Abstract: Elemental capture spectroscopy(ECS) is a new well-logging technique with the extensive applied foreground. The paper takes Shengli oil-field with the viscous oil reservoir in Wangzhuang for example, introduces the principle and method of ECS, analyzes the relation between of the stratum chemical element and ECS, and discusses the applications of ECS data on the geology and petroleum engineering, in order to provide a new technique and method for completely evaluating the reservoir.