Two-dimensional imaging with multi-stage processing

Patent metadata

Field	Value
Publication number	US-10487643-B2
Application number	US-201515766198-A
Country	US
Kind code	B2
Filing date	Nov 12, 2015
Priority date	Nov 12, 2015
Publication date	Nov 26, 2019
Grant date	Nov 26, 2019

Abstract

Apparatus and methods to image pipes of a multi-pipe structure can be implemented in a variety of applications. The multi-pipe structure may be associated with a well site, such as a multi-casing structure for a production well. Individual pipes of the multi-pipe structure may be investigated in a multi-stage process using delta-like responses, where previous stages provide inputs to subsequent stages. The results of multi-stage processing can be used to image defects in the multi-pipe structure.

First claim

What is claimed is:

1. A method comprising:
transmitting a plurality of electromagnetic signals in a multi-pipe structure, the electromagnetic signals having different frequencies, a different set of frequencies selected for a different pipe of the multi-pipe structure;
estimating, under control of a processor, for each respective pipe of the multi-pipe structure, a defect in the respective pipe by:
using a delta-like response for each pipe of the multi-pipe structure that is excited at the selected set of frequencies of the respective pipe;
using an estimated defect of each pipe, other than the respective pipe, that is excited by the selected set of frequencies of the respective pipe; and
using a received response from transmitting the electromagnetic signal at the selected set of frequencies of the respective pipe; and

generating an image of the multi-pipe structure using the estimated defect in each pipe of the multi-pipe structure.

2. The method of claim 1 , where the different frequencies are selected from the range between 0.1 Hz and 1000 Hz and at least one of the different frequencies used is sensitive mostly to the first pipe.

3. The method of claim 1 , where estimating the defect in a pipe of the multi-pipe structure is derived by solving a linear system of equations that contains the delta-like responses of each pipe of the multi-pipe structure, and received responses measured in at least one receiver to the plurality of electromagnetic signals generated having at least two frequencies by at least one transmitter, where solving the linear system of equations includes solving by a least square method.

4. The method of claim 1 , wherein estimating, for each respective pipe of the multi-pipe structure, the defect in the respective pipe includes estimating the defect for each respective pipe of the multi-pipe structure in ordered stages beginning with an innermost pipe and ending with an outermost pipe in an order based on a diameter of pipes of the multi-pipe structure and with each electromagnetic signal at its selected set of frequencies exciting only the pipe assigned to the selected set of frequencies and pipes having a smaller diameter than the pipe assigned to the selected set of frequencies, wherein averages of the selected sets of frequencies decrease in magnitude in order from an average of the selected set of frequencies assigned to the innermost pipe to an average of the selected set of frequencies assigned to the outermost pipe, wherein processing a first stage of the ordered stages to estimate the defect in the innermost pipe includes acquiring a response from the innermost pipe excited at the selected set of frequencies and applying an a priori calibrated delta-like response for a pipe with known dimensions and electrical properties substantially equal to the innermost pipe; and processing subsequent stages such that each stage k, k being an integer from 2 to a number of pipes of the multi-pipe structure, includes estimating defects on a k th pipe by acquiring responses of the pipes at the selected set of frequencies of the k th pipe and applying known properties of pipes 1 to k−1 of the multi-pipe structure from previous stages along with a priori calibrated delta-like response with known dimensions and electrical properties for pipes 1 to k−1 at the selected set of frequencies of the k th pipe.

5. The method of claim 1 , wherein prior to estimating, for each respective pipe of the multi-pipe structure, a defect in the respective pipe, the method includes estimating permeability and conductivity of pipes of the multi-pipe structure, wherein estimating the conductivity and permeability of the pipes comprises:
selecting a response from a precomputed library of calibrated responses; and
performing an inversion on a non-defected section with nominal thickness of the multi-pipe structure.

6. The method of claim 5 , wherein the method includes:
acquiring data at multiple frequencies for non-defect sections of the pipes of the multi-pipe structure, the data at higher frequencies employed to estimate electrical property values for inner most pipes first;
employing data at lower frequencies for non-defect sections of the pipes of the multi-pipe structure to estimate electrical property values for outer most pipes using electrical properties of inner pipes from employing the data at higher frequencies; and
comparing data for each pipe, after processing with respect to other pipes of the multi-pipe structure, with responses in a database with known electrical property values for pipes having the same dimensions to estimate the electrical properties of the pipes of the multi-pipe structure.

7. The method of claim 5 , wherein the method includes:
acquiring data in a time domain from exciting the pipes of the multi-pipe structure, the data including a decay response of a sensor;
dividing the decay response of the sensor into M sub-regions such that an effect of an m th pipe is being observed from a beginning of an m th sub-region; and
processing values of the decay response at these sub-regions to estimate electrical properties of the pipes.

8. The method of claim 1 , wherein the method includes receiving responses from selected ones of pipes of the multi-pipe structure by using receivers with variable sizes or numbers of turns, or by using transmitters with variable dimensions, variable current levels, or tapped transmitter coils to excite the selected ones of the pipe.

9. A machine-readable storage device having instructions stored thereon, which, when executed by one or more processors of a machine, cause the machine to perform operations, the operations comprising:
transmitting a plurality of electromagnetic signals in a multi-pipe structure, the electromagnetic signals having different frequencies, a different set of frequencies selected for a different pipe of the multi-pipe structure;
estimating, for each respective pipe of the multi-pipe structure, a defect in the respective pipe by:
using a delta-like response for each pipe of the multi-pipe structure that is excited at the selected set of frequencies of the respective pipe;
using an estimated defect of each pipe, other than the respective pipe, that is excited by the selected set of frequencies of the respective pipe; and
using a received response from transmitting the electromagnetic signal at the selected set of frequencies of the respective pipe; and

generating an image of the multi-pipe structure using the estimated defect in each pipe of the multi-pipe structure.

10. The machine-readable storage device of claim 9 , wherein estimating, for each respective pipe of the multi-pipe structure, the defect in the respective pipe includes estimating the defect for each respective pipe of the multi-pipe structure in ordered stages beginning with an innermost pipe and ending with an outermost pipe in an order based on a diameter of pipes of the multi-pipe structure and with each electromagnetic signal at its selected set of frequencies exciting only the pipe assigned to the selected set of frequencies and pipes having a smaller diameter than the pipe assigned to the selected set of frequencies, wherein averages of the selected sets of frequencies decrease in magnitude in order from an average of the selected set of frequencies assigned to the innermost pipe to an average of the selected sets of frequencies assigned to the outermost pipe, wherein processing a first stage of the ordered stages to estimate the defect in the innermost pipe includes acquiring a response from the innermost pipe excited at the selected set of frequencies and applying an a priori calibrated delta-like response for a pipe with known dimensions and electrical

Assignees

• Halliburton Energy Services Inc

Inventors

• San Martin Luis Emilio
• Amineh Reza Khalaj
• Donderici Burkay

Classifications

• E21B47/092

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• G03H1/0005

  Adaptation of holography to specific applications (holographic optical element G02B5/32; holographic scanner G02B26/106; recognition using holographic mask G06V10/88; holographic memories G11B7/0065, G11C13/042) · CPC title

• G01V3/28

  using induction coils · CPC title

• G01V3/00

  Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation · CPC title

• G01B7/34

  for measuring roughness or irregularity of surfaces · CPC title