Removing ring down effects from sonic waveforms

Patent metadata

Field	Value
Publication number	US-2016018549-A1
Application number	US-201414771773-A
Country	US
Kind code	A1
Filing date	Feb 28, 2014
Priority date	Mar 8, 2013
Publication date	Jan 21, 2016
Grant date	—

Abstract

An illustrative acoustic range finding method including deploying a tool downhole, transmitting a first acoustic waveform with a transmitting acoustic transducer of the tool, receiving a second acoustic waveform with a receiving acoustic transducer of the tool, removing a deterministic waveform from the second acoustic waveform to obtain an echo waveform, and deriving a measurement from said echo waveform.

First claim

What is claimed is:

1 . An acoustic range finding method, comprising:
deploying a tool downhole; transmitting a first acoustic waveform with a transmitting acoustic transducer of the tool; receiving a second acoustic waveform with a receiving acoustic transducer of the tool; removing a deterministic waveform from the second acoustic waveform to obtain an echo waveform; and deriving a measurement from said echo waveform.

2 . The method of claim 1 , further comprising presenting the measurement to a user.

3 . The method of claim 1 , wherein the measurement is one of a distance, an acoustic impedance, or a cement bond quality.

4 . The method of claim 1 , wherein the transmitting acoustic transducer is also the receiving acoustic transducer and wherein the deterministic waveform is a ring down waveform.

5 . The method of claim 1 , further comprising estimating the deterministic waveform by performing a statistical analysis of other waveforms acquired in a time window around an acquisition time of the second acoustic waveform.

6 . The method of claim 1 , further comprising estimating the deterministic waveform by filtering the second acoustic waveform with a statistical low pass filter.

7 . The method of claim 6 , wherein the statistical low pass filter is a mean or median filter.

8 . The method of claim 1 , further comprising estimating the deterministic waveform by:
transforming the second acoustic waveform out of the time-domain; performing a statistical analysis on the transformed second acoustic waveform; and transforming the second acoustic waveform back to the time-domain.

9 . The method of claim 1 , wherein the deterministic waveform comprises a pre-recorded waveform or estimated waveform.

10 . The method of claim 1 , further comprising windowing the second acoustic waveform within a predetermined time window.

11 . The method of claim 1 , wherein deriving the measurement is performed by a downhole processor.

12 . The method of claim 1 , wherein deriving the measurement is performed by a processor at the surface.

13 . An acoustic range finding system, comprising:
a wellbore; a tool arranged within the wellbore and having a transmitting acoustic transducer which transmits a first acoustic waveform and a receiving acoustic transducer which receives a second acoustic waveform; and a processor which removes a deterministic waveform from the second acoustic waveform, thereby resulting in an echo waveform.

14 . The system of claim 13 , further comprising a user interface which displays a measurement corresponding to the echo waveform.

15 . The system of claim 13 , wherein the deterministic waveform is a ring down waveform.

16 . The system of claim 13 , wherein the transmitting and receiving acoustic transducers are the same transducer.

17 . The system of claim 13 , wherein the processor is arranged downhole.

18 . The system of claim 13 , wherein the tool is deployed downhole on a drill string.

19 . The system of claim 13 , wherein the tool is deployed on a wireline.

20 . A non-transitory computer-readable medium comprising computer executable instructions which, when executed by a process, implements a method comprising:
transmitting a first acoustic waveform with a transmitting acoustic transducer of a downhole tool; receiving a second acoustic waveform with a receiving acoustic transducer of the tool; removing a deterministic waveform from the second acoustic waveform to obtain an echo waveform; and deriving a measurement from said echo waveform.

Assignees

• Halliburton Energy Services Inc

Inventors

• Tracadas Philip William

Classifications

• G01V2210/324

  Filtering · CPC title

• G01V2210/3246

  Coherent noise, e.g. spatially coherent or predictable · CPC title

• G01V2210/32

  Noise reduction · CPC title

• G01V1/48 Primary

  Processing data · CPC title

• G01V1/30 Primary

  Analysis (G01V1/50 takes precedence) · CPC title