崖城13-1气田天然气富集条件及成藏模式

位于琼东南盆地西部的崖城13-1气田是中海石油(中国)有限公司的一个对外合作海上大气田,自1996年投产以来,一直肩负着向香港特别行政区和海南省供气的任务。为提高该气田的天然气采收率、满足下游用户不断增长的用气需求量,基于前人的研究成果,结合大量实钻资料,对该气田的天然气富集条件以及成藏模式进行了深入研究。结论认为,崖城13-1气田为基底隆起背景上发育起来的披覆背斜,因顶部遭受削蚀作用而形成的构造—岩性地层复合气藏,气层厚度大、分布稳定、产能高,属高丰度大型气田。该气田同时具有:①有多套烃源岩;②圈闭形成早;③储层厚度大、物性好、产能高;④超压盖层等优越的天然气富集条件。但该气田圈闭范围内,不同断块气、水界面深度不一致,并且构造高部位———南部S3-2含气充满度低,致使该气田的成藏规律复杂化,通过断块间的压力干扰研究,结果证明断层对天然气具有明显的封堵作用。研究成果为该气田后期管理提供了决策依据。

陕北地区石炭—二叠系天然气富集条件的认识

陕北地区天然气勘探成果表明,石炭—二叠系各层段均发现了气层或含气显示,具备了天然气富集成藏的基本地质条件。认为其天然气富集的主要条件是烃源岩的展布范围和生烃能力、有利沉积相砂体、现今低隆起构造部位所形成的岩性圈闭或岩性—构造圈闭、生排烃时间和流体运聚指向区域,这些有利油气地质条件的配置构成了天然气富集区并控制了气藏的分布。

Accumulation of coal-bed gas in the Wangying-Liujia area of the Fuxin basin

The gas enrichment conditions in the Fuxin basin are compared to those of the Powder River basin.The coal bed depth,the gas content,the individual coal bed layer thickness,and the overall structure thickness of the Powder River basin in the U.S.were examined.The main factors affecting gas enrichment were examined.These factors include the coal-forming environment,the gas sources,the geological structure,the presence of magmatic activity,and the local hydrology.The coal-bed gas enrichment area in the Wangying-Liujia block of the Fuxin basin is then discussed by analogy.A hydrodynamic-force/dike-plugging model based on a magma fractured bed is proposed to explain the gas enrichment in this part of the Fuxin basin.High gas production is predicted in areas having similar conditions.This work will aid future coal-bed gas exploration and development.