Characterization And Prediction Of Karst Reservoir Of The Ordos Basin, The Middle Ordovician Majiagou Group

Guided by the theories of carbonate sedimentology, sequence stratigraphy, reservoir geology, diagenesis and well-logging geology, combinated with macroanalysis and mieroanalysis, geology and well-logging, and by the means of cathode luminescence microscope, scanning electron microscope and isotope, the paper analysis the feature of karst reservoir of Majiagou Formation(MF) and subdivides it into four types which is based on lithobgy: Nodular anhydrite -bearing dolomite, Grain dobmite, porphyritic dobmite and gravity-flow depositing dobrudite. All of them are very heterogeneous . aiming at that the heterogeneity of karst reservoir is controlled by litho-facies, diagenetic facies and paleokarst morphologic, together with the experiences and methods of reservoir characterization(RC) from both home and oversea, the author bring out the combinated method(here is Dietufa) of charaterizating heterogeneous reservoir by using litho-facies, diagenetic facies and paleokarst morphobgic. Through combinated characterization of "Dietufa", the author map out accurately their bounder and distribution of the reservoirs: the type of gravity-flow depositing dolorudite and morphyritic dobmite is distributed in western area from well Bul to Dingtanl, the type of grain dobmite is distributed in central area from well S2 to Chengchuanl and the type of nodular anhydrite -bearing dobmite is distributed in eastern area from Shenmu-Jingbian-Yanan. Also, the author predict three favourable area by the result of RC and reservoir reversbn. The predictbns above are in accordance with the result of RC. It has been turn out that the prediction works by drilling in the area of Yulin last yean The author think that the method of characterization and prediction resulted from Ordos basin is helpful for the study in other basins.