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

摘要： 黄骅坳陷孔西地区孔古3井奥陶系地层及孔古4井中生界地层相继获工业性油气流,是几十年来华北地区古生界油气藏工业性勘探的首次突破,揭示出在黄骅坳陷以及华北地区古生界油气藏具有良好的勘探前景.通过对这两口井原油物性、地化特征的系统研究及与煤系烃源岩的综合对比分析,认为该区存在着两类原油,反映其油源来自不同母源,首次阐明该区奥陶系原油为低凝重质成熟原油,与古生界烃源岩具有成因上的联系,属原生油藏;而中生界原油为低凝轻质成熟原油,原油伴生天然气为煤型气,与上古生界煤岩有成因上的联系,属煤成油气藏.研究表明,这两类油藏的形成与其古压今张、古高今低的反转构造背景密切相关,印支-燕山期的挤压逆冲作用是油气成藏的关键.

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