鄂尔多斯盆地东缘XE气田上古生界致密砂岩储层特征及主控因素

Reservoir Characteristics and Main Controlling Factors of Tight Sand Reservoir in Upper Paleozoic in XE Gas Field in the Eastern Ordos Basin

摘要: 为揭示鄂尔多斯盆地东缘XE气田上古生界致密砂岩储层特征及主控因素，本文利用XE气田45口探井岩心观察、粒度分析、砂岩薄片鉴定、扫描电镜、毛细管压力分析、X衍射等手段，系统研究储层岩石学特征、孔喉结构及成岩演化规律，结果表明：该区储层上、下石盒子组储层以长石岩屑、岩屑长石砂岩为主，太原组储层以石英砂岩为主；主要孔隙类型包括残余原生孔、粒间溶孔、粒内溶孔、晶间孔；孔喉结构以中孔细喉及细孔细喉为主；认为浅水三角洲、障壁海岸潮坪等沉积环境决定了储层的物质组成及结构特征，而后期成岩作用决定了致密砂岩储层物性特征：表现为压实作用、硅质胶结作用、碳酸盐胶结作用及粘土胶结作用使储层物性变差，多期次生溶蚀作用形成各类次生溶孔，改善致密储层储集能力。

Abstract: Aiming at revealing the characteristics and main controlling factors of tight sandstone reservoirs in the Upper Paleozoic in XE gas field in the eastern Ordos Basin, this paper studies the petrological features, grain size analysis, thin section analysis, SEM, capillary pressure analysis, X-ray diffraction of 45 wells. The result shows that the main lithology of reservoir of Shihezi Formation includes feldspar litharenite and lithic arkose. Meanwhile, the main lithology of reservoir of Taiyuan Formation was quartz sandstone. The main pore types include follows: primary intergranular pores, intergranular dissolved pores, intragranular dissolved pores and intercrystalline pores; the material bases of these tight reservoirs in this study area were controlled by sedimentary environment like shallow delta or tidal channel, and the present reservoirs’ quality was determined by diagenesis. The compaction and cementation of silica, carbonate and clay mineral made the reservoir properties poor, and multi-phases dissolution was constructive for reservoir properties.