US 10,120,104 B2 · Downhole surveillance

Abstract

Methods and apparatus for surveillance of a downhole environment: the response of least one optical fiber to an acoustic impulse is sampled and processed to provide an indication of the acoustic signals detected by at least one longitudinal sensing portion of the fiber(s). The data comprises data indicative of at least one characteristic of the acoustic impulse and data indicative of the downhole environment. The data indicative of at least one characteristic of the acoustic impulse is used to interpret the data indicative of the downhole environment to provide an indication of at least one characteristic of the downhole environment. For example, the data indicative of at least one characteristic of the acoustic impulse may provide a ‘signature’ of the impulse, which may be used to deconvolve the data indicative of the downhole environment to provide an indication of at least one characteristic of the downhole environment.

Claims18

Dependent claims

A method of surveillance of a downhole environment in a well comprising:

providing an acoustic impulse, interrogating at least one optical fibre arranged along the path a well bore with optical radiation;
sampling data gathered from said at least one fibre in response to the acoustic impulse;
and processing the sampled data to provide an indication of acoustic signals detected by at least one longitudinal sensing portion of said fibre, wherein the data comprises:
(i) data indicative of at least one characteristic of the acoustic impulse and
(ii) data indicative of downhole environment, wherein the data indicative of at least one characteristic of the acoustic impulse is at least substantially free of convolutions to the impulse imparted by the downhole environment, and the data indicative of the downhole environment includes such convolutions and
the method comprises using the data indicative of at least one characteristic of the acoustic impulse to deconvolve the data indicative of downhole environment to provide an indication of at least one characteristic of the downhole environment.

3 more elements

Apparatus for surveillance of a downhole environment comprising

(i) at least one acoustic source for providing an acoustic impulse;
(ii) at least one optical fibre arranged, in use, to be installed along the path of at least one well bore;
(iii) an optical interrogator for interrogating the at least one fibre with optical radiation;
and for sampling data gathered from said fibre in response to an acoustic impulse;
(iv) processing circuitry for processing said sampled data to provide an indication of acoustic signals received at at least one longitudinal sensing portion of the at least one fibre in response to an acoustic impulse wherein the data comprises
i. data indicative of at least one characteristic of the acoustic impulse and
ii. data indicative of downhole environment, wherein the data indicative of at least one characteristic of the acoustic impulse is at least substantially free of convolutions to the impulse imparted by the downhole environment, and the data indicative of the downhole environment includes such convolutions and for using the data indicative of at least one characteristic of the acoustic impulse to deconvolve the data indicative of downhole environment to provide an indication of at least one characteristic of the downhole environment.

4 more elements

Dependencies are inferred from the claim text.

Downhole surveillance

Life of this patent

Downhole surveillance

Life of this patent

Abstract

Claims18