| The Middle-Lower Ordovician Yingshan 2nd Member carbonate reservoirs are developed in Well ZG-48 area, Tazhong,Tarim Basin. The 2nd Member of Yingshan Formation can be divided into the Upper and the Lower Submembers. According to drilling data, the seismic reflections of different submembers and reservoirs are calibrated. According to seismic amplitude properties, the seismic prediction and evaluation are carried out for the carbonate reservoirs after drilling. The reservoirs are divided into Types I,II and III in decreasing grade. It is shown that the Upper and the Lower Submember reservoirs are about 110m thick and about 260m thick respectively and distribute in the range of downward 0～100m and 110~100m respectively beneath the top surface of Yingshan Formation. The Upper Submember reservoirs develop well along the unconformity surface but Type I reservoirs are less in lower location of the anticline. The Lower Submember reservoirs that are thicker than the Upper ones are close related with faults. It is evaluated that the Types I reservoirs are obviously more in the Lower Submember than in the Upper Submember. Commercial oil flow has been drilled out at the Lower Submember in Well ZG-45, which implies good prospecting potential also in the Lower Submember. |
