莺歌海盆地地温-地压系统特征及其对天然气成藏的意义

Relationship between Accumulation of Natural Gas and Geotemperature-Geopressure System in Yinggehai Basin

莺歌海盆地是一个典型的高温高压新生代伸展—转换型盆地,其烃源岩热演化、天然气运聚成藏都与温压场特征密切相关。尝试运用整体、耦合的观点和地温—地压系统理论,在详细分析莺歌海盆地地温场和地压场分布特征的基础上认为,莺歌海盆地中央泥底辟带发育高压型复式地温—地压系统,而莺东斜坡带则发育单一型地温—地压系统。结合中央泥底辟带和莺东斜坡带天然气藏的分布特征,分析了不同地温—地压系统模式对天然气运聚的影响和控制作用,探讨了在不同地温—地压系统模式下天然气成藏的意义,指出了中央泥底辟带和莺东斜坡带不同的地温—地压系统模式对应的天然气运聚模式。

Yinggehai Basin is a youthful Cenozoic sedimentary basin with extension and transform. There are relationships between geotemperature-geopressure system, source rock thermal evolution and migration accumulation of natural gas. Based on the analysis of the distribution of the geopressure field and the geotemperature field, there are two types of geotemperature-geopressure systems in the basin; composite geoperature-geossure system of high pressure in the central sag and singleness of temperature-geopressure system in the Yingdong slope.The controlling function of different geotemperature-geopressure systems on migration and accumulation of natural gas were analyzed. The vertical migration and accumulation of natural gas are under the control of conducting system and composite temperature-pressure system of high pressure, and the singleness of geotemperature-geopressure system and feebleness of vertical hydrodynamic force are the main reasons for lateral migration of the gas. There are important relationships between the migration of natural gas and the geotemperature-geopressure systems in the Yinggehai basin.