Reserves Estimation for Ultra-deep Fault-Controlled Fractured Cavity Carbonate Reservoirs

The interval from the Ordovician Yijianfang Formation to the 2nd member of Yingshan Formation in Fuman Oilfield is a typical fault-controlled carbonate fractured-vuggy reservoir. Its dynamic reserves estimation is a challenge for reservoir engineer. An improper estimation may result in large error and even mistakes in development decision-making. Based on the reservoir and flow characteristics as well as the challenges such as limited static pressure data, undefined development laws and difficult parameter determination in Fuman Oilfield, this paper proposes two methods, i.e. well test analysis and flowing material balance, to estimate the dynamic reserves. The basic principles and application conditions of the two methods are introduced, and verified with examples. The calculation results indicate that the dynamic and static reserves are basically consistent, providing a basis for the formulation of reservoir development strategies.