Geochemical Characteristics and Origins of Crude Oil in the North Slope,Bongor Basin,Chad
[Objective]The physical properties and geochemical characteristics of oil found in the Northern slope,Bongor Basin,Chad,are clearly different.This paper aims to determine their differences and the influences on their properties and provide practical guidance for the assessment and prediction of oil quality in future oil exploration in this region.[Methods]The physical properties and molecular marker compounds of 41 crude oil samples from the northern slope belt were analyzed by oil family separation,gas chromatography,gas chromatography-mass spectrometry.[Results and Conclusions]It was found that the degree of biodegradation is responsible for the differences.Non-,slightly-or heavily degraded oils were classified according to the relative content and distribution pattern of normal alkanes and acyclic isoprenoids,as well as the baseline characteristics of gas chromatograms.Burial depth is evident-ly the most important factor constraining the degree of biodegradation.No biodegraded oil was found deeper than 1 300 m;the most heavily biodegraded oil occurs shallower than 800 m.In reservoirs between these depths,the degree of biodegradation is associated with distance from main faults,thickness of local caprock and type of trap.
国家科技期刊平台
NSTL
万方数据
