| 1H-pyrrole-2,5-diones(maleimides)is a tetrapyrrole compound in petroleum,sediments,rocks,and soil,mainly derived from chlorophylls and bacterial chlorophylls.And it is a new biomarker in petroleum geochemistry.This paper selects source rock and crude oil samples from several basins domestic and overseas,to studiy their distribution and significance in different depositional environments,deepen and expand the application of pigment biomarkers in oil-oil and oil-source rock correlation,and initially explores 1H-pyrrole-2,5-diones for tracing the oil migration and filling orientation.The results show that 2-methyl-3-n-propyl(Me,n-Pr)and 2-methyl-3-isobutyl(Me,i-Bu)maleimide have been confirmed primarily derived from the bacterial chlorophylls in green phototrophic sulfur bacteria(Chlorobiaceae),which can be used to identify the occurenece of light-premeable stagnant water zone.Me,i-Bu/Me,Et and Me,n-Pr/Me,Et and other pigment parameters can well distinguish marine,brackish and salt water,Liushagang formation in Beibuwan Basin is deposited under sub-oxic to oxic water column,Nengjiang formation in Songliao Basin and early Shahejie Formation in Bohai Bay Basin were brackish to salt lacustrine environment with various degrees of water stratification,and the Napo formation in the Orient Basin is a marine environment(shallow water,light-premeable,stagnant water and restricted).The results of oil-source correlation show that class A crude oil are mainly from oil shale,4-methyl-24-ethylcholestane,Me,i-Bu and Me,n-Pr maleimide are developed,class B is mixed crude oil,and Class C crude oil is derived from mudstone.Me,Me/Me,Et maleimide and ?-benzo/ ?-benzo maleimide as new indicators are first proposed.The Cretaceous crude oil migration direction on the east side of MARIANN fault in T block of Orient Basin is generally charged from south to north,and the charging point is located in the southeast of the block. |
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