鄂尔多斯盆地西缘前陆盆地中生界成岩作用及特征研究

The Cheng Yan effect and characteristics of Mesozoic in foreland basin on the western margin in Ordos basin

鄂尔多斯西缘前陆盆地中生界储层砂岩成岩作用主要受前陆盆地构造演化的影响,不同构造区带砂岩储层的成岩环境存在一定的差别。研究发现,冲断带近物源区由于杂基和软矿物含量高,压实作用表现较为强烈,砂岩物性较差;但斜坡带远离物源区压实程度较弱,原生粒间孔隙发育。坳陷带比冲断带、斜坡带含有更高含量的富铁方解石,很难遭受后期溶蚀改造,所以坳陷带中铁方解石含量较高的地区储层物性也比较差,其机理可能与黏土矿物转化和长石类矿物发生溶蚀有关。

Ordos West foreland basin of Mesozoic sandstone reservoir diagenesis is mainly affected by a tectonic evolution of foreland basin effect,different tectonic zone sandstone reservoir rock environment into existence certain difference.Study finds,thrust belts near source area due to a heterozygous base and soft mineral content is high,the compaction performance is strong,reservoir physical property is poor;but the slope away from the source region of the degree of compaction is weaker,primary intergranular pores.Depression belt than thrust belt,slope belt containing higher content of iron rich calcite,difficult to suffer later dissolution,so depression belt in calcite content high area reservoir physical properties are relatively poor,its mechanism may be related to clay mineral transformation and related to the dissolution of feldspars occur.