Passive magnetic ranging for SAGD and relief wells via a linearized trailing window kalman filter
First Claim
1. A method of drilling a well, comprising:
- obtaining a first estimate of a location of the well with respect to a reference well at a selected depth;
obtaining a magnetic measurement at the selected depth using a sensor, wherein the obtained magnetic measurement is related to a residual magnetic charge distribution in the reference well;
determining an expected value of the magnetic measurement at the selected depth from the residual magnetic charge distribution;
obtaining a second estimate of the location of the well using the first estimate of the location, the obtained magnetic measurement, the expected value of the magnetic measurement and a Kalman filter; and
altering a drilling parameter of the well using the second estimate of the location.
1 Assignment
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Accused Products
Abstract
A method of drilling a well is disclosed. A first estimate is obtained of a location of the well with respect to a reference well at a selected depth. A magnetic measurement is obtained at the selected depth using a sensor. The obtained magnetic measurement is related to a residual magnetic charge distribution in the reference well. An expected value of the magnetic measurement at the selected depth is determined from the residual magnetic charge distribution. A second estimate is obtained of the location of the well using the first estimate of the location, the obtained magnetic measurement and the expected value of the magnetic measurement. A drilling parameter of the well is altered using the second estimate of the location.
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Citations
18 Claims
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1. A method of drilling a well, comprising:
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obtaining a first estimate of a location of the well with respect to a reference well at a selected depth; obtaining a magnetic measurement at the selected depth using a sensor, wherein the obtained magnetic measurement is related to a residual magnetic charge distribution in the reference well; determining an expected value of the magnetic measurement at the selected depth from the residual magnetic charge distribution; obtaining a second estimate of the location of the well using the first estimate of the location, the obtained magnetic measurement, the expected value of the magnetic measurement and a Kalman filter; and altering a drilling parameter of the well using the second estimate of the location. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A system for drilling a well proximate a reference well, comprising:
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a drill string configured to drill the well; a sensor disposed on the drill string configured to measure a downhole magnetic field; a processor configured to; obtain a first estimate of a location of the well with respect to a reference well at a selected depth of the sensor, obtain from the sensor a magnetic measurement at the selected depth related to a residual magnetic charge distribution in the reference well, determine an expected value of the magnetic measurement at the selected depth from the residual magnetic charge distribution, obtain a second estimate of the location of the well using the first estimate of the location, the obtained magnetic measurement, the expected value of the magnetic measurement and a Kalman filter, and alter a drilling parameter of the well using the second estimate of the location. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A computer readable medium having stored thereon instructions that when read by at least one processor enable the at least one processor to perform a method of drilling a well, the method comprising:
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obtaining a magnetic measurement from a sensor at a selected depth, wherein the obtained magnetic measurement is related to a residual magnetic charge distribution in the reference well, determining an expected value of the magnetic measurement at the selected depth from the residual magnetic charge distribution, obtaining a second estimate of the location of the well using the first estimate of the location, the obtained magnetic measurement, the expected value of the magnetic measurement and a Kalman filter; and altering a drilling parameter of the well using the second estimate of the location. - View Dependent Claims (16, 17, 18)
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Specification