从成岩-蚀变特征探讨塔深1井白云岩储层成因  

Formation of deep dolomite reservoir of Well TS1:Insights from diagenesis and alteration investigations

作　　者：尤东华 王亮[3] 胡文瑄[1] 钱一雄[2] 王小林[1] 陈强路[2] 张军涛[4] 

机构地区：[1]南京大学地球科学与工程学院,江苏南京210023 [2]中国石化石油勘探开发研究院无锡石油地质研究所,江苏无锡214126 [3]中国石化西北油田分公司,新疆乌鲁木齐830011 [4]中国石化石油勘探开发研究院,北京100083

出　　处：《岩石矿物学杂志》2018年第1期34-46,共13页Acta Petrologica et Mineralogica

基　　金：国家重点基础研究发展计划("973"计划)(2012CB214802);国家科技重大专项(2011ZX05005-002);国家自然科学青年基金(41702134);中国石化科技开发部项目(P13069;P16112)~~

摘　　要：塔深1井钻遇的寒武系地层属于中寒武统阿瓦塔格组和上寒武统丘里塔格下亚群。阿瓦塔格组以灰色-深灰色粉晶-细晶藻白云岩为主,丘里塔格下亚群以灰色-浅灰色晶粒结构白云岩与残余亮晶结构白云岩为主。藻白云岩在阴极发光下以明亮的中等强度砖红色-桔黄色为主要特点,具有相对偏重的δ18O值(-6.3‰^-4.5‰,平均为-5.3‰,VPDB)、相对较高的稀土总量以及与正常海相碳酸盐岩相似的稀土配分样式。晶粒白云岩与残余亮晶结构白云岩在阴极发光下以偏暗的中等强度蓝紫色-砖红色为主要特点,具有相对偏轻的δ18O值(-9.2‰^-5.7‰,平均为-7.5‰,VPDB)、相对偏低的稀土总量、Eu正异常与重稀土明显亏损为特点的稀土配分模式。阿瓦塔格组和丘里塔格下亚群白云岩在上述岩石学特征和地球化学特征上的差异表明储层发育的成岩-蚀变过程存在差异。研究认为,埋藏较深的阿瓦塔格组优质储层的形成受多种因素控制,其中准同生期大气淡水作用下石膏结核的溶解及非稳定碳酸盐矿物的溶解奠定了基础,后期成岩改造及流体作用进行了强化,局部遭充填破坏。Cambrian strata of well TS1 are composed of Awatage Formation （middle Cambrian） and the lower Qiulitage Group （upper Cambrian）. A detail investigation of cores and analysis of thin sections shows that Awatage Formation is mainly composed of dark gray to gray algal dolomite （micritic to fine-crystal）, and Qi- ulitage Group is mainly composed of gray to light gray crystalline dolomite and ghost structure dolomite. Algal dolomites are present in moderate strength with brick-red to orange colors as the main features under cathodolu- minescence together with δ18O value from - 6.3‰ to - 4.5‰ （average value is - 5.3‰, VPDB）, and contain a relatively high total rare earth elements （REE） with REE patterns similar to those of normal marine carbonate rocks. Crystalline dolomites and ghost dolomites show purple to red-brick color in dimly moderate strength under cathodolumineseene with lighter δ18O value from -9.2‰ to -5.7‰ （average value is -7.5‰, VPDB）, together with relatively low total rare earth element/positive Eu anomaly and obvious loss of HREE. The difference between Awatage Formation and Lower Qiulitage Group indicates that the diagenesis-alteration process of dolomite reservoirs is different. This study suggests that the high quality reservoir of Awatage Formation in great depth might be controlled by several factors. Among them, dissolution of gypsum nodules and other unstable minerals by meteoric water or sea water in penecontemporaneous period established the foundation, followed by diagenesis-alteration strengthening constructively with fluid action, which even damaged the space by local filling and recrystallization.

关 键 词：成岩-蚀变 塔深1井 白云岩储层 超深层 塔里木盆地 

分 类 号：P618.130.21[天文地球—矿床学] P588.245[天文地球—地质学]