METHOD AND SYSTEM FOR CALIBRATING A TUBE SCANNER

Abstract

A scanner instrument used for scanning tubing that is being placed into an oil well or being removed from the oil well can be calibrated during retrieval of tubing from the well. Calibrating the tube scanner includes scanning a tubing standard and comparing the data from the standard scan to the known characteristics of the standard. The relationship between the scanned data and the known characteristics can be computed. The relationship between the scanned data and the known characteristics can be used as the calibration function for the scanner. Calibrating the tube scanner can also include scanning a string of tubing segments and then adjusting the data collected. The adjustment is based upon equalizing the data peaks that occur in the scan data at the coupling joints between tube segments.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration of an exemplary system for servicing an oil well where the system scans tubing as the tubing is extracted from or inserted into the well in accordance with an exemplary embodiment of the present invention.

FIG. 2 is a functional block diagram of an exemplary system for scanning tubing that is being inserted into or extracted from an oil well in accordance with an exemplary embodiment of the present invention.

FIG. 3A illustrates a vertical cross-section of an exemplary tube standard for use in calibrating a tube scanner in accordance with an exemplary embodiment of the present invention.

FIG. 3B illustrates a horizontal cross-section of the rotationally variant region of an exemplary tube standard disposed within a circular array of transducer elements in accordance with an exemplary embodiment of the present invention.

FIG. 4 is a flowchart of an exemplary process for scanning tubing that is being inserted into or extracted from an oil well and for calibrating the tube scanner using a tube standard in accordance with an exemplary embodiment of the present invention.

FIG. 5 is a flowchart of an exemplary process for calibrating a tube scanner using a tube standard and stored information about the standard in accordance with an exemplary embodiment of the present invention.

FIG. 6 is a flowchart of an exemplary process for scanning tubing that is being inserted into or extracted from an oil well and for calibrating the tube scanner based on the scanned information in accordance with an exemplary embodiment of the present invention.

Claims

1. A method for calibrating a tubing scanner, comprising: inserting a tubing standard;scanning the tubing standard to produce a calibration scan;analyzing the calibration scan;computing a transform based on the calibration scan; andstoring the transform for application to data obtained during the scanning of tubing.

2. The method of claim 1 further comprising optionally rotating and rescanning the tubing standard a plurality of times; and averaging the plurality of tubing standard scans to produce the calibration scan.

3. The method of claim 1 wherein the tubing standard has a first zone for calibration of a rod sensor.

4. The method of claim 1 wherein the tubing standard a second zone for calibration of a pitting sensor.

5. The method of claim 1 further comprising comparing the calibration scan to a stored scan and computing the transform based on differences between the calibration scan and the stored scan.

6. The method of claim 1 further comprising analyzing the calibration scan and determining a rate of scanning based on a maximum peak height and a baseline.

7. A method for scanning tubing, comprising the steps of: scanning a tubing standard a first time with a tubing scanner to produce a first calibration scan;storing the first calibration scan;analyzing the first calibration scan and computing a transform based upon the first calibration scan;storing the transform;scanning tubing with the tubing scanner;storing the tubing scan data;applying the transform to the tubing scan data to produced transformed tubing scan data;storing the transformed tubing scan data; andanalyzing the transformed tubing scan data.

8. The method of claim 7 further comprising: scanning the tubing standard a second time with a tubing scanner after the scanning of the tubing is complete;comparing the first tubing standard scan with the second tubing scan; andoptionally correcting the tubing scan data to account for differences between the first and second calibration scans.

9. The method of claim 8, further comprising scanning the tubing standard a plurality of times during the scanning of the tubing and computing the transform based upon all of the tubing standard scans.

10. The method of claim 7 further comprising flagging the tubing scan data if the difference between first and second tubing standard scans indicates that the tubing scanner has drifted out of calibration.

11. The method of claim 7 further comprising displaying the transformed tubing scan data.

12. The method of claim 7 further comprising determining the scan speed by comparing the first calibration scan data to a stored calibration scan.

13. The method of claim 7 further comprising: determining the location of collars on the tubing;recording the position of the collars;correlating the tubing scan data to a location on the tubing.

14. The method of claim 7 wherein the scanning of the tubing produces an analog signal.

15. The method of claim 14 further comprising converting the analog signal to a digital signal.

16. An apparatus for scanning tubing, comprising an oil rig;a tubing scanner comprising a plurality of sensors, a calibration module, and a memory device;a tubing standard; andmeans for displaying scan data.

17. The apparatus of claim 16, wherein the sensors are selected from a rod wear sensor or a pitting sensor.

18. The apparatus of claim 16 further comprising an encoder coupled to the tubing scanner for determining speed, velocity or positional information about the tubing.

19. The apparatus of claim 16 further comprising means for transmitting information to a remote location.