Abstract: A method of using oriented seismic sensors to delineate the surface of a geologic unit having an anomalous velocity, such as salt dome is disclosed. Seismic sensors having three orthogonal axes of sensitivity are sealed in a housing and are attached to the outside of a tubing means. The tubing means is lowered into a wellbore that penetrates the geologic unit to a known depth, and a liquid such as cement is pumped through the tubing and up the annular space to fixedly attach the sensors to the geologic formation. The orientation of the sensor axes can then be calculated from an observed orientation of the reference directions of the sensor housings. Seismic wavefields are then propagated through the geologic unit and the surrounding earth, and are observed by the sensor axes of sensitivity, and are recorded and transmitted to the top of the tubing.

Abstract: A method and apparatus for detecting the orientation of downhole geophones are provided. A gamma ray source is secured to a casing enclosing a geophone such that the location of the gamma ray source with respect to the orientation of a geophone is known. The geophone is secured to tubing such that the orientation of the geophone with respect to the tubing is known. The tubing, with attached geophone, is secured downhole. A gamma ray logging tool is run the length of the tubing. The orientation of the downhole geophone is determined from the gamma ray log.

Abstract: A non-magnetic apparatus is disclosed for finding the deflection of the vertical. That apparatus has a device for finding an instrument spatial angle between a reference direction and an instrument characterization direction, and a device for finding a deflection spatial angle between the instrument characterization direction and a direction along a plumb line. Preferably, the device for finding the instrument spatial angle uses a system of gyroscopes. Preferably, the device for finding the deflection spatial angle uses a pendulum.

Abstract: A vertical alignment apparatus has a light and a light fixture attached to a cable to be lowered into the cylinder to be aligned. A disk mounted on top of the light fixture and centered about the light fixture and the cable causes the light emitted from the light fixture to form a halo between the disk and the wall of the cylinder. A tripod on top of the cylinder movingly centers the light, light fixture and disk in the cylinder. The method of the invention involves lowering the apparatus into the cylinder. The light fixture is activated to create a halo of light around the disk. The light fixture is then raised up the casing, and the casing is adjusted until the halo has circular consistency.

Abstract: A rotating target contains an appropriately shaped section of photoelectric material which detects the position of a beam of light which is incident on the target. The position of the beam is determined in terms of its distance from the center of rotation of the target and by its angular position relative to the vertical. The vertical direction is simultaneously determined relative to the rotating target using a gravity operated reference.

Abstract: Methods and apparatus for vertical alignment of a borehole rig directly over a drilling site involve use of a camera placed in parallel orientation to the drilling mast or drill string and sighted in on the drill target, then allowed to swing free to the true-plumb position, thereafter bringing the mast back into parallel orientation with the now-plumb camera.