A method is presented for evaluation of formation invasion and formation permeability by conducting a series of formation resistivity loggings in the operation of a measurement while drilling (MWD) logging system.
In an MWD measurement system, the speed of rotation of a downhole turbine is measured by the interaction of a triaxial magnetometer in a sensor package and a permanent magnet attached to the turbine shaft. The triaxial magnetometer may be part of an existing MWD system for measuring borehole directi ...
An extending arm is incorporated into a formation evaluation MWD collar or sub for extending outwardly from the tool and maintaining direct and continuous contact with the borehole wall (e.g., formation). In accordance with this invention, a method is presented for intermittently deploying the exten ...
A method is presented, for use in borehole drilling, for correcting errors in azimuth determination resulting from variations in the earth's magnetic field to which a measuring instrument is exposed. The method distinguishes between variations in the earth's magnetic field caused by the drillstring ...
A method is presented for measuring the azimuth angle of a borehole being drilled, the data for determining the azimuth angle being obtained while the drillstring is rotating.
A method and apparatus for establishing a remote communications link from the rig floor to the downhole MWD system is presented. In accordance with the present invention, the state of a physical condition downhole is changed in a predetermined timed sequence. This state change is controlled on the s ...
A method and apparatus is presented for measuring the azimuth angle of a borehole being drilled, the data for determining the azimuth angle being obtained while the drillstring is rotating.
A preferred embodiment of a system for rotating and guiding a drill bit in an underground bore includes a drilling motor and a drive shaft coupled to drilling motor so that drill bit can be rotated by the drilling motor. The system further includes a guidance module having an actuating arm movable b ...
A preferred embodiment of a system for rotating and guiding a drill bit in an underground bore includes a drilling motor and a drive shaft coupled to drilling motor so that drill bit can be rotated by the drilling motor. The system further includes a guidance module having an actuating arm movable b ...
Preferred methods and systems generate a control input based on a periodically-varying characteristic associated with the rotation of a drill string. The periodically varying characteristic can be correlated with the magnetic tool face and gravity tool face of a rotating component of the drill strin ...
