【作者】 张玥；

【导师】 何明友；

【作者基本信息】 成都理工大学 ， 地球化学， 2010， 硕士

【摘要】 本文主要研究了柴达木盆地北缘西段第三系的成岩作用。以沉积学和地球化学理论为指导,利用多种测试分析手段,对该区的成岩作用进行了深入分析和探讨。这对该区下一步的油气勘探部署和降低勘探成本具有很重要的意义。利用野外露头资料、钻井岩芯资料、薄片鉴定、X-射线衍射、扫描电镜等分析测试手段进行了储层岩石学及成岩作用的研究。研究结果表明,目标区内岩石具有较低的成分成熟度和长石含量、以及较高的岩屑含量,以岩屑长石砂岩及长石岩屑砂岩为主,主要为长石岩屑砂岩,其次为岩屑长石砂岩。而且第三系储层砂岩的结构成熟度偏高,尤其具有很低的杂基含量和较好的碎屑分选性,从第三系的下部地层段到上部地层段,砂岩的成分成熟度是显著降低的,而结构成熟度总体上却是增加的。成岩作用类型主要有压实作用、胶结作用、泥质充填作用、溶蚀作用和交代作用,其中,压实作用与胶结作用是影响砂岩物性的两个最为重要的成岩因素。而胶结作用和碳酸盐岩的沉淀作用是工区内储层物性好坏的主要原因。本文我们取得以下认识:(1)压实作用是研究区储层砂岩最为重要的破坏性成岩作用,造成的储集空间的损失占储集空间全部损失量的58%,而胶结作用是影响柴盆北缘西段第三系储层物性好坏的另一重要因素,在很大程度上控制了储层储集物性在平面上和纵向上的分布;(2)柴达木盆地北缘西段第三系砂岩中碳酸盐胶结物数量上是第一多的自生矿物,它的存在对研究区第三系砂岩的储层物性有着至关重要的影响;(3)柴达木盆地第三系以来,气候为干旱-半干旱乃至干旱,从而造成研究区第三系地层富含伊利石和伊/蒙混层,绿泥石和高岭石相对不发育,而蒙脱石和绿/蒙混层则相对少见;(4)虽然储层砂岩胶结物中的粘土矿物绿泥石和高岭石,对孔隙的发育是有利的,但是研究区第三系地层中绿泥石和高岭石的含量较少,因此,它们对本区储层物性的影响是相当有限的;(5)虽然自生石英胶结作用对储层的影响是致命的,但是由于本区第三系储层砂岩中自生石英含量相当低,因此,由自生石英所引起的胶结作用对研究区物性的影响不大。更多还原

【Abstract】 This article eyes on the diagenesis research of Tertiary Reservoirs on the west part of the Northern margin in the Qaidam basin, under the guidance of sedimentology and geochemistry theories, basing on the date analysis of outcrop drilling, core,slice, x-ray diffraction ,SEM and ,reservoir Lithological, the author researched the diagenesis and reservoir characteristics deeply, which is very important for the further exploration and reducance the cost of exploration../ The rock in where is certain area is low component maturity and low content of feldspar, high content of lithic, and the main type is lithic arkoses and feldspar litharenite, Furthermore the sandrock in where the area is high textural mature, especially much low content of matrix and good sorting of matrix. There is evident reducance of sandrock textural mature from the down stratum to up layer of teriary. There is main type of Diagoenesis, including mainly compaction, cementation, Silty filling ,dissolution and Metasomatism which first two was most primary of Diagenesis element and quality control element to sandrock on the reservoir .Features and diagenesis is stuied in detail. In this area, and componential lmaturities is lower and the Lithological types are mostly lithic arkoses and feldspar litharenite. The first important is feldsparlitharenite, the less important is lithic arkoses.In this area, the textural maturity is higher; the matrix is lower and the sorting fragmental. From down to top textural maturity is increase of the whole. Diagoenesis types: mainly compaction, cementation, Silty filling ,dissolution and Metasomatism. The former two functions are the main reasons of reservoir quality. We have got the result:1) It is most important element for researching reservoir sandstone sandrock that compaction to destroy the diagoenes,the room took 58% out of all lost space of reservoir room,further the aonther most important element for contorl the quality of the reservoir room of tertiary on the west part of the Northern margin of the Qaidam basin, it control the layot of the pertity on plane and portrait ’s certain area.2) The amount of cementation of carbonate on tertiary on the west part of the Northern margin of Qaidam basin is marjor partation, it is the control element of pertity on the certain research area.3) Since this area the major climate is dry or dry-sim dry, it is reason the high quatity of ilite and low quatity of chlorite and kaolinite on the certain geology lay, also the limit interfet element to the pertity of area.4) Cause the low quatity of chloriteand and kaolinite on the certain geology lay, the hole has been control in certain range on the research area, which is top urgent to the hole.5) Samilar condition on the low quatity of quartz of cementation, cause the quatity the quartz was able to contorl the pertity on the tertiary reservoirs on the west part of the Northern margin on the certain research area.更多还原