高级检索

    惠民凹陷古近系碎屑岩储层性质主控因素简析

    Main controlling factors of Paleogene sandstone reservoirs in the Huimin subbasin

    • 摘要: 提要:惠民凹陷古近系砂岩储集层物性主要受压实、碳酸盐胶结和溶蚀作用、沉积条件控制。根据铸体薄片、阴极发光薄片、扫描电镜、物性和碳酸盐含量等数据,分析了该区储集层物性的控制因素,对各因素的影响大小和程度进行初步的定量评价。认为压实作用对孔隙度的影响主要表现在埋藏早期或碳酸盐胶结程度低的阶段,埋深每增加1 000 m孔隙度降低8%~9%;胶结作用对储集层性质影响与成岩演化阶段有关,成岩演化程度越高,胶结对物性的影响越大;溶蚀作用对储集层性质改善很大,产生的次生孔隙最大可达20%。溶蚀作用在宏观上受区域构造背景和生油洼陷平面位置控制,断层较发育和临近生油中心(临南洼陷)的南部斜坡带和中央隆起带溶蚀最发育。微观上溶蚀作用受岩石的粒度、分选及杂基含量控制,粒度越粗、分选越好、杂基越少的砂岩溶蚀作用越强。沉积条件对物性的影响主要表现在对原生孔隙的发育程度和对溶蚀、胶结等成岩作用的控制方面。

       

      Abstract: Abstract:The physical properties of Paleogene sandstones reservoirs in the Huimin subbasin are mainly controlled by compaction, carbonate cementation, dissolution and depositional environment. The controlling factors of physical properties of reservoirs are analyzed based on the data from analyses of mold thin sections, cathode luminescence thin sections, scanning electron microscopy, physical properties and carbonate contents of rocks. Preliminary quantitative evaluation of the degrees of influences of these factors has been carried out. It is suggested that:① the porosity decreases by 8%–9% per 1000 m of descent due to compaction at the early burial stage or the stage of low degrees of carbonate cementation; ② the influence of carbonate cementation on the physical properties of reservoirs is related to the diagenetic evolution stages:the higher the degree of diagenetic evolution, the greater the influence of the cements on physical properties will be; and ③ dissolution plays an important role in improving the properties of the reservoirs and the secondary porosity produced by dissolution is up to 20%. However, the dissolution is mainly controlled by the regional tectonic setting and the position of the hydrocarbon-producing subbasin and the dissolution is relatively stronger in the central uplift zone and the south slope zone near the hydrocarbon-producing center (Linnan subbasin)where faults are better developed. The sandstones that are coarser in grain size and well-sorted, with low matrix contents have been subjected to stronger dissolution. The influence of the depositional environment on physical properties of reservoirs is manifested by the development degree of primary porosity and its controls on such diagenesis as dissolution and cementation.

       

    /

    返回文章
    返回