南华北盆地平顶山地区己五井上古生界煤系烃源岩评价

摘要

南华北盆地平顶山地区上古生界煤系地层具有良好的非常规油气藏的勘探前景,但对该地区潜在烃源岩缺少系统的评价.选取平顶山地区上古生界揭露较全的全取心己五井(PJ5),对上古生界煤岩、泥岩和碳酸盐岩系统地取样,并进行有机碳、岩石热解、氯仿沥青“A”、有机显微组分、镜质体反射率和干酪根碳同位素分析.结果表明,平顶山地区己五井上古生界烃源岩不仅包括煤岩,而且泥岩和碳酸盐岩均可作为潜在烃源岩.纵向上,烃源岩主要分布于太原组和山西组的下部,较为连续.山西组上部、下石盒子组和上石盒子组烃源岩主要分布在煤层(线)附近,连续性较差;平顶山地区己五井上古生界烃源岩不仅煤岩和泥岩的有机质类型为Ⅲ型,而且碳酸盐岩的有机质类型也以Ⅲ-Ⅱ2型为主;平顶山地区己五井除上石盒子组处于低成熟阶段外,以下层位均达到成熟阶段,Ro值具有随深度增加而逐渐增大的趋势.%Upper Paleozoic coal-bearing strata has a good exploration prospect of unconventional hydrocarbon reservoirs in Pingdingshan,Southern North China basin,however there lacks systematic evaluation of potential source rocks in this area.In this study,full coring PJ5 which fully drilled Upper Paleozoic was selected for analysis.Coal rocks,mudstones and carbonate rocks of Upper Paleozoic was sampled systematically.The TOC,rock rock-eval pyrolysis,chloroform asphalt "A",organic maceral,vitrinite reflectance and kerogen carbon isotopes was analyzed.The results show that in addition to coal rocks,mudstones and carbonate rocks are potential source rocks of the Upper Paleozoic in PJ5.This source rocks vertically continuously distribute in Taiyuan Formation and the lower part of Shanxi Formation,and discontinuously distribute in the upper Shanxi Formation,Xiashihezi Formation and Shangshihezi Formation close to coal seam (line).The kerogen type of coal rocks and mudstones are Ⅲ type and the carbonate rocks are mainly Ⅲ-Ⅱ2 type of the Upper Paleozoic source rocks of PJ5 in Pingdingshan.Excepts Shangshihezi Formation of PJ5 in Pingdingshan which maturation of evolution is at low stage,the lower layers of Shangshihezi Formation all reach mature stage and Ro increases along with depth.