南堡凹陷高南地区东营组储层成岩作用及孔隙演化研究

Diagenesis and pore evolution of Dongying Formation in Gaonan Aera,Nanbu Sag

根据钻井取心分析测试、岩石薄片和扫描电镜观察等手段,对南堡凹陷高南地区东营组成岩作用和次生孔隙发育特征进行研究,并在此基础上划分了成岩阶段。研究结果表明,东营组碎屑岩地层经历了强烈的压实作用和胶结作用、复杂的交代作用和多期次的溶蚀作用,原生孔隙大部分被破坏,主要以次生孔隙为主,长石的溶蚀是储层中次生孔隙形成的主要原因。从早成岩B期到中成岩A1期,有机质成熟过程、粘土矿物转化等造成的酸性地层水介质,使东营组碎屑岩储层在纵向上主要发育3个次生孔隙发育带。粘土矿物的结晶、石英次生加大作用及碳酸盐胶结物的沉淀对孔隙度的降低起到了关键性作用。

Based on the measurements of drilling,coring,microscopic and microscanning processes diagenesis and secondary pore development of Dongying Formation in Gaonan aera are researched,and recognized some diagenesis stages.The results indicat that strong compaction,cementation,complex metasomatism and dissolution,most primary pores are experienced in the clastic rock strata of Dongying Formation,the pores are mainly secondary and the dissolution of feldspar produces most pore space.From early diagenesis B stage to middle diagenesis A1 stage,the acid stratum liquid caused by the organic matter maturation and clay mineral transformation develope three secondary pores zones in the clastic reservoir of Dongying Formation vertically.The crystallization of clay minerals,quartz secondary enlargement and sedimentation of carbonate sealant play a critical role of porosity reduction.