羌塘盆地中央隆起带南侧隆额尼—昂达尔错布曲组古油藏白云岩特征及成因机制  

The characteristics of Longeni-Angdaercuo paleo-oil dolomite in southern part of the central uplift zone of Qiangtang Basin and its forming mechanism

作　　者：刘建清[1] 杨平[1] 陈文彬[1] 陈文西[1] 付休根[1] 

机构地区：[1]成都地质矿产研究所沉积与能源地质研究室,四川成都610082

出　　处：《地学前缘》2010年第1期311-321,共11页Earth Science Frontiers

基　　金：国家油气专项资助项目(XQ2004-06)

摘　　要：以系统的剖面测制及室内综合研究为基础,系统总结了隆额尼—昂达而错古油藏白云岩的矿物学、晶体学、岩石组构、沉积相、碳和氧同位素及流体包裹体等特征,在该区白云岩中发现了完整的交代鲕粒结构。该区白云岩的典型组构为交代残余结构、雾心亮边结构、等厚环边胶结及世代生长结构,白云岩化集中在台地边缘浅滩、潮坪及台地边缘藻丘礁;白云石晶体有序度总体较高,白云岩δ13C和δ18O值较伴生灰岩偏高,白云岩形成时盐度低于正常海水盐度,温度t高于地表平均温度;白云岩中包裹体含量少而小,均一温度均从白云岩中后期充填方解石脉中获取,其均一温度的两个区间与该区两次大的构造运动及油气生成、运聚过程吻合,白云岩形成于油气注入之前。各种特征均反映出该区白云岩为混合水交代成因,研究丰富了对该古油藏白云岩特征及白云岩成因机制的认识。Based on the field survey,we have conducted a series of research on the Longeni-Angdaercuo paleo-oil dolomite in southern part of Qiangtang Basin central uplift zone,including its mineral and crystal characteristics,lithological composition,sedimentary facies,fluid inclusion,carbon and oxygen isotope. The microstructures of dolomite consist of four types：remnant ooid structure,fogged center and clear margin structure,ring structure and generation growth texture. The dolomitization mainly took place in plateau border shallow water belt,tidal-flat and plateau border algal reef. The degree of ordering of dolomite is generally higher. The value of δ^13C and δ^18O is higher than that of the concomitant calcite; the calculated salinity of fluid in dolomite at the time of its formation is higher than that of the sea water; and the temperature in dolomitization area deduced by the isotopic value is higher than that of the earth surface. The fluid inclusions are few and small in dolomite,mainly obtained from calcite vein; there are two homogenization temperature intervals that correspond to the two tectonism and oil migrations. The dolomitization occurred before the oil migration. All of the information mentioned above suggests that the dolomite in this area should be the result of mixed water replacement of calcite.

关 键 词：白云岩 混合水交代作用 羌塘盆地 

分 类 号：TE122.33[石油与天然气工程—油气勘探]