Abstract: A casing drilling with a removable MWD tool comprising a float shoe for removably positioning the bottom of a MWD tool at and or near the drill bit inside the casing, a stabilizer attached to the top of the MWD tool for centrally positioning the MWD tool inside the casing, and a spear positioned on the stabilizer for attaching to retrieval equipment known in the art and also contemplated that after the well is drilled with casing pipe and ready for the production process, a retrieval operation may be lowered into the well to retrieve the MWD tool by attaching to the spear.

Abstract: The present invention provides for casing drilling with a removable MWD tool comprising a float shoe for removably positioning the bottom of a MWD tool at and or near the drill bit inside the casing, a stabilizer attached to the top of the MWD tool for centrally positioning the MWD tool inside the casing, and a spear positioned on the stabilizer for attaching to retrieval equipment known in the art and also contemplated that after the well is drilled with casing pipe and ready for the production process, a retrieval operation may be lowered into the well to retrieve the MWD tool by attaching to the spear.

Abstract: A method and apparatus used to transmit information to the surface from a subsurface location during the process of drilling a bore hole is described. A novel pressure pulse generator or “pulser” is coupled to a sensor package, a controller and a battery power source all of which reside inside a short section of drill pipe close to the bit at the bottom of the bore hole being drilled. The assembled apparatus or “MWD Tool” can be commanded from the surface to make a measurement of desired parameters and transmit this information to the surface by encoding data in pressure pulses generated by a pulser valve that includes a stator and a rotor which may be open and closed to create pressure pulses.

Abstract: A method and apparatus used to transmit information to the surface from a subsurface location during the process of drilling a borehole is described. A novel pressure pulse generator or “pulser” is coupled to a sensor package, a controller and a battery power source all of which reside inside a short section of drill pipe close to the bit at the bottom of the bore hole being drilled. The assembled apparatus or “MWD Tool” can be commanded from the surface to make a measurement of desired parameters and transmit this information to the surface by encoding data in pressure pulses generated by a pulser valve that includes a stator and a rotor which may be open and closed to create pressure pulses.

Abstract: A method and apparatus used to transmit information to the surface from a subsurface location during the process of drilling a bore hole is described. A novel pressure pulse generator or “pulser” is coupled to a sensor package, a controller and a battery power source all of which reside inside a short section of drill pipe close to the bit at the bottom of the bore hole being drilled. The assembled apparatus or “MWD Tool” can be commanded from the surface to make a measurement of desired parameters and transmit this information to the surface by encoding data in pressure pulses generated by a pulser valve that includes a stator and a rotor which may be open and closed to create pressure pulses.