大庆长垣以东地区深源气盖层研究

RESEARCH ON CAP ROCK OF DEEP SOURCE GAS IN EAST AREA OF CHANGYUAN,DAQING

大庆长垣以东地区封盖深源气的区域盖层是下白垩统青山口组巨厚泥岩层，下白垩统泉头组及其以下地层中的泥岩层为局部盖层。青山口组益层封闭水溶气和游离气能力强于泉头组及其以下盖层，盖层封闭扩散气能力随着盖层埋藏深度的增加而增加。泉头组及其以下的盖层形成时间较早．但因分布面积小，后期断裂破坏严重，不能有效地封盖和保存早期排运的深源气；青山口组盖层形成时间晚，在该盖层形成以前，上侏罗统排运的天然气绝大部分得不到保存，青山口组盖层形成之后，深源气几乎毫无损失地被封益于青山口组盖层之下。

he mudstone with great thickness of Qingshankou formation of Cretaceous Series is a regional cap rock of sealing deep source Sas in east area of Changyuan. Daqing. The mudstboe of Quantou formation of Lower Cretaceous Series and the under one of it are partial cap rock. The Qingshan formation cap rock's capability of sealing aqueous gas and free gas is stronger than those of Quantou formation and the cap rock under it. The capability of sealing diffuse gss increases along with the burial depth of cap rock. The forming time of Quantou formation and the cap rock under it is earlier but unavailable fot sealing and preserving the:deep source gas exhausted in early period as less distributive area and serious rupture damages in later period. The cap rock of Qingshankou formation are lately formed. Most of the gas exhausted from Upper Jurassic Series could not be presered before forming them. But after that,deep source gas is perfectly sealed under the cap rock.