塔北地区油气藏上方烃类垂向微运移的证据和特征

通过对塔里木 盆地北部地区地表土壤、多口井不同深度的岩屑、原油及油藏上方天然气进行了轻烃组分、轻烃指纹荧光光谱、甲烷碳同位素、井中岩屑酸解烃和轻烃垂向分布研究,以及对钻井岩屑的磁化率、磁滞回线、磁性组分及蚀变矿物等蚀变矿化特征的研究,证实该区在5000m之下的油气藏中的烃类组分仍可垂向运移到地表;深层烃类通过微垂向运移,可在油气藏上方及其地表形成多种可测量到的物化探异常。

The Evidence and Characteristics of Vertical Micro-Migration of Upper Pool's Hydrocarbons in Northern Tarim Basin

The hypothesis of"Stack effect"is fundamental basis for directly finding out reservoir by means of techniques of non-seismic geophysical prospecting and geochemical prospecting.The study,of direct information such as surface soil,multiwell cuttings of different depth,light hydrocarbons constituent,fingerprint fluorescence spectrum,methane carbon isotope,lithic acidolysis hydrocarbon and vertical light hydrocarbon distribution that indicate existence of deep oil reservoir,of indirect information as magnetic capacity,magnetic hysteresis loop,magnetic component of drilling cuttings and altered mineral/mineralization that reveal vertical micro-migration of hydrocarbons,show that in northern Tarim area,its hydrocarbon constituent existed in oil reservoirs buried beneath5000m could still move up to the surface vertically,under effect of which,various geophysical and geochemical anomalies that can be detected over the oil reservoirs and subsurface.