Lower Permeability Reservoir Description Of The Triassic In The Northern Area Of Shaanxi Province

This research is focused on Yan'an area of ordos basin, with the object of Upper Triassic Yanchan Formation and the core of Chang 6 reservoir(6th part of Yanchan Formation), based on analyzing the reservoir and oil reservoir from deposition, diagenesis, anisotropism, crack, and influence of deep huge fault inside the basin. The formation, distribution and controlling factor of remaining oil are also discussed. This research is tried to find the regulation of oil reservoir and the relationship of that with sediment, structure, reservoir. It will be useful for the research of oil production in northern shaanxi province.The stratum frame of Yanchang formation in Yan'an area is founded with the sequence-stratigraphy, Chang 6 is anatomised in detail. Sediment system is analyzed, mode of lithology and logging curve responding, sedimentary microfacies and evolvement is established.The reservoir rock physics property is analyzed with a lot of methods such as analyzing diagenesis, granularity, general reservoir properties and sensitivity of reservoir, watching core and slice, etc.. The Consolidation and cementation affect storage capability greatly, and the dissolution contribute great to the porosity, the Chipping mineral including mica strengthen anisotropism, complex hole structure, debase storage capability. The whole appraisement is given to the Chang 6 formation.The tracer is used to study the crack of Chang 6 oil-bearing of Yanchang Formation in Chuankou oilfield. The direction of crack is EW strike mainly and NE secondly in this area, and a little in NW and NS. Fractures is identify with gravity anomaly, combining logging and geology data to recognize aim formation. So fractures characteristics of different formation are got. It is a useful method to solve time difficult point of fractures forming. The crack and fracture play a key role in the formation and distribution of oil reservoir. This point is important to low permeability reservoir of northern shaanxi province.The distribution of remaining oil is mainly in edge of sedimentary facies, watering spread degree is a key standard to distinguish existence of remaining oil.With whole, dynamic and compositive thinking, geological exploration and exploitation, technology factors are maximum amalgamation. The reservoir of Upper Triassic Yanchangformation of Yan'an area in ordos basin is researched in detail. The new results are got from the new method and thought.