整体封存体系的内涵

天然气易于散失的特性,决定了整体封存体系的高标准、严要求,评价的思维应以板桶理论(木桶效应)为指导,特别要重视局部对整体的决定作用。天然气的封存与石油不同,整体封存体系的内涵,必须强调结构的立体性与功能的有效性。川东、川东北的油气勘探实践表明,下部(中、古生界)的超压流体系统与上部(中、新生界)的高压-静压流体系统,共同构成整体封存体系的立体性,实际是一个物性、浓度、压力为一体的复合封闭结构。有效性取决于:(1)埋深;(2)区域水动力;(3)晚期抬升;(4)抬升时限。立体性为构建,有效性为改建,只有二者的统一方能发挥整体封存的最大功能。

INTENSION OF BULK SEALING OFF SYSTEM

High standard and strict requirement for bulk sealing off system have been determined by nature of easily loss of natural gas.Evaluation of the thinking shall be guided by the theory of board bucket (wooden bucket effect) and more attention shall be paid to the decisive role of locality over bulk in particular.With distinction between sealing off of natural gas and petroleum,emphasis must be placed on stereo and effectiveness when mentioning intension of bulk sealing off system.practical oil and gas exploration in eastern and northeastern Sichuan indicates that overpressure-static pressure fluid system in the lower part(Mesozoic-Palaeozoic) and high pressure-static pressure fluid system in the upper part (Mesozoic-Cenozoic) jointly constitute the stereo of bulk sealing off system,in fact a combined-sealing off system is composed of physical property,concentration and pressure.Effectiveness is decided by (1).buried depth;(2).regional hydro-dynamics;(3).late uplift;(4).time limit of uplift.Stereo is constitution and effectiveness is reconstruction,only by putting these two into one,can maximum function of bulk sealing off system be fully brought into play.