Record low oil prices and a high necessity of hydrocarbons have made operators such as OMV Petrom, having more than 8000 active wells, to try to achieve maximum production from the existing wells. Many of these wells require artificial lift methods as the reservoirs are mature and have been producing for decades. Oil exploitation processes are subject to permanent change in parameters such as decline, reaction to secondary processes, flow blockages, equipment wear and failure. Continuously monitoring well parameters in dynamic conditions will allow continuous control over the operation. Having a large volume of data that can be later analysed is useful in optimizing production: maximum rates with minimum costs. Fluid level measurements are of great importance for a successful field development, as the optimum methods of operation for the producing wells need to be chosen correspondingly. Reliable information about the well and reservoir conditions is required. Nowadays, numerous techniques exist for measuring the fluid level, among which the acoustic method is the simplest and widely used. This paper tries to analyse three different devices used for fluid level monitoring and not only, offering a comparison both technical and economical. The first device is the fully automated MURAG 20 developed by Rohöl-Aufsuchungs Aktiengesellschaft (RAG), second is the Echometer developed by the Echometer Company and third, the Downhole Pressure Gauge (DPG). During the research of these devices, not only the liquid level measurement is important to us, but also other information such as bottom-hole pressure (can be derived from fluid level) or pressure build-up tests, which can offer us critical information about the reservoir.