Research On Depositional System And Forcasting Perspective Plays Of The Pre-jurassic In Wuding Area In Ordos Basin

The Ordos basin is a large Mesozoic intracontinental basin superimposed on the Paleozoic North China craton which contains abundant oil and gas resource. Wuding area lies in the west of Northern Shanbei Slope, Ordos Basin. Yan-10 and yan-9 layers are the important reservoirs in Yan'an formation. Many progresses have been achieved in these area, but there are some problems remained, which include the confusion as to the stratigraphic division, depositinal facies and palaeogeomorphic features of the Pre-jurassic Jurassic which cause many problems in later exploration.On the basis of the theory of and sequence stratigraphy, combined with outcrop profiles, well data and logging data, the paper sets up Jurassic high resolution sequence stratigraphic framework and analysis provenance in this area by rock-mineral characteristics; Controlled by Jurassic high resolution sequence stratigraphic framework, it studies the time-space evolution of sedimentary facies comboinded with core facies and log facies and rebuilds the paleogeomorphology of the pre-Jurassic based on formation thickness from erosion bed to upper and lower marker beds.It indicated that upper members of Yan'an formation are deposited in deltaic and fluvial sediment systems controlled by Jurassic high resolution sequence stratigraphic framework; We identify colliculus palaeogeomorphology cell in Wangpanshan and Tiebiancheng areas; Synthetizing trap type and accumulation model etc, we forecast many favorable zones.