塔中地区良里塔格组碳酸盐岩储层特征及成岩作用

Carbonate reservoir characteristics and diagenesis in the Lianglitage Formation,Tazhong region,Xinjiang

塔中地区良里塔格组发育巨厚的礁滩相碳酸盐岩,为碳酸盐岩储层的形成提供了有利条件。通过对钻井岩心和薄片分析,系统研究了研究区良里塔格组碳酸盐岩的储层岩石学、成岩作用类型和特征,总结了各类成岩作用的识别标志、发育规律及对储集体形成的影响。研究区碳酸盐岩储层的成岩作用包括泥晶化作用、白云石化作用、方解石胶结作用、溶蚀作用、硅化和硅质充填作用,以及压实、压溶作用、破裂作用和自生黄铁矿作用。在此基础上,总结了良里塔格组碳酸盐岩成岩序列及储层孔隙演化规律,认为早期强烈的方解石胶结作用和压实压溶作用降低了储层的孔隙度和渗透率,而溶蚀作用和构造破裂作用对良里塔格组礁滩相碳酸盐岩优质储层的形成具有明显控制作用。

The reef-shoal carbonate rocks are developed with tremendous thickness in the Lianglitage Formation, Tazhong region, Xinjiang. The present paper deals, according to well logs and thin section examination, with the petrology and diagenesis, as well as the criteria for recognization, development and impacts of the diagenesis on the reservoir rocks. Main diagenetic processes include ： micritization ; compaction and pressure solution ; dolomitization; calcite cementation; dissolution; silicification and silicic filling; authigenic pyrite, and fracturing. The early calcite cementation, compaction and pressure solution may reduce the porosity and permeability of the reservoir rocks, whereas the dissolution and structural fracturing may play constructive role in the formation of excellent carbonate reservoirs in the Lianglitage Formation, Tazhong region, Xinjiang.