Method of Fracture Characterization and Productivity Prediction of 19⁃6 Buried⁃Hill Fractured Reservoirs, Bohai Bay Basin

In Bozhong 19 ‐ 6 gas field, due to the different types of reservoir spaces, strong heterogeneity, and unclear of main controlling factor of productivity of buried‐hill fractured reservoirs, which makes it difficult to predict the productivity. In order to solve this problem, the characteristics of buried‐hill fractured reservoirs are analyzed based on core, logging, geological and other data. Additionally, based on the CT scan experiment, the fractures can be quantitatively characterized and a series of calculation methods of fracture parameters including fracture permeability are formed. As a result, the productivity prediction model for buried-hill fractured reservoirs is established and the problem of productivity prediction of buried‐hill fractured reservoirs is solved. The research results show that the fracture permeability of buried‐hill fractured reservoirs is mainly controlled by the length, width and connectivity of the fractures, and has no obvious relationship with the porosity. Then, the fracture permeability can be calculated from the difference between the total permeability obtained by Stoneley wave inversion and the matrix permeability. The relative errors of matrix permeability and total permeability calculations are respectively 28.50% and 15.56%. Based on the fracture permeability, fracture longitudinal connectivity and effective thickness of buried ‐ hill fractured reservoirs, the productivity prediction model for buried ‐ hill fractured reservoirs can be established in Bozhong 19 ‐ 6 gas field. The accuracy of fracture permeability calculation result determines the reliability of productivity prediction result of buried‐hill fractured reservoirs.