柴达木盆地西南区古近系及新近系砂岩储层  

Sandstone reservoirs of the Paleogene and Neogene in southwestern Qaidam Basin

作　　者：马达德[1] 王少依[2] 寿建峰[2] 陈子炓[2] 秦玉娟[2] 唐光明[3] 

机构地区：[1]中国石油大学(北京),北京102249 [2]中国石油勘探开发研究院杭州地质研究所,浙江杭州310023 [3]中国石油青海油田公司勘探开发研究院,甘肃敦煌736202

出　　处：《古地理学报》2005年第4期519-528,共10页Journal of Palaeogeography：Chinese Edition

基　　金：国家重点基础研究发展规划项目(编号:G1999043303)资助

摘　　要：根据40余口钻井的岩石学资料，较系统地描述了柴达木盆地西南区古近系及新近系的砂岩储层特征及其主要影响因素。(1)砂岩储层的岩石(矿)成分在时空上呈现规律性的变化。在研究区东南和西北两侧，砂岩成分成熟度和结构成熟度均比中部地区明显偏低；从古近系到新近系，砂岩的成分成熟度和结构成熟度均逐渐降低。砂岩储层岩石学的这种变化明显地影响到其储集性能，造成本区东南和西北两侧砂岩储层性能比中部地区差。(2)砂岩储层的孔隙类型以原生孔隙为主。前人多数认为本区古近系及新近系砂岩储层的孔隙类型以次生孔隙为主，尤其是下干柴沟组，主要发育次生孔隙。作者认为本区古近系及新近系砂岩储层以原生孔隙为主，其次为胶结物溶孔和碎屑颗粒溶孔，次生孔隙仅在有限程度上改善了砂岩的储集性能。(3)压实作用的差异性是影响储集性能的主要因素，其次为胶结作用。压实作用的大小受埋藏深度和岩性的影响，也与储层的埋藏方式有关。砂岩储层中的胶结物以方解石和硬石膏为主，也见少量方沸石。不同层段砂岩中的方解石胶结物含量为4.0％～16.0％，局部地区硬石膏胶结物含量可达11.5％～28.0％，成为影响储集性能的主要因素。Based on the petrologic data of about 40 wells, the characteristics and the main controlling factors of the Paleogene and Neogene sandstone reservoirs in southwestern Qaidam Basin are systematically described. （1）The composition of sandstone reservoirs varies regularly in space and in time. The compositional maturity and textural maturity of sandstones are obviously lower in the southeastern and northwestern parts of the study area than in the central part, and gradually decline from the Paleogene to the Neogene. The variation of sandstone reservoir petrological features obviously affects its reservoir quality, which leads to the results that the quality of sandstone reservoir is lower in the southeastern and northwestern parts of the study area than in the central part. （2） Primary porosity is the main pore type in sandstone reservoir. Previous researchers have different viewpoints on the pore types of sandstone reservoir. Most of them believe that the main type of pore is secondary pore, especially in the Xiaganchaigou Formation, the secondary pores were widely developed. The sandstone reservoirs of the Paleogene and Neogene were mainly developed with primary pores, while the cement dissolution pore and rock debris dissolution pore were also developed. The secondary pore only improved the quality of sandstone reservoirs slightly. （3） The dominant factor resulting in the great change of reservoir quality is the difference of compaction, and then the cementation. The compaction is affected by burial depth and lithology, and also is related to the way that the reservoir was buried. The cements in the sandstone reservoir are dominated by calcite and anhydrite with subordinate analcite. The content of calcite cements varies from 4.0% to 16.0% in different strata, locally the content of anhydrite cement may be up to 11.5 % -28.0 %, and thus becomes the primary factor affecting the reservoir quality.

关 键 词：柴达木盆地 古近系及新近系 砂岩储层 储集性能 成岩作用 

分 类 号：P618.130.2[天文地球—矿床学] P534.62[天文地球—地质学]