Predominant Characteristics of Formation and Distribution for Lithologic Petroleum Reservoir in Erlian Basin,Inner Mongolia

The exploration in Erlian Basin in recent years shows that the lithologic reservoir has more predominant conditions in formation and distribution.The predominance in formation includes 4 aspects: ① lithologic traps have more forming periods and times,and it is helpful to entrap oil;② lithologic reservoirs can be formed with only primary migration and short distance secondary migration;③ lithologic reservoirs can be charged with oil earlier than structure reservoirs;④ lithologic reservoirs have more advantaged sealing conditions.Lithologic reservoirs experience little destruction in the later structural activities: uplift and fault activities can destroy(lithologic) reservoirs little than structure reservoirs.The scope of distribution of lithologic reservoirs is more(abroad:) ① lithologic reservoirs can distribute not only in steep slope structure belt,but also in gentle slope structure belt and sag belt;② lithologic reservoirs can enrich not only in low system tracts(LST),but also in high system tracts(HST);③ lithologic reservoirs can distribute in all types of geopressures.So it is concluded that the lithologic reservoirs in Erlian Basin have predominant conditions in their formation and distribution.