Estimating change in position of production tubing in a well

Patent metadata

Field	Value
Publication number	US-9541672-B2
Application number	US-201213720521-A
Country	US
Kind code	B2
Filing date	Dec 19, 2012
Priority date	Dec 19, 2012
Publication date	Jan 10, 2017
Grant date	Jan 10, 2017

Abstract

Characterizing a parameter of interest relating to a formation intersected by a borehole. Methods may include estimating the parameter using at least one gravity measurement adjusted to account for a gravity field gradient associated with a change in a frame of reference caused by removal of a reference feature from the borehole. Methods may also include taking at least one prior gravity measurement before removal of the reference feature from the borehole; taking at least one prior gravity measurement after removal of the reference feature from the borehole; estimating the change in the frame of reference based on the prior gravity measurements taken before and after removal of the reference feature; and adjusting the at least one gravity measurement using the estimated change.

First claim

We claim:

1. A method of characterizing a parameter relating to at least one fluid in a formation intersected by a borehole, the method comprising:
taking a first gravity measurement in the borehole using a first gravimeter, the borehole containing a first reference feature;
after taking the first gravity measurement, removing the first gravimeter and the first reference feature from the borehole;
after removing the first gravimeter and the first reference feature from the borehole, positioning a second reference feature and a second gravimeter in the borehole;
taking a second gravity measurement using the second gravimeter;
estimating a difference in position between a position of the first reference feature during the first gravity measurement and a position of the second reference feature during the second gravity measurement using the first gravity measurement and the second gravity measurement;
adjusting at least one additional gravimeter measurement in the borehole using to compensate for the estimated difference; and
using the adjusted at least one additional gravimeter measurement to characterize the parameter.

2. The method of claim 1 , wherein the parameter relates to at least one of: (i) a fluid contact, (ii) water migration, (iii) liquid hydrocarbon migration, (iv) gaseous hydrocarbon migration, (v) gas migration, and (vi) fluid saturation.

3. The method of claim 1 , further comprising:
wherein the difference in position between the first reference feature and the second reference feature is estimated using an estimated gravitational field gradient at at least one of the first gravity measurement and the second gravity measurement.

4. The method of claim 3 , wherein the estimated gravitational field gradient is obtained using at least one of: i) a plurality of measurements of the first gravimeter; ii) a plurality of measurements of the second gravimeter, iii) a gradiometer, iv) at least one measurement from each of the first gravimeter and the second gravimeter; v) at least one measurement from each of the first gravimeter and a third gravimeter mounted on a tool with the first gravimeter; and vi) at least one measurement from each of the second gravimeter and a fourth gravimeter mounted on a tool with the second gravimeter.

5. The method of claim 1 , wherein at least one of the first reference feature and the second reference feature is positioned in the borehole and along a production tubing.

6. The method of claim 1 , wherein the second reference feature is different from the first reference feature.

7. The method of claim 1 , wherein the second gravimeter is the same as the first gravimeter.

8. The method of claim 1 , wherein the second gravimeter is different from the first gravimeter.

9. The method of claim 1 , further comprising:
estimating a difference in orientation between the first gravimeter and the second gravimeter; and
wherein adjusting the at least one gravimeter measurement comprises using to compensate for the estimated difference in orientation.

10. The method of claim 1 , further comprising lowering the first gravimeter into the borehole.

Assignees

• Baker Hughes Inc

Inventors

• Edwards Carl M
• Georgi Daniel T
• Loermans Antonius M

Classifications

• G01V7/00 Primary

  Measuring gravitational fields or waves; Gravimetric prospecting or detecting · CPC title