Abstract: A method for determining a rate of change of longitudinal direction of a subterranean borehole includes positioning a downhole tool in a borehole, the tool including first and second longitudinally spaced surveying devices disposed thereon. The method further includes causing the surveying devices to measure longitudinal directions of the borehole at first and second longitudinal positions and processing the longitudinal directions of the borehole to determine the rate of change of longitudinal direction of the borehole between the first and second positions. The method may further include processing the measured rate of change of longitudinal direction of the borehole and a predetermined rate of change of longitudinal direction to control the direction of drilling of the subterranean borehole. Exemplary embodiments of this invention tend to minimize the need for communication between a drilling operator and the bottom hole assembly, thereby advantageously preserving downhole communication bandwidth.

Abstract: A method for determining a rate of change of longitudinal direction of a subterranean borehole includes positioning a downhole tool in a borehole, the tool including first and second longitudinally spaced surveying devices disposed thereon. The method further includes causing the surveying devices to measure longitudinal directions of the borehole at first and second longitudinal positions and processing the longitudinal directions of the borehole to determine the rate of change of longitudinal direction of the borehole between the first and second positions. The method may further include processing the measured rate of change of longitudinal direction of the borehole and a predetermined rate of change of longitudinal direction to control the direction of drilling of the subterranean borehole. Exemplary embodiments of this invention tend to minimize the need for communication between a drilling operator and the bottom hole assembly, thereby advantageously preserving downhole communication bandwidth.

Abstract: A method for communicating with a downhole device is provided. The method includes predefining an encoding language including codes understandable to the device, the codes represented in the language as predefined value combinations of drill string rotation variables such as rotation rate or duration. The method further includes rotating a drill string at first and second rates and measuring the rotation rates downhole. The first measured rotation rate is processed downhole in combination with the second measured rotation rate to acquire a code in the language at the downhole device. Embodiments of the invention are useful, for example, for transmitting commands from the surface to a downhole device such as a directional drilling tool. Exemplary embodiments of this invention advantageously provide for quick and accurate communication with a downhole device without substantially interrupting the drilling process.

Abstract: A method for determining a rate of change of longitudinal direction of a subterranean borehole is provided. The method includes positioning a downhole tool in a borehole, the tool including first and second surveying devices disposed thereon. The method further includes causing the surveying devices to measure a longitudinal direction of the borehole at first and second longitudinal positions and processing the longitudinal directions of the borehole at the first and second positions to determine the rate of change of longitudinal direction of the borehole between the first and second positions. The method may further include processing the measured rate of change of longitudinal direction of the borehole and a predetermined rate of change of longitudinal direction to control the direction of drilling of the subterranean borehole.

Abstract: A method for determining a rate of change of longitudinal direction of a subterranean borehole is provided. The method includes positioning a downhole tool in a borehole, the tool including first and second surveying devices disposed thereon. The method further includes causing the surveying devices to measure a longitudinal direction of the borehole at first and second longitudinal positions and processing the longitudinal directions of the borehole at the first and second positions to determine the rate of change of longitudinal direction of the borehole between the first and second positions. The method may further include processing the measured rate of change of longitudinal direction of the borehole and a predetermined rate of change of longitudinal direction to control the direction of drilling of the subterranean borehole.

Abstract: A method for communicating with a downhole device is provided. The method includes predefining an encoding language including codes understandable to the device, the codes represented in the language as predefined value combinations of drill string rotation variables such as rotation rate or duration. The method further includes rotating a drill string at first and second rates and measuring the rotation rates downhole. The first measured rotation rate is processed downhole in combination with the second measured rotation rate to acquire a code in the language at the downhole device. Embodiments of the invention are useful, for example, for transmitting commands from the surface to a downhole device such as a directional drilling tool. Exemplary embodiments of this invention advantageously provide for quick and accurate communication with a downhole device without substantially interrupting the drilling process.

Abstract: A gamma ray spectral tool is provided that can be used in slick line systems. The tool includes a battery, a controller, and a memory. In operation, the tool compresses data from the spectral detector for storage in the memory, allowing for long runs without the memory overflowing. Further, a controller latches the self-adjusting stabilization feature of the spectral detector when gamma ray intensity exceeds a predetermined threshold, preventing erroneous "stabilization" by the stabilization feature of the spectral detector.