Abstract:

Abstract: Prediction of carbonate reservoirs is challenging all over the world.The reservoir spaces of the Ordovician carbonates in Block 4 of Tahe oilfield are dominated by dissolved vug and fracture systems developed from karstification and tectonic movement.These reservoirs feature in deep burial and high heterogeneity.Fine structural interpretation with 3D seismic data reveals that hydrocarbon accumulation is controlled by vertical and horizontal fault distribution,and the dissolved vugs are well associated with faults.Restoration of the Early Hercynian karst paleogeomorphology on the top of MiddleLower Ordovician in Tahe oilfield indicates that the distribution of the Ordovician buriedhill reservoirs in Block 4 of Tahe oilfield is mainly controlled by the karst paleogeomorphology.The areas favorable for the development of fracturedvuggy reservoirs are delineated.Comprehensive analysis shows that the lowlying areas of the ancient terrain should be avoided in the latter development plan refinement,and parameters for fine reservoir description should be adjusted according to the palaeogeomorphology characteristics.Paleogeomorphology restoration lays a basis for reservoir plan refinement and effective development.This method is helpfull for the study of other similar blocks and the discovery of highly productive Ordovician reservoirs in Tahe oilfield.