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Title: Wellbore inertial directional surveying system

Abstract

A wellbore inertial directional surveying system for providing a complete directional survey of an oil or gas well borehole to determine the displacement in all three directions of the borehole path relative to the well head at the surface. The information generated by the present invention is especially useful when numerous wells are drilled to different geographical targets from a single off-shore platform. Accurate knowledge of the path of the borehole allows proper well spacing and provides assurance that target formations are reached. The tool is lowered down into a borehole on the electrical cable. A computer positioned on the surface communicates with the tool via the cable. The tool contains a sensor block which is supported on a single gimbal, the rotation axis of which is aligned with the cylinder axis of the tool and, correspondingly, the borehole. The gyroscope measurement of the sensor block rotation is used in a null-seeking servo loop which essentially prevents rotation of the sensor block aboutthe gimbal axis. Angular rates of the sensor block about axes which are perpendicular to the gimbal axis are measured by gyroscopes in a manner similar to a strapped-down arrangement. Three accelerometers provide acceleration information as the toolmore » is lowered within the borehole. The uphole computer derives position information based upon acceleration information and anular rate information. Kalman estimation techniques are used to compensate for system errors.« less

Inventors:
 [1];  [1];  [1];  [1]
  1. (Albuquerque, NM)
Publication Date:
Research Org.:
AT & T CORP
OSTI Identifier:
867684
Patent Number(s):
US 4987684
Assignee:
United States of America as represented by United States (Washington, DC) SNL
DOE Contract Number:
AC04-76DP00789
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
wellbore; inertial; directional; surveying; providing; complete; survey; oil; gas; borehole; determine; displacement; directions; path; relative; head; surface; information; generated; especially; useful; numerous; drilled; geographical; targets; single; off-shore; platform; accurate; knowledge; allows; proper; spacing; provides; assurance; target; formations; reached; tool; lowered; electrical; cable; computer; positioned; communicates; via; contains; sensor; block; supported; gimbal; rotation; axis; aligned; cylinder; correspondingly; gyroscope; measurement; null-seeking; servo; loop; essentially; prevents; aboutthe; angular; rates; axes; perpendicular; measured; gyroscopes; manner; similar; strapped-down; arrangement; accelerometers; provide; acceleration; uphole; derives; position; based; anular; rate; kalman; estimation; techniques; compensate; errors; sensor block; position information; especially useful; rotation axis; electrical cable; rate information; manner similar; path relative; target formation; wellbore inertial; inertial directional; directional surveying; /33/

Citation Formats

Andreas, Ronald D., Heck, G. Michael, Kohler, Stewart M., and Watts, Alfred C. Wellbore inertial directional surveying system. United States: N. p., 1991. Web.
Andreas, Ronald D., Heck, G. Michael, Kohler, Stewart M., & Watts, Alfred C. Wellbore inertial directional surveying system. United States.
Andreas, Ronald D., Heck, G. Michael, Kohler, Stewart M., and Watts, Alfred C. Tue . "Wellbore inertial directional surveying system". United States. doi:. https://www.osti.gov/servlets/purl/867684.
@article{osti_867684,
title = {Wellbore inertial directional surveying system},
author = {Andreas, Ronald D. and Heck, G. Michael and Kohler, Stewart M. and Watts, Alfred C.},
abstractNote = {A wellbore inertial directional surveying system for providing a complete directional survey of an oil or gas well borehole to determine the displacement in all three directions of the borehole path relative to the well head at the surface. The information generated by the present invention is especially useful when numerous wells are drilled to different geographical targets from a single off-shore platform. Accurate knowledge of the path of the borehole allows proper well spacing and provides assurance that target formations are reached. The tool is lowered down into a borehole on the electrical cable. A computer positioned on the surface communicates with the tool via the cable. The tool contains a sensor block which is supported on a single gimbal, the rotation axis of which is aligned with the cylinder axis of the tool and, correspondingly, the borehole. The gyroscope measurement of the sensor block rotation is used in a null-seeking servo loop which essentially prevents rotation of the sensor block aboutthe gimbal axis. Angular rates of the sensor block about axes which are perpendicular to the gimbal axis are measured by gyroscopes in a manner similar to a strapped-down arrangement. Three accelerometers provide acceleration information as the tool is lowered within the borehole. The uphole computer derives position information based upon acceleration information and anular rate information. Kalman estimation techniques are used to compensate for system errors.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Jan 01 00:00:00 EST 1991},
month = {Tue Jan 01 00:00:00 EST 1991}
}

Patent:

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  • This patent describes a wellbore inertial directional surveying system for providing a complete directional survey of an oil or gas well borehole to determine the displacement in all three directions of the borehole path relative to the well head at the surface. The information generated by the present invention is especially useful when numerous wells are drilled to different geographical targets from a single off-shore platform. Accurate knowledge of the path of the borehole allows proper well spacing and provides assurance that target formations are reached. The tool is lowered down into a borehole on the electrical cable. A computermore » positioned on the surface communicates with the tool via the cable. The tool contains a sensor block which is supported on a single gimbal, the rotation axis of which is aligned with the cylinder axis of the tool and, correspondingly, the borehole. The gyroscope measurement of the sensor block rotation is used in a null-seeking servo loop which essentially prevents rotation of the sensor block about the gimbal axis. Angular rates of the sensor block about axes which are perpendicular to the gimbal axis are measured by gyroscopes in a manner similar to a strapped-down arrangement. Three accelerometers provide acceleration information as the tool is lowered within the borehole. The uphole computer derives position information based upon acceleration information and annular rate information. Kalman estimation techniques are used to compensate for system errors.« less
  • A wellbore inertial directional surveying system for providing a complete directional survey of an oil or gas well borehole to determine the displacement in all three directions of the borehole path relative to the well head at the surface. The information generated by the present invention is especially useful when numerous wells are drilled to different geographical targets from a single offshore platform. Accurate knowledge of the path of the borehole allows proper well spacing and provides assurance that target formations are reached. The tool is lowered down into a borehole on an electrical cable. A computer positioned on themore » surface communicates with the tool via the cable. The tool contains a sensor block which is supported on a single gimbal, the rotation axis of which is aligned with the cylinder axis of the tool and, correspondingly, the borehole. The gyroscope measurement of the sensor block rotation is used in a null-seeking servo loop which essentially prevents rotation of the sensor block about the gimbal axis. Angular rates of the sensor block about axes which are perpendicular to te gimbal axis are measured by gyroscopes in a manner similar to a strapped-down arrangement. Three accelerometers provide acceleration information as the tool is lowered within the borehole. The uphole computer derives position information based upon acceleration information and angular rate information. Kalman estimation techniques are used to compensate for system errors. 25 figures.« less
  • A Wellbore Inertial Navigation System (WINS) was developed and tested. Developed for directional surveying of geothermal, oil, and gas wells, the system uses gyros and accelerometers to obtain survey errors of less than 10 ft (approx. 3 m) in a 10,000-ft (approx. 300-m) well. The tool, which communicates with a computer at the surface, is 4 in. (approx. 10 cm) in diameter and 20 ft (approx. 6.1 m) long. The concept and hardware is based on a system developed by Sandia for flight vehicles.
  • This patent describes a directional drilling apparatus for deflecting a drill bit to drill an offset borehole from the central axial path of a main wellbore of vertical, horizontal, or slanted orientation. It comprises a tool body; inflatable packer means for sealing the main wellbore below the first passageway; means in the first passageway for activating the packer so that it will inflate; the tool body having a second passageway that forms an acute angle with the first passageway; and an entry portion having means for routing the drill bit into the second passageway. This patent also describes a methodmore » of drilling one or more offset wellbores from a first main wellbore. It comprises drilling the initial main wellbore; placing a first, larger drill string in the initial wellbore that has a tool body with first and second passageways therein; orienting the radial position of the second passageway with respect to the initial, main wellbore using a steering tool; placing a second, smaller drill string in the main wellbore and inside the first drill string; diverting the second drill string to the second passageway at a position upstream of first passageway; tracking the second passageway with the second drill string during drilling of an offset wellbore that forms an angle with the first borehole.« less
  • There is an increasing need for higher accuracy in wellbore directional and positional surveying than is currently available using conventional techniques. Among the factors contributing to this need are closed interspacing of wells particularly from offshore platforms, deeper and more highly deviated wells, smaller target formations and the requirement for rapid drilling of relief wells in the case of blowouts. The application of inertial navigation system (INS) of suitable size and cost for this type of application is not inherently accurate enough to offer significant improvements in well-surveying accuracy. Techniques to improve accuracy are, in general, based on the factmore » that the dynamics associated with the propagation of the navigator errors are very well known. Inertial systems are routinely aided using external data from a number of sources. Such aiding may take the form of an external position or velocity measurement which is compared to the position or velocity indicated by the navigator. Kalman filter theory provides a convenient formulation for generation of a minimum variance estimate of the state vector of a linear system. The theory may be extended to the nonlinear case through the use of linearization about a state trajectory. This approach is currently seeing wide use in aiding of inertial navigation systems. The approach proposed here would use the Kalman filter formulation for estimation of the INS errors and updating of the navigator. This formulation also provides a structure for estimation of various instrument parameters which should improve system performance.« less