关键词: 黄骅坳陷, 地球化学特征, 原生油藏, 煤成油气藏, 挤压—逆冲

Abstract: Recently,commercial oil and gas have been produced from the Konggu No.3 well in the Ordovician and from the Konggu No.4 well in the Mesozoic in Kongxi area of Huanghua depression.The successive discoveries of these two wells are the first breakthorugh in the industrial exploration on Paleozoic oil and gas reservoir in Huabei area for several decades.It indicates that the Paleozoic oil and gas reservoirs in Huanghua depression and Huabei are good exploration prospects.Through the systematic study on physical properties and geochemical behavior of crude oil from these two wells,it was found that there are two kinds of oil in this area,which indicated that their oil sources were from different places.It is firstly clarified that crude oil from Ordovician in this area is a mature heavy oil with low pour point,which is genetically associated with Paleozoic hydrocarbon source.This is a primary reservoir,but the crude oil in the Mesozoic is a mature light oil with low pour point and the associated gas is coal-type gas,which is genetically related to upper Paleozoic coal series,and belonged to the coal-formed hydrocarbon reservoir,It is indicated by the study that the formation of these two kinds of reservoir is closely related to the background of reversed tectonics with paleo-compression and modern-extension,paleo-high position and modern-low position.The effect of the compression and thrusting in the Indosinian-Yanshan movement is a key to the formation of oil and gas reservoirs.

Key words: Huanghua depression, geochemical behavior, primary reservoir, coal-formed reservoir, extrusion and thrust