It is increasingly important to improve field productivity in today's competitive market. One way to achieve this, is to add new wells which are expensive and time consuming. The other alternative is to identify bypassed hydrocarbons, track changes in saturations and detect movement of reservoir fluid contacts from existing well bores already in place. It is considerably more cost effective and often more environmentally friendly to explore for those hidden hydrocarbons in old wells rather than drill new wells. As the field matures, there is a need to reevaluate the formation in older reservoirs and to focus the development strategy and approach on bypassed oil pockets and depletion levels in producing intervals. The ability to acquire essential logging data behind casing adds a new dimension to cased hole formation evaluation for locating and evaluating potential hydrocarbon zones in a mature field as in Magid field. A basic petrophysical evaluation was performed incorporating the data recorded behind casing by applying {Cased Hole Formation Resistivity Logging (CHFRL)} in each of these wells. Based on the analysis of cased hole formation evaluation results. The un-depleted intervals were commercially exploited adding reserve to the asset. Keywards: Hydrocarbon zones, Majid Field, Sirte Basin, Libya, CHFRL