延吉盆地铜佛寺组烃源岩地球化学特征及勘探潜力评价

Source Rocks Geochemical Characteristic and Exploration Potential Evaluation of Tongfosi Formation in Yanji Basin

延吉盆地为中生代断陷盆地。根据20口岩心及测井资料分析,延吉盆地铜佛寺组主要发育扇三角洲相和湖泊相2种沉积相类型,暗色泥岩厚度达20~500m。基于对700余块铜佛寺组暗色泥岩样品的有机碳、氯仿沥青＂A＂、生烃潜量、有机质类型的测试数据,确定出铜佛寺组一段、二段、三段都发育有较高有机质丰度的烃源岩,有机质类型以Ⅱ型为主。90块暗色泥岩的RO值测试数据表明,铜佛寺组暗色泥岩除德新凹陷铜佛寺组三段部分样品未达到生油门限外,其余都处于开始生烃的低熟—成熟阶段。综合各种测试分析数据,认为延吉盆地除了德新凹陷铜佛寺组三段为低熟烃源岩之外,铜佛寺组暗色泥岩均为成熟良好的有效烃源岩。综合烃源岩特征及有效烃源岩分布等,认为延吉盆地具有良好的油气资源潜力,并依据油气显示（产量）、沉积相、圈闭类型等5个评价参数,优选出延吉盆地Y13井—Y20井区、延10井—延12井区、Y1井—Y3井区为勘探开发有利区。

The Yanji Basin is a Mesozoic fault basin.Based on cores and well logs of 20 boreholes,facies of the Tongfosi Formation are mainly fan-delta and lacustrine.Thickness of dark-colored mudstone ranges from 20 to 500m.Analyses of organic carbon,chloroform bitumen ＂A＂,hydrocarbon generation potential,and organic matter type on more than 700dark-colored mudstone samples show that,source rocks of the First,Second,and Third members of the Tongfosi Formation have relatively high organic matter concentration and are characterized by type-Ⅱ kerogen.Results of organic maturity degree（RO）analysis on 90 darkcolored mudstone samples show that,apart from part of the third member in the Dexin Sag,most of the dark-colored mudstone of the Tongfosi Formation in the Yanji Basin is slightly mature or mature,and is interpreted as effective source rock.Thus,the Yanji Basin is a potentially productive petroliferous basin.Based on five evaluation indices,such as hydrocarbon production,facies,and trap types,a series of well blocks（i.e.,Y 13 to Y 20,Yan 10 to Yan 12,and Y 1to Y 3）are selected as priority prospects.