柴达木盆地西部地区第三系湖相藻灰岩油气藏及勘探潜力  

Tertiary Lake Algal Limestone Oil and Gas Reservoirs in Western Part of Qaidam Basin and Exploration Potential

作　　者：陈子炓[1] 寿建峰[1] 王少依[1] 蒙绍兴[1] 

机构地区：[1]中国石油勘探开发研究院杭州地质研究所,浙江省杭州市310023

出　　处：《中国石油勘探》2004年第5期59-66,共8页China Petroleum Exploration

摘　　要：柴达木盆地第三系藻灰岩储层分布较广,是柴达木盆地第三系碳酸盐岩储层中最重要的油气储层。目前柴达木盆地第三系藻灰岩储层主要见于西部地区的跃西、跃东、七个泉、狮子沟、花土沟、尖顶山、南翼山和大风山等地区,层位上从下干柴沟组上段(E3)至上油砂山组(N2)均有分布。E3和N1的藻灰岩主要分布于英雄岭222凹陷以西(西南)地区,N2和N2的藻灰岩主要分布于英雄岭凹陷以东(东北)地区,这与柴达木盆地的湖水进退、12沉积中心的迁移及盆地演化有着密切的关系。柴达木盆地西部地区第三系湖相藻灰岩储层的成因类型主要包括两类滨湖亚相的藻坪灰岩和浅湖亚相的藻丘灰岩。滨湖亚相的藻坪灰岩和浅湖亚相的藻丘灰岩具有完全不同的沉积特征、岩石类型和储层特征。滨湖亚相藻坪灰岩储层的储集空间以次生溶孔和溶缝为主,溶孔和溶缝的形成与大气淡水的淋滤作用有关。浅湖亚相藻丘灰岩储层的储集空间以次生溶孔和溶缝为主,同时也发育原生枝管状钙藻(绿藻门的松藻科)的藻管孔,溶孔和溶缝的形成与晚期沿断裂带大气淡水的溶解作用及有机酸的溶解作用有关。柴达木盆地西部地区第三系是青海油田近期的重点勘探目标区,具有很大的油气勘探潜力。近几年发现的藻灰岩是其中一个值得重视的勘探目标,已知地区的藻灰岩储集性质较优。Distributed in extensive areas, Tertiary algal limestone reservoirs in Qaidam Basin are the most important oil and gas reservoirs in the Tertiary carbonate rock reservoirs in the basin. Currently, Tertiary algal limestone reservoirs found in Qaidam Basin are located mainly in the western part of the basin, such as Yaoxi, Yaodong, Qigequan, Shizigou, Huatugou, Jiandingshan, Nanyishan and Dafengshan. They are distributed from the upper section of Lower Ganchaigou Formation (E3 ) to Upper Youshashan Formation (N2 ). The algal limestone of E3 and N1 is distributed mainly in the west of 2 2 2 Yingxiongling Depression. The algal limestone of N2 and N2 is distributed mainly in the east of Yingxiongling Depression. This is closely related to 1 2 invasion and recession of lake water, migration sedimentary center and basin development in Qaidam Basin. There are mainly two diagenetic types for Tertiary lake algal limestone reservoirs in the western region of Qaidam Basin – algal ?at limestone of shore subfacies and algal dome limestone of shallow lake subfacies. They are completely different from one another in sedimentary characteristics, rock type and reservoir characteristics. The space of algal ?at limestone reservoir of shore subfacies is mainly the secondary dissolved pores and dissolved seams, which are formed in relation to ?ltration of atmospheric fresh water. The space of algal dome limestone reservoirs of shallow lake subfacies is mainly the secondary dissolved pores and dissolved seams, with evolution of original calcareous green algal pipe-shape pores at the same time. The dissolved pores and seams are formed in relation to solution of atmospheric fresh water and solution of organic acid along the fault zone in later periods. Tertiary System in the western region of Qaidam Basin is the key exploration target area of Qinghai Oil

关 键 词：藻灰岩储层 第三系 湖相 勘探潜力 西部地区 柴达木盆地 油气勘探 

分 类 号：P618.130.2[天文地球—矿床学]