It has been well-established that Device-to-device (D2D) communication underlying cellular networks can improve network radio resource efficiency and provide higher transmission data rates to devices in proximity. In this work, we propose a cooperative system model. Three relay selection schemes are compared under such model. The Distance-based Relay Selection considers only distance for optimal relay selection, Social-Based Relay Selection scheme choose relays only depends on social relation, and Hybrid Relay Selection scheme includes both distance and social relation factors. Simulation results show that the hybrid relay-selection schemes can greatly improve the performance of D2D cooperative communications.