廊固凹陷中西部下第三系天然气藏形成条件及富集规律

FORMATION CONDITIONS AND ACCUMULATION LAWS OF PALEOGENE GAS RESERV OIRS IN WEST-MIDDLE LANGFANG-GU'AN SEG

廊固凹陷是华北油田下第三系产气的主力凹陷 ,是最早向京供气的产气区 ,现在是陕京输气管线向北京供气的应急调峰的重点后备地区。文章主要从构造特征、天然气成因类型、生储盖组合特征、天然气保存条件等方面阐述了廊固凹陷中西部下第三系天然气藏的形成条件及富集规律。重点阐述了中浅层天然气的成因类型及天然气的成藏条件 ,建立了该地区气藏的成藏模式。勘探实践证明 ,该区天然气资源丰富 ,构造、储层、运移与保存配置合理 ,成藏条件优越 ,完全具备形成较大储量规模的气田。尤其是旧州—固安构造带勘探程度较低 ,又有多个有利构造 ,应是比较现实的勘探领域。

Langfang Gu'an Seg is the major seg,where natural gas has been produced from Paleogene,in North China Oil Field,being the gas pr oducing area of earliest supplying natural gas to Beijing,and now it is the key reserve area of emergency peak shaving for supplying gas to Beijing with Shaanxi Beijing gas pipeline.In the paper,the formation conditions and accumulation la ws of paleogene gas reservoirs in West Middle Langfang Gu'an Seg are expounded mainly according to structural features,gas genetic types,source reservoir se al assemblage characteristics and gas preservation conditions,etc.,and the genet ic types and reservoir formation conditions of medium shallow natural gas are e mphatically stated through setting up a gas reservoir formation model for this a rea.It is proved in practice that the reservoir formation conditions in the area are excellent because of abundant gas resources and a fine reasonable combinati on of the reservoir and structural settings with the oil & gas migration and pre servation conditions,therefore this area is fully qualified for forming large s ized gas fields.Especially,the Jiuzhou Gu'an structural belt should be the more realistic exploration territory owing to low exploration degree and existent se veral beneficial structures.