英南2井气藏致密砂岩盖层的形成  

The formation of the dense sandstone cap in the Well Yingnan 2, Tarim Basin

作　　者：余和中[1] 张丽霞 韩守华[3] 朱国华[3] 斯春松[3] 

机构地区：[1]中国地质大学能源系 [2]新疆阜康准东采油厂研究所 [3]中国石油勘探开发研究院杭州分院

出　　处：《石油勘探与开发》2004年第5期133-135,共3页Petroleum Exploration and Development

摘　　要：钻井取心和录井资料显示,塔里木盆地英南2井侏罗系气藏中的主力气层之上均为砂岩,缺少泥岩盖层.通过对铸体薄片的观察,结合电性、物性、压汞、扫描电镜和黏土矿物X衍射分析资料,发现英南2井主力气层之上有两段致密砂岩层能够作为气藏的有效盖层.致密砂岩层内富含高度分散的泥杂基(含量达6.6%～13.8%),呈网状和包膜状分布于砂粒表面和粒间,其强烈的水锁效应能使气体渗透率降低80%以上,在含水条件下,气体渗透率可由0.47～0.69mD降至小于0.1mD或趋于不渗透状态,这是这类致密砂岩成为有效盖层的主要原因.The data of the cores and the well-logs show the rocks above the main gas layers are all sandstone instead of argillite in the Well Yingnan 2. Based on the casting thin section observing and researches on the electricity, property of the cores, mercury-injection, SEM and clay mineral X-ray diffraction data, it is clearly discovered that two sets of dense sandstone in the Well Yingnan 2 could be the effective caps of the gas layers. The sandstone contains rich asunder argillaceous matrix (6. 6%-13.8%), and it deposits in the surfaces of the grains and intergrains in net-like and envelope-like way. The strong water-lock effect could make permeability to decrease by more than 80%. Under the condition of water existence, the air permeability could decrease from 0. 47-0. 69 mD to lower than 0.1 mD, which is the key cause of the dense sandstone developing into an effective cap rock.

关 键 词：塔里木盆地 气藏 致密砂岩层 泥杂基 盖层 水锁效应 

分 类 号：TE122.25[石油与天然气工程—油气勘探]