川西拗陷上三叠统须家河组的天然气成藏模式和盖层封闭机理

从沉积、成岩作用和岩层受挤压三个方面阐明了须家河组致密储层的成因。在对烃演化、孔隙演化、沉积埋藏史和构造变动进行分析的基础上,提出了川西拗陷须家河组天然气的成藏模式,即压实排水、油气生成和运移、油气富集及成藏三个阶段。通过测定岩石的捕集漏失,将盖层岩石分为三级,用以衡量盖层的封闭能力。经过对比,认为该区是以更致密的砂岩封闭致密砂岩为特征的局部封闭。还用计算机对储盖层的分布进行了描述。

A GENETIC MODEL OF THE GAS POOLS OF XUJIAHE FORMATION, UPPER TRIASSIC IN THE WEST SICHUAN DEPRESSION OF SICHUAN BASIN

This article explains the formation of dense reservoir of Xujiahe Formation from three as-pects: the deposition, the diagenesis and the compression of beds. Based on the analysis of evolutionalhistory of hydrocarbons and pores, the buried history of sediments, and the tectonic deformation a mod-el of the formation of gas pools of Xujiahe Formation of Upper Triassic in the West Sichuan Depressionis advanced. It includs three stages: the compaction and water withdrawal, the origin and migration ofoil and gas, and the formation and accumlation of oil and gas pools. On the basis of measurement of thetrapped losses of the reservoir rocks, the cap beds are divided into three classes to measure the evolutionof sealed capacity of the these beds. Through comparison, in this area it is believed to be the local sealedtrap within the dense sandstones which are closed by the denser sandstones. The distribution of the capbeds and reservoir beds is also described with computer modeling.