靖边气田的成藏特点表现为:(1)气源为双向供给,二源混合;(2)储层空间以膏溶孔隙、白云石化孔隙为主,以裂缝为辅;(3)以地层和岩性圈闭为主,古构造决定了充注方向;(4)气藏流体具非均一性和负压特征;(5)地层水为有水不见水层,分隔"卧底"保存.探讨了形成这些特征的机理.同时提出促使成藏的主要地质因素是四项"合理搭配":(1)封闭海域与宽阔坪台搭配造就有利生储相带;(2)剥蚀脊与侵蚀沟搭配形成层状溶蚀水流;(3)切割与充填、溶蚀与充填搭配形成地层、岩性遮挡;(4)孔隙空间与裂隙网络搭配使得储产兼得.

This research indicates that gas reservoirs in Jingbian Gasfield, Ordos, are characteristic of: (1) Gas is supplied by mixed gas sources from two directions; (2) Reservoir space are dominated by anhydrite-dissolved and dolomitized pores and subordinated by fractures; (3) Stratigraphic and lithogic traps are common and paleostuctures control the direction of hydrocarbon migration and emplacement; (4) Fluids in gas reservoirs are of heterogencity and negative pressure feature; (5) Formation water are compartmentally preserved without water beds. The mechanism resulting in these characteristics are discussed. The main geological factors leading to gas accumulation are owing to four "fitting match" conditions: (1) The match of enclosed sea with wide flats brings up good source-reservoir facies belt; (2) The match of erosion ridges with erosion grooves builds up layered dissolved currents; (3) The match of cutting with filling, and dissolution with filling, forms stratigraphic traps and lithologic traps; (4) The match of pore space with fissures nets gets to both gas reserves and output.