Abstract The paper describes the use of the Electric Pilot in the Permian Basin formaking permeability surveys of wells and for the selective acidization ofwells. A general summary of the information obtained from the many permeabilitysurveys run in this area is given, and the possible application of thisinformation to reservoir control problems is discussed. The application of theElectric Pilot on specific wells, involving well completion, acidizing andworkover operations is also included.
Introduction The Electric Pilot is a comparatively new tool in oil-producing areas. From thebeginning, the possibilities of this new service caught the imagination of manyof the oil operators and acidizing engineers. Through the continued and everincreasing use of the pilot during the past year, and the close cooperation ofthe oil operators who have used this service, the efficiency and utility of theElectric Pilot service has been increased to a point where it is now a wellestablished and recognized service.
There are two major uses for the Electric Pilot:permeability survey;
selective acid treatments.
Permeability surveys are made to determine the thickness of the variouspermeable sections at the borehole, the vertical position of these zones at thebore hole, and the relative capacities of the various zones.
Nomenclature Data obtained from the permeability survey are used to calculate threedifferent indexes that pertain to the volume of fluid injected into the variouspermeable zones. A nomenclature for these various indexes has been set up, which correspond with the various productivity indexes, except that they are ameasure of injected fluid rather than produced fluid. The nomenclature anddefinition of the indexes used in connection with a permeability survey by theElectric Pilot are as follows:Capacity.-The volume of water injected into an individual permeable zone, ingallons per minute.
Capacity Index.-The volume of water injected into an individual permeablezone, in gallons per minute per pound per square inch differentialpressure.
Specific Capacity Index.-The volume of water injected into an individualpermeable zone in gallons per minute per pound per square inch differential perfoot of thickness of the zone at the borehole.
Capacity is the most generally used index, and for planning initial acidizingprocedures and most workover jobs it is sufficient.
T.P. 1759