It is believed that naturally fractured reservoirs (NFR) contain more than 50% of the worlds total oil and gas reserves. Therefore, E&P companies are directing enormous interests towards NFR, especially within the last forty years. The main target of this work is to study different recovery processes of fractured reservoirs using a single matrix block model of homogeneous and isotropic matrix properties. In a single matrix block model, both continua, i.e. the matrix and the fractures, are discretized and represented within the model by simulation cells. This enables a detailed investigation of matrix-fracture interaction and makes the use of transfer function superfluous. The block sizes were defined by the shape factor formulation proposed by Kazemi et al. For various porosities, permeabilities and wettabilities, different recovery mechanisms like expansion drive, water and gas displacement were investigated. The thesis consists of theoretical and practical parts. In theoretical part, general information is given about NFR, fracture types, fracture detection and fractured reservoir characterization methods. The practical part consists of water imbibition investigations of water-wet reservoir rocks. Based on the results, an attempt is made to create an algebraic correlation of the ultimate recovery factor.