深益气藏形成的主控地质因素

Key factors controlling the formation of deep basin gas

分析了深盆气藏的形成机理及地质特征,研究了形成深盆气藏的基本地质条件及主控因素,预测了我国深盆气勘探前景。结果表明:深盆气藏是一种特殊的天然气藏,具有气水倒置、储集层致密、地层压力异常等地质特征;其形成的基本地质条件为,具备区域性稳定沉降的构造,具有与气源岩紧密接触的致密储集层,以及以生气为主(通常与煤系有关)且生排气高峰期晚的源岩,其中具有生排气高峰期晚的源岩是形成深盆气藏的主要控制地质因素;我国众多沉积盆地具有深盆气成藏的地质条件,其中以中部盆地最为有利,西部盆地次之,东部盆地有利区较少。

By analyzing the formation mechanism of and geological characteristics of deep basin gas, this paper discusses the favorable geological conditions and the main controlling facters needed in deep basin gas formation. This paper forecasts the exploration prospect of deep basin gas in the country. Deep basin gas is a particular gas reservoir, which owns the geological characteristics of diversity of gas and water, that of reservoir and strata pressure. The formation conditions of deep basin gas include stable depressed regional tectonic conditions, resource rocks which mainly produce gas-related to coal layer, and the period of generating and draining gas was later, and tight reservoir strata overlying the source rocks directly. Among the conditions, the source condition, especially its maturation history, plays a key role in deep basin gas formation. There are many sedimentary basins in China with the geological conditions of deep basin gas formation and thus with broad exploring prospect in this field.