凝析油藏充注方向示踪分子标志物:烷基二苯并呋喃

Molecular Tracer Markers for Filling Pathway in Condensate Reservoirs:Alkyldibenzofuran

石油中的二苯并呋喃(DBF)及甲基二苯并呋喃(MDBF)具有和二苯并噻吩(DBT)和二苯并吡咯(咔唑)化合物类似的结构和性质,其异构体相对含量和总量既受热成熟作用的影响,又受运移分馏效应的控制。以氘代二苯并噻吩为标样,求得二苯并呋喃和烷基二苯并呋喃类化合物的绝对含量,其与咔唑类含氮化合物总量呈很好的正相关性。以北部湾盆地福山凹陷花场凝析油藏为实例的油藏充注方向示踪结果表明,二苯并呋喃类化合物总量可以作为良好的油藏充注示踪参数。对常规甾萜类生标物参数不准确甚至失效、含氮化合物总量误差较大的凝析油藏而言,烷基二苯并呋喃类含氧芳烃化合物不失为一类有效而又易得的替代示踪标志物。

Dibenzofuran(DBF) and methyl dibenzofurans(MDBFs) had similar chemical structures and features of dibenzothiophenes and carbazoles.The relative contents of different isomers were influenced by thermal maturation,and controlled by migration fractionation as well.By using D-substituted dibenzothiophene as standard,the absolute concentration of dibenzofuran and alkyl-dibenzofurans were determined.The absolute concentration of dibenzofuran and methyl-dibenzofurans were positive correlation to that of pyrronic nitrogen compounds.The oil migration orientation and filling pathway of the Huachang Condensate Reservoirs were studied in Fushan Depression of Beibuwan Basin.It indicates that the newly developed molecular geochemical parameters——the absolute concentration of dibenzofuran compounds of oils can be used as geochemical parameter for tracing the oil migration orientation and filling pathway.For most condensate reservoirs,the steranes and terpanes related parameters are not accurate or invalidate for extremely lower biomarker concentrations.The total contents of nitrogen compounds are also not accurate for their much lower contents of NSO fractionation.Under this situation,the alkydibenzofuran compounds can be used to substitute molecular markers to trace the filling pathway and migration orientation of light oil of condensate reservoirs.