深部热流体对油气成藏的影响

深部热流体是一种由多元组分构成的超临界流体 ,其上升活动可使地球内部的物质与能量发生调整或再分配。对油气而言 ,深部热流体携带的高热能可使沉积盆地的古地温升高 ,加快烃源岩的热演化进程 ,增加有效烃源岩的体积 ,促进烃类的生成 ;在上升过程中 ,因其具很强的溶解和扩散能力 ,故可萃取、富集沉积物中的分散有机质 ,同时又对生烃产生显著的加氢作用 ,从而为油气的形成补充物源。此外 ,热流体与围岩储层发生化学反应 ,可改善储层的孔渗条件 ,有利于油气的聚集成藏 ,而且因其具有较高的压力和含水量 ,可抑制烃类的热裂解而有利于油气的保存。

Influences of Deeply Sourced Thermal Fluid on the Formation of Hydrocarbon Reservoirs

Deeply sourced thermal fluid is a kind of supercritical fluid composed of several constituents. Rising upward, it can transmit energy and material, and regulate and redistribute them in the inner Earth. For the formation of oil and gas, hypogene hydrothermal fluid can increase the paleotemperature of depositional basin, accelerate the evolution history of source rocks and enlarge the volume of effective source rocks. It can also extract and enrich dispersive organic matter in sediments because of its higher dissolving and diffusing capacity, and obviously contribute hydrogen to hydrocarbon generation. So the deeply sourced thermal fluid provides part of material resources for hydrocarbon generation. In addition, the reaction between thermal fluid and surrounding rocks can improve their porosity and permeability. This is favorable for the migration and accumulation of hydrocarbons. Moreover, that the higher pressure and water content of thermal fluid can significantly retard the thermal destruction of hydrocarbon is advantageous to the preservation of oil and gas.