Apparatus and methods to find a position in an underground formation

Patent metadata

Field	Value
Publication number	US-2015369951-A1
Application number	US-201214649720-A
Country	US
Kind code	A1
Filing date	Dec 31, 2012
Priority date	Dec 31, 2012
Publication date	Dec 24, 2015
Grant date	—

Abstract

Various embodiments include apparatus and methods related to finding a position in an underground formation. Apparatus and methods can include receiving signals from a receiver in an underground formation in response to signals generated from transmitting sources, each of the transmitting sources located at a known position; and processing the received signals, based on the signals generated from the transmitting sources, to determine the position of the receiver. A number of techniques can be applied to processing the received signal. Additional apparatus, systems, and methods are disclosed.

First claim

1 . A method comprising:
receiving signals from a receiver in an underground formation in response to signals generated from three or more transmitting sources, each of the three or more transmitting sources located at a known position, at least one transmitting source of the three or more transmitting sources separated from and mounted on a structure different from at least one other transmitting source of the three or more transmitting sources; and processing the received signals, using an inversion process based on the signals generated from the three or more transmitting sources, to determine the position of the receiver.

2 . The method of claim 1 , wherein the processing of the signals to determine the position of the receiver is conducted downhole.

3 . The method of claim 1 , wherein the method includes controlling the three or more transmitting sources including a transmitting source that has a current-carrying wire of a closed loop of a circuit, the current-carrying wire being at a known position, the current-carrying wire arranged along a straight-line path such that signals received at the receiver from the closed loop are negligible from portions of the closed loop that follow a path different from the straight-line path.

4 . The method of claim 1 , wherein the method includes
controlling the three or more transmitting sources including a transmitting source that has a number of current-carrying wires forming a closed loop of a circuit, each of the number of current-carrying wires being at a known position and arranged along a straight-line path such that signals received at the receiver from the closed loop are negligible from portions of the closed loop that follow a path different from the straight-line paths; and processing the signals based on a model of the number of current-carrying wires and their corresponding straight-line paths.

5 . The method of claim 1 , wherein the method includes controlling the three or more transmitting sources including at least three dipole transmitters.

6 . The method of claim 1 , wherein the method includes controlling the three or more transmitting sources including a source generating large distribution of current aboveground or near ground that generate electromagnetic fields below ground, the electromagnetic fields measurable at the receiver, the large distribution of current being at a known position.

7 . The method of claim 1 , wherein the three or more transmitting sources include one or more transmitting sources located aboveground.

8 . The method of claim 1 , wherein the method includes generating at least one signal of the generated signals from a transmitting source aboveground or near ground, the signal having a low frequency to penetrate deeply underground such that the signal is measurable in an underground volume extending from a hundred feet to thousands feet in depth and from a hundred feet to thousands of feet across the depth.

9 . The method of claim 1 , wherein the method includes operating the three or more transmitting sources sequentially such that only one of the three or more transmitting sources is on at one time period.

10 . The method of claim 1 , wherein the three or more transmitting sources include a transmitter in a well.

11 . The method of claim 1 , wherein the three or more transmitting sources include no more than two transmitters in a plane that contains the receiver.

12 . The method of claim 1 , wherein the method includes operating each of the transmitting sources at a frequency less than about 50 Hz.

13 . The method of claim 1 , wherein using the inversion process includes:
generating values of a signal expected at the receiver from each of the transmitting sources; generating a difference between the signal expected and the signal received from the receiver, when the difference is less than a threshold, selecting values of coordinates for the receiver, as the position of the receiver, that generated the signal expected at the receiver for which the difference is less than the threshold; and when the difference is greater than the threshold, generating new values of a signal expected at the receiver and determine if a difference between the new values and the signal received from the receiver is less than the threshold.

14 . The method of claim 13 , wherein generating values of the signal expected at the receiver includes using an estimate of the position of the receiver with a forward model.

15 . The method of claim 13 , wherein generating values of the signal expected at the receiver includes using an estimate of the position of the receiver with a lookup table.

16 . The method of claim 1 , wherein using the inversion process includes:
generating an estimate of the position of the receiver, the receiver taken as a first receiver; generating an estimate of each position of one or more other receivers, each of the one or more other receivers having a known position with respect to the first receiver, generating values of signals expected at the first receiver and at the one or more other receivers from each of the transmitting sources; generating a difference between the values of the signals expected and a combination of the signal received at the first receiver and signals received at the one or more other receivers; when the difference is less than a threshold, selecting values of coordinates of the first receiver, as the position of the first receiver, that generated the signals expected at the first receiver for which the difference is less than the threshold; and when the difference is greater than the threshold, generating a new estimate of the position of the first receiver, if the inversion process is within a maximum iteration.

17 . The method of claim 1 , wherein using the inversion process includes:
generating sets of values of a signal expected at the receiver, each set generated from a different estimate of the position of the receiver; generating differences between the values of the signal expected and the signal received from the receiver for each set; and selecting the estimate that minimizes error in the difference between the values of the signal expected and the signal received from the receiver.

18 . The method of claim 17 , wherein generating the sets of values of signals expected at the receiver includes using a forward model with each of the estimates.

19 .- 33 . (canceled)

34 . A machine-readable storage device having instructions stored thereon, which, when performed by a machine, cause the machine to perform operations to:
receive signals from a receiver in an underground formation in response to signals generated from three or more transmitting sources, each of the three or more transmitting sources located at a known position, at least one transmitting source of the three or more transmitting sources separated from and mounted on a structure different from at least one other transmitting source of the three or more transmitting sources; and process the received signals, using an inversion process based on the signals generated from the three or more transmitting sources, to determine the position of the receiver.

35 . The machine-readable storage device of claim 34 , wherein the instructions include instructions to control the three or more transmitting sources including a transmitting source that has a current-carrying wire of a closed loop of a circuit, the current-carrying wire being at a known position, the current-carrying wire arrange

Assignees

• Halliburton Energy Services Inc

Inventors

• San Martin Luis Emilio
• Guner Baris
• Donderici Burkay

Classifications

• E21B47/024 Primary

  of devices in the borehole (determining slope or direction of the borehole E21B47/022) · CPC title

• E21B47/09

  Locating or determining the position of objects in boreholes or wells {, e.g. the position of an extending arm}; Identifying the free or blocked portions of pipes · CPC title

• G01V3/30

  operating with electromagnetic waves · CPC title

• G01V3/26 Primary

  operating with magnetic or electric fields produced or modified either by the surrounding earth formation or by the detecting device (with electromagnetic waves G01V3/30) · CPC title

• G01V3/38 Primary

  Processing data, e.g. for analysis, for interpretation, for correction · CPC title