南襄盆地泌阳凹陷溶孔溶洞型白云岩储层特征与分布规律

Characteristics and Distribution of Dissolved Porous and Caved Dolomitic Reservoirs in the Biyang Sag of the Naxiang Basin

南襄盆地泌阳凹陷安棚地区核桃园组三段上部—核桃园组二段广泛发育盐湖相白云岩夹天然碱沉积,溶孔溶洞型储层主要发育于含碱白云岩中,溶洞为团块状或层状天然碱溶蚀形成,溶孔主要为星散状天然碱溶蚀形成,少量为泥质白云岩中的粘土级钠长石溶蚀成因。溶孔溶洞型白云岩储层在纵向上分布于盆地由砂泥岩相→白云质泥岩-泥质白云岩过渡相→白云岩相→含碱白云岩相→天然碱相演化序列的含碱白云岩相中,横向上与天然碱相邻。层位上主要集中在核桃园组二段的第3亚段,其次是核桃园组三段上部和核桃园组二段第2亚段,平面上分布于云2井、云3井和泌100井等地区。

Dolostones with natron are widely deposited from member Eh2 to the upper sub-member Eh3 in the Anpeng area of the Biyang sag in the Nanxiang basin. Dissolved porous and caved reservoirs mainly occur in dolostones with natron. Caves were formed from lumpy natron dissolution and dissolved pores from the scattered natron dissolution. Part of the dissolution pores were from clay-scale albitite dissolution. Vertically, dissolved porous and caved dolostone reservoirs are distributed in natronic dolostone, evolving from sandstone , mudstone to natron, and the relevant geological unit is member Eh23. Horizontally, these reservoirs are adjacent to the natron beds, and the relevant area is around wells Yun 2,Yun 3 and Bi 100 etc.