Effective source rock identification and application—Case of Tarim basin

Since long ago effective source rocks have been defined as rocks that have generated and discharged hydrocarbon and the discharged hydrocarbon can form commercial hydrocarbon reservoirs.In Tarim Basin where exploration degree is not very high,for exploration effective guiding convenience,this paper has defined and identified effective source rocks based on potential source rocks(dark mudstone,limestone,marl and coal measures strata with hydrocarbon generation ability).The effective source rocks in Jurassic and Carboniferous are potential source rocks in which Ro0.5% and organic carbon0.5%.Potential source rocks in Cambrian and Ordovician that can have primary hydrocarbon generation possibility or secondary hydrocarbon generation potential are regarded as effective source rocks.Identification of effective source rocks usually depends on geochemical parameters of well site such as organic carbon content.As to area with multi-well sites,scope of effective source rocks can be precisely defined according to organic geochemical index of well sites.Exploration degree of Tarim Basin,however,is not high,so effective source rock distribution cannot be precisely defined only by geochemical index of the well sites.Since development of source rocks is closely related to sedimentary environment,the distribution scope of effective source rocks can be defined on the plane through sedimentary facies belt extension and be finally identified by considering the burial history of source rocks at the same time.