Evolution of abnormally low pressure and its implications for the hydrocarbon system in the southeast uplift zone of Songliao basin, China
Evolution of abnormally low pressure and its implications for the hydrocarbon system in the southeast uplift zone of Songliao basin, China
复制标题
DOI：
10.1306/080602870099
复制
发表时间：
2003
期刊：
影响因子：
3.5
通讯作者：
Xinong Xie;J. Jiao;Zhonghua Tang;C. Zheng
中科院分区：
文献类型：
--
作者：
Xinong Xie;J. Jiao;Zhonghua Tang;C. Zheng
中国东北松辽盆地东南隆起地区存在负压地层。盆地石屋坳陷下白垩统地层深度在1540～3000m之间，地层显着负压，约为静水压力的50%～80%。油气勘探表明，凹陷内油气分布具有异常特点：凹陷中部为气藏，隆起边缘为油藏；一些气藏位于150-450 m的非常浅的深度。探讨了异常压力的形成机制和油气分布特征。数值模型表明，该盆地在其历史的大部分时间里都以超压为主，只有在最近的地质时期才变得低压。早期的超压似乎对于目前低压的发生至关重要。负压的起源主要是由于抬升和侵蚀以及地温梯度的减小造成的。我们的研究还表明，地层压力的演化不仅影响流体流动，还影响油气运聚和油气分布。因此，负压的发展是研究区域碳氢化合物栖息地的一个主要因素。
Underpressured formations are present in the southeast uplift of the Songliao basin, northeast China. At depths between 1540 and 3000 m, the Lower Cretaceous strata in the Shiwu depression of the basin are significantly underpressured at about 50-80% of hydrostatic pressure. Exploration for oil and gas indicates that the hydrocarbon distribution in the depression has unusual characteristics: gas pools occur in the central part of the depression, whereas oil pools occur at the marginal uplift; some gas reservoirs are located at a very shallow depth of 150-450 m. We investigate the mechanism of the abnormal pressures and the characteristics of the hydrocarbon distribution. Numerical modeling indicates that the basin was dominated by overpressure through much of its history and became underpressured only in recent geological time. The earlier overpressurization appears to be essential for the occurrence of the underpressure at the present. The origin of underpressure results primarily from uplift and erosion, as well as reduction of geothermal gradients. Our study also shows that evolution of formation pressure affects not only fluid flow but also hydrocarbon migration and accumulation and gas and oil distribution. The development of underpressure is, therefore, a major factor responsible for habitats of hydrocarbons in the study area.