Abstract: A method of determining the stuck point in a bore hole is provided. The method employs a device, such as an inductor or coil, for writing magnetic marks into the bore hole casing. The device is incorporated into a retrieval tool so that when a decision is taken to back off from the bore hole and recover any down hole equipment, the magnetic marks can be written on the casing of the bore hole as the retrieval tool is lowered into place. As the retrieval tool is raised in the bore hole, lifting the down hole equipment towards the surface, the magnetic marks are read using a three dimensional magnetic field sensor disposed either in the fishing tool or in the down hole apparatus itself.

Abstract: A method and apparatus for measuring the properties such as permeability of the rock surrounding a borehole in which a directional seismic or sonic signal is generated downhole and propagated into the surrounding formation to generate an electrokinetic signal and the focus of the seismic signal is moved in three dimensions in the surrounding rock by physically moving the source or by having two seismic sources which generate oscillating seismic signals at different frequencies and the focus of the seismic signal is varied by wave interference or wave interaction.