文昌凹陷优质烃源岩地化特征与生烃潜力

文昌凹陷为珠江口盆地西部主体凹陷,主要包括文昌A凹陷与文昌B凹陷,面积约4000km2,该凹陷及其周缘累计发现原油地质储量超过1亿m3,天然气约300亿m3,为证实的富生烃凹陷。主要发育"两类、三型"即文昌组、恩平组两大类,具体分为文昌组中深湖相源岩、文昌组滨浅湖相源岩及恩平组河沼相源岩三种类型;近年钻探的文昌19-1M-X井首次揭示了该凹陷生烃门限以下文昌组湖相优质烃源岩的存在,为重新厘定凹陷生烃潜力提供新的证据。本文通过对进入生烃门限和未进入生烃门限优质烃源岩进行对比研究,并结合盆地模拟手段分析认为:始新世-渐新世早期欠补偿沉积背景及沉积-构造控制下的古湖泊旋回特点致使文昌组地层形成具备优质烃源岩地化特征的生油岩;文昌A凹陷为油气并举凹陷,偏气;文昌B、C凹陷及琼海凹陷周缘地区成熟烃源岩以文昌组为主,且主生油。

The geochemical characteristics and hydrocarbon generation potential of the high-quality source rock in Wenchang sag

As a principal part of the Western Pearl River Mouth Basin,Wenchang Sag mainly includes Sag A and B.It is about 4000km2.We discovered that its accumulative total petroleum reserves exceed 1.0×108m3,The discovery of natural gas reserves are about 300×108m3 and proved rich hydrocarbon depressions.It mostly developed two kinds source rock:Wenchang group and Enping group.It embodied three sets of source:Wenchang group of deep lacustrine source rock,Wenchang group of shore shallow lacustrine source rock and Enping river swamp facies source rock group.The recent WC 19-1M-Xwell drilled firstly revealed the being of high quality Wenchang group lacustrine source rock following the hydrocarbon generating threshold.So it deepened to the study of the geochemical characteristics and the redefinition of hydrocarbon generation potential,through the contrast research between the coming into hydrocarbon generating threshold and not,combining basin simulation.This paper analyzes that the character of the ancient lake gyre made the WenChang group turn into the high quality hydrocarbon source rock.And