【摘要】 根据测井、地震及实验分析数据,分析贝尔凹陷南屯组优质烃源岩-钙质泥岩层的识别特征和地质成因.结果表明,钙质泥岩层具有高自然伽马、高电阻率、高声波时差、低密度的"三高一低"响应,在地震剖面上为连续强反射;该层形成于广阔湖盆、微咸水、深水沉积环境,沉积稳定且范围广,是凹陷重要的地层对比标志层;岩性主要为灰黑色泥岩,局部夹杂油页岩和泥灰岩,富含钙质(主要为碳酸盐矿物,其次为介形虫等生物化石)和藻类,有机质类型为Ⅱ1-Ⅰ型,丰度高,是凹陷最优质的烃源岩层.该层与南屯组低水位域湖底扇和高水位域扇三角洲前缘进积扇体形成最有利的成藏组合,油气最为富集,其平面展布范围控制油气的平面分布,为贝尔凹陷等断陷盆地的油气勘探提供新认识.更多还原

【Abstract】 By laboratory analysis of seismic and log data,identification characteristics and geological formation of calcareous mudstone strata-the high-quality source rock of Nantun group in Bei’er sag havebeen researched.Its electrical measurement characteristics are manifested as high natural gamma ray and high resistance and high interval transit time and low density,summarized as "three high and one low".There is a continuous strong reflection on a seismic profile.The layer is formed in the brackish water,wide lake basin,deep-water sedimentary environments,depressed steadily and widely,also an important stratigraphic correlation marker in the sag.The layer mainly includes gray-black mudstone,partially mixed up with oil shale and marl,is rich in calcium(mainly carbonate minerals,secondly ostracoda fossils etc.)and algae fossils.It has high abundance and is the best high-quality source rock in the whole sag with organic typeⅡ1-Ⅰ.The layer formed the best favorable reservoir combination rich in oil and gas with the sublacustrine fan in low water level domain and delta front progradation fan body in high water level domain of Nantun group.The distribution range of calcareous mudstone strata controls the plane distribution of oil and gas.The research provides new understandings and effective practices for oil and gas exploration of faulted basins as well as Bei’er sag.更多还原