脉冲式混相涌流——天然气成藏的一种特殊运移方式

PULSE MISCIBLE PHASE FLOW—A SPECIAL MIGRATION PATTERN OF FORMING GAS RESERVOIR

从流体封存箱的基本概念出发，研究了在高温、高压、封闭地层这一特定地质条件下，产生脉冲式混相涌流这种特殊的天然气运移方式。其原理是：随着异常高压的不断增加，高压带边缘（封存箱顶、底面或侧面）的相对封隔带发生破裂，高压带内的流体———溶解气、水、游离气、油等以混相方式向外涌出；随着压力的下降，油、气、水三相分离，溶解于地层水中的天然气会大量析出，游离气相大量增加；当高压带流体压力得到释放后，破裂的岩层重新闭合而成为新的相对封隔层，当压力再次升高时，又重复上述过程，呈脉冲状周而复始。据此，以莺歌海盆地为实例，分析了其封存箱分布及天然气运聚成藏特征，建立了典型的模式。最后认为。

Based on the fundamental concept of the fluid compartment,a special gas migration pattern—pulse miscible phase flow,formed under certain geological conditions of high temperature,high pressure and confined formation,is studied.Its principle is that along with an unceasing increase in pressure,the relative closed belts around the edges of abnormal high pressure zone,such as the top,bottom and lateral of the compartment,are broken and the fluids in the abnormal high pressure zone,such as the dissolved gas,water,free gas and free oil,may flow off in a manner of miscible phase;along with a decrease in pressure and through three phases (oil gas water)separation,the natural gas dissolved in the formation water would be enormously separated and the free gas may be greatly increased;and when the fluid pressure in the abnormal high pressure zone is released,the broken strata close again and become a new relatively confined formation.When the pressure increases again,the process mentioned above will repeat itself,showing a pulse cycling.By taking the Yinggehai Basin as an example,the characteristics of the compartment distribution and natural gas migration and accumulation are analyzed and a typical model is set up.It is thought that the pulse miscible phase flow is a special migration pattern of forming gas reservoir.