鄂尔多斯盆地下奥陶统碳酸盐岩储层深埋次生孔隙研究

鄂尔多斯盆地下奥陶统碳酸盐岩储层是成岩期白云岩化，表生期古岩溶和后生期深埋溶解作用叠加改造的结果．深理溶解作用既可通过扩大改造光期孔洞缝形成溶蚀扩大孔隙体系，亦可通过溶蚀碳酸盐产生新增孔隙体系，从而大大提高了碳酸盐储层储集条件．根据孔隙结构特征，区内碳酸监岩储层深埋次生孔隙可划分为１７种类型，它们是富含有机酸、ＣＯ２和Ｈ２Ｓ的具有化学侵蚀性的酸性地下成岩流体与碳酸盐之间相互作用的产物．无论在沉积学还是沉积地球化学方面，该类次生孔隙均与其它成因孔隙存在明显异性

A Study of Deep Buried Secondary Pores in Carbonate Rock of Lower Ordovician System in Eerduosi Basin

The deep buried secondary pores are the result of laminating and reforming of dolomization,talaeokast in the epidiagenetic stage and dissolution in the epigenetic stage. Deep burial dissolution can enlarge and reform the pores and fractures formed at the early stage and produce new pore system by dissoluting carbonate, therefore greatly improving the reserving conditions of reservoir beds. According to the pore texture,the deep buried secondary pores of the carbonate rock in the area discussed can be classified into 17 types. They are the result of mutual action of acid diagenetic fluids having rich organic acid,CO2 and H2S which can be chemically corroded with carbonate. Deep buried secondary pores are quite different from those of other genesis either from the point of view of sedimentology or from that of sedimentary geochemistry.