烃类垂向微运移的地球化学效应及其机理讨论

烃类垂向微运移(盖层及其上部)形成近地表烃类异常是油气化探的理论基础和应用前提.烃类垂向微运移的客观存在表明地表化探异常为"有源之水".油气藏不同部位微运移的差异性揭示了油气化探的有效性.文中依据地表和井中地球化学成果,根据油气井中普遍存在的烃类向上趋轻的结构梯度和各指标正向运移梯度及晕源对比,揭示了烃类垂向微运移的客观存在,强调了微裂缝网络系统的重要性,对微运移机理进行了讨论,较好地解释了地表化探异常的成因机理. 

STUDY ON THE GEOCHEMICAL EFFECTS OF VERTICAL HYDROCARBON MICROMIGRATION AND THEIR MECHANISM

Vertical hydrocarbon micromigration (caprock and above) resulting in near-surface hydrocarbon anomalies is the theoretical basis and applied premise of geochemical hydrocarbon exploration. The objective exi-stence of vertical hydrocarbon micromigration showed that surface geochemical exploration anomalies were like "a river with sources". The differences of micromigration in the different parts of oil and gas pools revealed the effectiveness of geochemical hydrocarbon exploration. Based on teh geochemical fruits of surface and drilled wells and according to the positive migration gradient of various indexes,the correlation of halo sources and the structural gradient that hydrocarbon is getting lighter upwards,which is widespread in oil and gas wells,the objective existence of vertical hydrocarbon micromigration was revealed,the importance of microfracture network systems was emphasized,the mechanism of micromigration was discussed,and the genetic mechanism of surface geochemical exploration anomalies was well interpreted in this paper.