【摘要】 深水低勘探领域是当今世界油气勘探关注的热点之一,有效烃源岩发育程度是低勘探领域烃源岩早期评价首先需要回答的关键问题。而低勘探领域钻井稀少,缺乏采样分析资料,严重制约着烃源岩早期预测。针对这一严峻挑战,本文在借鉴邻区井孔实测资料的基础上,充分利用层序地层学、有机地球化学和地球物理技术,探讨了以多项烃源岩参数为主的5项烃源岩早期预测评价方法,即:1利用层序地层分析方法确定有利烃源岩发育层段;2利用地震速度-岩性定量预测方法确定烃源岩厚度;3利用地震绝对速度定量估算烃源岩成熟度Ro;4运用地震相转沉积相,再由沉积相转有机相方法预测烃源岩有机相类型和分布;5烃源岩层段综合评价优选。应用该方法对华光凹陷渐新统崖城组烃源岩进行了烃源岩早期预测,发现崖城组各段烃源岩厚度具有北厚南薄的特征,崖二段烃源岩最厚可达450m;崖城组烃源岩热演化程度整体较高,受埋深影响,崖三段烃源岩Ro值最高;崖二段浅海相烃源岩分布范围最大,滨岸平原沼泽相最窄,崖一段和崖三段浅海相烃源岩分布范围小,但滨岸平原沼泽相烃源岩分布最宽,并且扇三角洲分流平原沼泽相烃源岩分布较广;烃源岩综合评价分析认为崖二段是最有利烃源岩,崖一段和崖三段是较有利烃源岩。更多还原

【Abstract】 Low exploration area in deepwater is one of the hot issues in oil and gas exploration nowadays.The development of effective hydrocarbon source rock is a first key question to be answered in early evaluation for source rock of low exploration fields.However,scarce drilling and lack of sampling analysis data have seriously been restricting early evaluation of source rock in low exploration area.In response to this challenge,this article has discussed early prediction of source rock and evaluation method with multiple source rock parameters using borehole data in adjacent areas,sequence stratigraphy,organic geochemical and geophysical technology.And this methodology includes five aspects:(1)using sequence stratigraphy to determine the main interval of source rocks;(2)quantitative prediction method of seismic velocitylithlogy to determine the thickness of source rocks;(3)prediction of vitrinite reflectance with mudstone absolute velocity to determine the maturity(Ro)of source rocks;(4)type prediction of organic facies based on the conversion from seismic facis to sedimentary facies and organic facies;(5)comprehensive evaluation to select optimum hydrocarbon generating depression.These methods are also applied to early prediction of the source rocks of Oligocene Yacheng Formation in the Huaguang depression.The results indicate that the thickness of source rock in the Yacheng Formation shows a decrease from north to south,and source rocks is up to 450 mof thickness in the second member of the Yacheng Formation.Thermal evolution degree of source rocks is very high overall in the Yacheng Formation.Influenced by the burial depth,the maturity degree(Ro)of source rocks in the third member of Yacheng Formation is the highest.The covered area of hydrocarbon source rock with shallow sea facies is the biggest,but shore swamp facies is the narrowest in the second member of Yacheng Formation.In addition,the distribution area of source rock with shallow sea facies is small,but shore swamp facies is wide in the first and third member of Yacheng Formation. Meanwhile,source rocks of fan delta swamp facies are widely distributed.Comprehensive evaluation suggests that the source rocks in the second Member of Yacheng Formation is the most favorable and source rocks in the first while the third Member of Yacheng Formation is less favorable.更多还原