【摘要】 鄂尔多斯盆地奥陶系马家沟组为重要的含气层系,该文深入研究了靖边潜台南部地区马家沟组碳酸盐岩的成岩作用类型及其成岩条件,其中对储集条件最具影响的为白云石化作用、古岩溶作用和胶结交代作用;根据各成岩作用的特征及其共生序列关系,认为这套碳酸盐岩主要经历了准同生成岩、表生成岩、早成岩和中成岩4个成岩阶段,目前已达中成岩阶段的晚期;在成岩作用及其序列组合研究的基础上,开展了成岩相组合研究,粗略划分出3个成岩相,即表生古岩溶-早期充填胶结成岩相、表生古岩溶-埋藏古岩溶成岩相和埋藏胶结成岩相,其中表生古岩溶-埋藏古岩溶相具有最好的储集性。根据影响各成岩相分布因素的初步研究,确定了重点研究层段成岩相的平面展布,为该区的储层评价及预测提供了依据。更多还原

【Abstract】 Majiagou Formation is an important Ordovician gas-bearing formation in Ordos Basin.The diagenesis types and the petrogenetic conditions of carbonate rocks of Majiagou Formation in southern Jingbian tableland are studied.The result shows that dolomitisation,ancient karstification and cemented metasomatism are dominated factors for the reservoir.According to various diagenesis characteristics and paragenetic sequence relations,it is concluded that this set of carbonate rocks mainly experienced four diagenetic stages:penecontemporaneous diagenetic stage,epidiagenetic stage,early diagenetic stage and anadiagenetic stage,and at present,it reached the later period of anadiagenetic stage.Based on the research of the diagenesis and combinatory sequence,the diagenetic facies is studied,and it is roughly divided into three diagenetic facies,including hypergene ancient karst-early filling cementation diagenetic facies,hypergene ancient karst-buried ancient karst diagenetic facies and buried cementation diagenetic facies.Hypergene ancient karst-buried ancient karst diagenetic facies has the best reservoir quality.Based on the studies on the influencing factors,the plane distribution of the diagenetic facies is definited,which provides foundations for reservoir evaluation and prediction.更多还原