Location determination using vector measurements
AssigneeHalliburton Energy Services, Inc.
InventorGraham McElhinney
Life of this patent
Estimating the term…
Abstract
A method for locating underground cylindrically symmetrical magnetic sources, particularly boreholes, from magnetic field measurements. The method is based on the shape of magnetic field produced by magnetic materials with cylindrical axes. As the field caused by the magnetic source always points away from or towards its cylindrical axis, lines extended from magnetic field vectors caused by the magnetic source will always pass through the axis. Numerical techniques are used to find the common line to all the extended magnetic field vectors and thus calculate the axis of the magnetic source.
Claims15
A method for determining the direction and position of a subterranean formation structure, the structure having a magnetic field, comprising the steps of:
- measuring a reference magnetic field at a point in said formation distant from said structure;
- measuring a total magnetic field at a point in said formation at a point proximate to said structure;
- determining a component of the total magnetic field attributable to said structure based on said reference magnetic field;
- repeating the steps of measuring the total magnetic field and determining the component attributable to said structure at at one or more additional points proximate to said structure;
- generating a set of extended lines corresponding to extended magnetic field vectors attributable to said structure at each point,
- determining a spatial vector which passes closest to all of said extended lines, said spatial vector corresponding to the axis of said structure.
A method for determining the location and direction of a target well borehole penetrating an earth formation from an adjacent well, comprising the steps of:
- positioning a magnetic field measurement instrument in said adjacent well distant from said target well borehole and measuring a reference magnetic field;
- positioning a magnetic field measurement instrument at a known location in said adjacent well, said position being proximate to said target well borehole;
- measuring a total magnetic field at said location;
- determining a magnetic field component attributable to said target well borehole;
- positioning said instrument at at least one additional known location in said adjacent well;
- repeating the steps of measuring said magnetic field and determining said magnetic field component attributable to said target well for each additional location in said adjacent well;
- generating a magnetic field vector for each location, each of said vectors corresponding to said magnetic field component attributable to said target well borehole;
- and
- determining the location and direction of said target well borehole as a function of said magnetic field vectors.
Dependencies are inferred from the claim text.