化合物指标受风化作用的影响较小,能对露头样品有机质类型进行有效划分.风化作用对镜质体反射率(R0)的影响范围在10m以内.%Based on a comparative study of the hydrocarbon source rocks evaluation indexes of organic matter abundance, type and maturity between samples from four shallow drill holes and outcrop samples of Permian Maihanhada Formation, Aqide Formation and Haersuhai Formation, and between core samples of XT9 well and outcrop samples of Ganquan Formation of Dahulishan section, the authors hold that the influence range of intense weathering on the source rocks evaluation indexes of organic matter abundance and normal type (H/C-O/C) is over 50m, and the extents of influence on various evaluation indexes are somewhat different.The influence on TOC is minimum, the influence on the potential hydrocarbon generation amount is maximum, and the influence on the biomarkers indexes is comparatively insignificant. On such a basis, organic matter types of outcrop samples can be effectively divided. The influence range of intense weathering on the vitrinite reflectance (Ro) is less than 10 m.