IFP, Elf-Aquitaine horizontal well logging

The successful drilling of three wells with horizontal drain holes, by Elf-Aquitaine and Institut Francais du Petrole (IFP), created an unusual logging problem. Logging tools are conventionally run on wireline, falling to the bottom of the well by the action of gravity. In a horizontal drain hole, gravity only forces the tool to the lower wall of the hole, and cannot be used to move the tool along the length of the horizontal (or nearly so) drain hole in the reservoir. IFP and Elf-Aquitaine have a new technique called Simphor (Systeme d' Instrumentation et de Mesures en Puits Horizontaux) which uses drill pipe to push the tool to bottom, while logs are recorded as each stand of drill pipe is run in the hole. Logs also can be recorded as the drill pipe is retrieved.