沉积盆地活动热流体类型及其石油地质意义

Hydrothermal Fluids Flow Types in Sedimentary Basins and Its Significance of Petroleum Geology

热流体是沉积盆地物质和能量传输的重要载体 ,其活动可使盆地内的物质和能量发生调整或再分配。根据热流体活动通道 ,将沉积盆地活动热流体类型划分为侧向对流型、垂向对流型和侧向 -垂向对流复合型。活动热流体改变了盆地的温、压场 ;对有机质演化和油气生成具有重要的强化作用 ,使在单一传导背景下不可能成熟的地层进入生烃门限 ,扩大了有效烃源岩的层位和体积 ;改变了成岩 -孔隙演化 ,形成大量次生孔隙 ,改善了储层 ;热流体底辟不但形成了大量断裂和微裂缝 ,而且可形成背斜构造 ,有利于油气的运移与成藏 ;能量强的活动热流体底辟可破坏油气藏。因此 。

Hydrothermal fluids are the carrier of substance and energy; its flow could adjust or reallocate the substance and energy of the sedimentary basin. According to the major controlling factor, passage of fluid migration, it divides hydrothermal fluids flow into three types: (1) lateral convection type; (2) vertical convection type and (3) lateral and vertical compound type. Hydrothermal fluids flow have significance to petroleum geology: (1)changed the fields of temperature and pressure; (2) significantly enhanced organic-matter maturation and petroleum generation, leading strata that would be immature in conductivity setting to go beneath the threshold depth for petroleum generation, enlarging the interval and volume of effective source rocks; (3) affected the evolution of diagenesis and porosity, and shaped many second porosity that meliorate the reservoir; (4) diapir formed not only a many of faults and microfractures which were the passage of petroleum migration, but anticline structures which maybe traps of petroleum; it could also destroy the oil/gas pool if its energy was powerful.