碎屑岩储层物性与成岩作用密切相关,压实作用是成岩作用的重要组成部分,是储层物性降低的主要因素之一。为对地质历史时期压实作用条件下储层物性变化进行定量化表征,通过物理模拟实验,分别研究了在压实作用下不同地温条件和不同埋藏方式下砂岩储层孔隙度和渗透率的变化规律。研究结果表明:在砂岩物源相同,分选、磨圆类似的前提下,砂岩孔渗参数与地温均呈对数负相关关系,且地温梯度越高,孔渗参数随埋深的下降速率越大。即使是在相同的埋藏终止条件下,随着埋藏时间增加,岩石抗压能力会发生下降,骨架颗粒会趋于定向排列,从而导致岩石孔渗参数呈随埋藏时间增加呈对数减少。在不同的沉降过程条件下,即使处于同一地温场,并且埋藏终止状态相同,经历过构造抬升的砂岩物性明显要差于持续埋藏的砂岩物性。
The physical properties of clastic reservoirs are closely related to diagenesis,while compaction,a principal component of diagenesis,is one of the important factors to reduce reservoir physical properties.In order to characterize quantitatively the variation of the physical properties of clastic reservoirs during compaction in the geological history,the porosity and permeability characteristics of clastic reservoirs with different burial temperature and different burial processes were precisely characterized based on the physical simulation experiment.The results show the porosity and permeability of clastic rocks are in logarithmic relationship with burial temperature and the higher the geothermal gradient,the higher the reduction rate of porosity and permeability on the premise of the same source rock,similar sorting and roundness.The anti-compaction of reservoirs declines with the increase of the burial time under the condition of the same burial depth and the matrix particles tend to be oriented,resulting in a logarithmic decrease in the porosity and permeability of reservoirs.For the different subsidence process,the physical properties of reservoirs suffering the tectonic subsidence are obviously worse than that continuously buried,even if in the same condition of geothermal gradient and burial depth.