Potential of palaeofluid analysis for understanding oil charge history

摘要

Fluid inclusion data, particularly the distribution of hydrocarbon fluid inclusions and their chemistry, can provideninsights into oil charge in a petroleum-prospective region. Examples from the UK Atlantic margin show how wencan understand thermal regime, timing and chemistry of oil charge. Data from the UK Atlantic margin based onnfluid inclusion temperature profiles shows anomalously high temperatures which are highest at the top of the Tri-nassic–Eocene sequence. This is interpreted as a product of hot fluid flow, probably reflecting hydrothermal activitynrelated to intrusion of sills at depth. The preservation of high temperatures also implies rapid migration fromndepth through fracture systems. Ar–Ar analysis of oil-bearing K-feldspar cements, and petrographic studies of oilninclusion distribution help delimit timing and migration pathways for the hot fluid charge and later fluid migrationnevents. Coupled with compositional data for oils measured destructively (organic geochemistry) or non-destruc-ntively (fluorescence), these approaches allow the development of oil charge histories based on real data rathernthan theoretical modelling.