【摘要】 钻井资料显示莺歌海盆地现今存在超压,纵向上由浅至深可划分为常压带、过渡带和超压带。利用测井声波时差和地震速度资料,按等效深度法计算了莺歌海盆地大量排气期(1.9 Ma)和现今超压值,并恢复了单井超压的演化。结果表明,地层超压平面上是以乐东区为中心向北向东递减的,临高隆起带和莺东斜坡带大部分为常压,单井上超压演化是逐渐增大的。这一结果与不同地区地质历史上沉降中心和沉积环境密切相关。莺歌海盆地超压的存在使天然气在剩余压力的作用下垂向运移。天然气藏均分布在乐东和东方地区黄流组项底压差大、莺歌海组盖层超压封闭能力强的地区。靠近底辟区、且同时满足上述2个条件的储层更有利于天然气成藏。更多还原

【Abstract】 Drilling data show that there is overpressure in the Yinggehai basin now.Vertically,from the shallow to the deep,the pressure zones can be divided into normal pressure zone,transitional zone and overpressure zone.Data of both acoustic travel time of well logging and seismic velocity have been used to determine the distribution of overpressure on the period of the most gas discharge(1.9 Ma ago)and at present with the method of compaction equilibrium,and to restore the pressure evolution of the wells in the Yinggehai basin.The result shows that,laterally,Ledong area has the biggest overpressure which decreases both from south to north and from west to east,but in Lingao uplift and Yinggehai eastern slope,most places are in normal pressure zone.In each well,the overpressure increases with time.This result is closely related to the centre of subsidence and different zone’ s sedimentary environment.Because overpressure exists in the Yinggehai basin,gas migrates vertically under the influence of overpressure.Natural gas pools are distributed in Ledong area and Dongfang area where Huangliu Formation’s roofs and floors have large pressure differences and Yinggehai Formation’s cap rocks have big sealing ability of overpressure.The reservoirs which satisfy the above two conditions and near diapirs arc favorable for the accumulation of natural gas.更多还原