Abstract: A method for determining the precise position of the drill bit, in three dimensions, in the earth during a drilling operation, with a minimum of effort and interruption to the drilling process. It provides placing a motion sensor on the drilling apparatus and a plurality of vibration sensors or geophones, positioned in a two-dimension array on the surface of the earth, above the expected position of the drill bit. To make a measurement from which can be determined the position of the bit, the drill stem is raised a selected distance and suddenly released, so that it will fall in the borehole, and the bit will strike the bottom of the hole. This impact will cause an elastic wave to be generated at the bottom of the borehole. The elastic wave will be transmitted through the earth and will be detected by the geophones. The sensor provides information from which can be determined the time when the bit strikes the bottom of the drill hole. This determines the initiation time of the elastic wave.

Abstract: A method for determining the precise position of the drill bit on the bottom of a long drill string in a deep borehole in the earth during a drilling operation, with a minimum of effort and interruption of the drilling process. It provides placing a plurality of geophones in an array on the surface of the earth above the expected position of the drill bit. A frangible object is inserted into the drill pipe near the surface whereby the mud stream will carry it down through the pipe to the bit where it will close off the mud flow through the bit. The mud pressure above the object will increase and when it reaches a high enough value the object will shatter and there will be a sudden flow of mud through the openings of the bit in the form of a shock wave, which will generate a seismic wave in the earth at the location of the bit. The expanding seismic wave will be detected by the geophones at the surface from which the times of arrival at the various geophones can be determined.

Abstract: Method and apparatus for logging the position of a deep borehole filled with liquid in the earth, comprising a long, continuous small diameter pipe adapted to be reeled up on a drum mounted on a vehicle, and means to insert the end of the pipe into the mouth of a borehole and to lower it to any desired depth in the earth. A plurality of geophones are positioned on the surface of the earth in the vicinity of the borehole with conventional amplifying and recording means connected thereto. Means are provided on the vehicle for compressing a liquid or gas, and injecting it into the pipe. On the bottom end of the pipe is a chamber in which this pressurized fluid can be stored. Fast acting valve means are provided which on signal can suddenly open and permit the stored fluid in the chamber to explosively expand into the liquid in the annulus of the borehole.