深部流体对天然气成藏影响

深部流体是地球内部物质和能量交换最活跃的组分,超临界状态存在的深部流体中含有大量的气体,通过地震、火山或以其他各种构造通道向地球的浅部运移。上升过程中由于物理化学条件变化(主要是温度和压力降低),其中的挥发分首先从岩浆中析出,在合适的构造部位直接聚集成藏;同时流体上升过程中带出的大量地球深部的物质或能量为天然气形成提供有利条件。中国东部郯庐大断裂带气藏天然气碳同位素及稀有气体地球化学特征表明,深部流体直接或间接对天然气形成以及运移有重要的影响。国外一些天然气形成的模拟实验结果也显示以二氧化碳和水为主的流体在深部油气的无机合成、运移和富集中起着重要的作用。深入研究深部流体与天然气形成之间的关系可以为天然气勘探提供重要的方向和目标,将对天然气成因及来源产生重要的理论和实践意义。

EFFECTS OF DEEP-SOURCED FLUIDS ON THE FORMATION OF NATURAL GAS RESERVOIRS

The deep-sourced fluids are important in material and energy transfer on earth interior.Deep-sourced fluid is a kind of supercritical fluid composed of vast of gases.These gases will move to the shallow through earthquake or deep fault belt.The temperature and pressure will reduce during the fluid uplifting.A mass of gases will extract from fluid or magma.On the other hand,it can transmit energy and material,which obviously contributes hydrogen to hydrocarbon generation.Appling models of stable carbon isotope and rare gas geochemistry,the natural gases along Tanlu Fault Belt were studied.The result shows that the deep-sourced fluid effects on natural gas formation and migration.The same result was obtained with an experimental simulation of natural gas formation.The recent researches on the relationship between deep-sourced fluids and the formation of natural gas reservoir have important theoretic and practice significance to natural gas origin.