THE FEATURES OF THE CARBONATE RESERVOIR OF QIULITAGE GROUP BETWEEN UPPER CAMBRIAN AND LOWER ORDOVICIAN IN BACHU AREA

The carbonate reservoir of Qiulitage Group between Upper Cambrian and Lower Ordovician is the main reservoir member in this area.It is a suit of local platform sediment.The horizon of the vantage reservoir situated in the member consists of cross bedding of dolomite and limestone and the dolomite member. Because of the influence of sedimentary facies,diagenesis and tectonism, induced porosity,dissolved cavern and fracture are the dominant types of the reservoir space.Especially because of the influence of the action of dissolution and the reconstruct of faults,the carbonate rock of Qiulitage Group had become highclass reservoirs.They are distributed in the south of the Kangtakumu-mazhata structural zone and high yield commercial gas had been achieved in them.