Cased-hole formation evaluation logs are playing a major role in efforts to increase recovery from existing reservoirs.While the logs available today are significant improvements over those of just a few years ago, care must still be exercised for successful applications.Application limitations remain, although some of these are being addressed by ongoing research.Limitations involved in conventional process of logging involves the non-productive time taken for the logging unit to arrive at field, running in of the logging tool into the bore hole and retrieving it after its operation.Electronic casing is a modification over the conventional casing.The necessary tool for logging is incorporated in the casing itself and as the casing is lowered into borehole it carries the tool along with it.Operation of the tool and data interpretation takes place from the surface as per the requirements.The tools will be incorporated at strategic point/depth in the casing based on (1) subsurface conditions at that depth and (2) other operations involved with the casing.(e.g-Perforation) Suitable layer envelops the logging tool so that it is not adversely affected by mechanical/ wellbore conditions or subsurface fluids.Tool can be used for almost all cased hole logs.(CBL-VDL, Gamma ray, Neutron etc.) Advantages: · Tremendous reduction in NPT.· No tripping in/out.· Reduction in cost to an extent.