Abstract: A wellbore survey tool and methods for estimating a direction of highest gamma ray intensity of a gamma ray distribution are provided. The tool includes a body having a center axis. The body is configured to be placed within a wellbore. The tool further includes a plurality of gamma ray detectors within the body. Each detector of the plurality of gamma ray detectors has a direction of maximum gamma ray sensitivity with the direction having a non-zero component perpendicular to the center axis. The non-zero components of the plurality of gamma ray detectors are spaced circumferentially about the center axis.

Abstract: A wellbore survey tool and methods for estimating a direction of highest gamma ray intensity of a gamma ray distribution are provided. The tool includes a body having a center axis. The body is configured to be placed within a wellbore. The tool further includes a plurality of gamma ray detectors within the body. Each detector of the plurality of gamma ray detectors has a direction of maximum gamma ray sensitivity with the direction having a non-zero component perpendicular to the center axis. The non-zero components of the plurality of gamma ray detectors are spaced circumferentially about the center axis.

Abstract: A wellbore survey tool and methods for estimating a direction of highest gamma ray intensity of a gamma ray distribution are provided. The tool includes a body having a center axis. The body is configured to be placed within a wellbore. The tool further includes a plurality of gamma ray detectors within the body. Each detector of the plurality of gamma ray detectors has a direction of maximum gamma ray sensitivity with the direction having a non-zero component perpendicular to the center axis. The non-zero components of the plurality of gamma ray detectors are spaced circumferentially about the center axis.

Abstract: A wellbore survey tool and methods for estimating a direction of highest gamma ray intensity of a gamma ray distribution are provided. The tool includes a body having a center axis. The body is configured to be placed within a wellbore. The tool further includes a plurality of gamma ray detectors within the body. Each detector of the plurality of gamma ray detectors has a direction of maximum gamma ray sensitivity with the direction having a non-zero component perpendicular to the center axis. The non-zero components of the plurality of gamma ray detectors are spaced circumferentially about the center axis.

Abstract: In certain embodiments, a steerable drilling tool is provided including a rotatable shaft extending through a housing where the shaft and the housing are separated by at least one bearing or two sets of bearings, the shaft having a first portion terminating at a first end of the shaft and a second portion terminating at a second end of the shaft. The steerable drilling tool may further include a drill bit structure operatively coupled to the first portion and a steering subsystem comprising a pair of bearings operatively coupled to the first portion. The steering subsystem may be configured to angulate the shaft by exerting force substantially through the pair of bearings. In certain embodiments, the first portion is between the first end and about one-third of the length of the shaft from the first end towards the second end.

Abstract: In certain embodiments, a steerable drilling tool is provided including a rotatable shaft extending through a housing where the shaft and the housing are separated by at least one bearing or two sets of bearings, the shaft having a first portion terminating at a first end of the shaft and a second portion terminating at a second end of the shaft. The steerable drilling tool may further include a drill bit structure operatively coupled to the first portion and a steering subsystem comprising a pair of bearings operatively coupled to the first portion. The steering subsystem may be configured to angulate the shaft by exerting force substantially through the pair of bearings. In certain embodiments, the first portion is between the first end and about one-third of the length of the shaft from the first end towards the second end.