Distributed seismic sensing for in-well monitoring

Patent metadata

Field	Value
Publication number	US-10295690-B2
Application number	US-201314912088-A
Country	US
Kind code	B2
Filing date	Sep 18, 2013
Priority date	Sep 18, 2013
Publication date	May 21, 2019
Grant date	May 21, 2019

Abstract

A method and apparatus for seismic sensing is described. The apparatus includes an outer cable coupled to a formation and an outer fiber component proximate to the outer cable. When seismic P- and S-waves propagate from the formation to the outer cable, strain is placed on the outer fiber cable, which may be measured by a distributed acoustic sensing system coupled to the outer fiber cable. An inner cable positioned within the outer cable includes a corresponding inner fiber component. The innerduct between the outer and inner cables is filled with a gas or fluid which allows only P-waves to propagate to the inner cable. Those P-waves induce strain on the inner fiber component, which may be measured by the distributed acoustic sensing system. By measuring the seismic P- and S-waves at the outer fiber component, and the isolated seismic P-wave at the inner fiber component, it is possible to calculate an isolated seismic S-wave measurement. Methods for deploying the seismic sensing apparatus are also described.

First claim

What is claimed is:

1. A seismic sensing system, comprising:
an outer cable mechanically coupled to a formation, wherein the outer cable experiences one or more seismic waves propagating through the formation;
an outer fiber component embedded in an exterior of the outer cable, wherein the outer fiber component is coupled to a distributed acoustic sensing system, and wherein a centralizing component is disposed exterior to the outer cable;
a solid between the seismic sensing system and the formation, wherein the solid provides mechanical coupling between the seismic sensing system and the formation, and wherein the solid comprises fillers to optimize acoustic impedance;
an inner cable disposed within the outer cable;
an inner fiber component proximate to the inner cable, wherein the inner fiber component is coupled to the distributed acoustic sensing system, and wherein the inner fiber component is more sensitive to strain and displacement measurements than the outer fiber component;
an innerduct between the outer cable and the inner cable, wherein the innerduct comprises one of a liquid or a gas that minimizes transference of one or more seismic S-waves of the one or more seismic waves from the outer cable to the inner cable while allowing transference of one or more seismic P-waves of the one or more seismic waves;
a plurality of centralizers disposed in the innerduct between the outer cable and the inner cable, wherein the plurality of centralizers allow propagation of the one or more seismic P-waves to the inner cable while minimizing propagation of the one or more seismic S-waves to the inner cable, wherein the inner fiber measures the one or more seismic P-waves; and
wherein the inner fiber component measures the one or more seismic P-waves when the one or more seismic P-waves experienced by the inner cable cause strain and displacement on the inner fiber component; and
wherein the outer fiber component measures a combined effect of the one or more seismic P-waves and the one or more seismic S-waves, when the one or more seismic P-waves and the one or more seismic S-waves experienced by the outer cable cause strain and displacement on the outer fiber component.

2. The seismic sensing system of claim 1 , wherein the innerduct is filled with a gas.

3. The seismic sensing system of claim 1 , wherein the innerduct is filled with a liquid.

4. The seismic sensing system of claim 1 , wherein the outer cable includes a strength member.

5. The seismic sensing system of claim 4 , further comprising one or more magnets affixed to the inner cable.

6. The seismic sensing system of claim 1 , wherein the plurality of centralizers are soft gel centralizers.

7. The seismic sensing system of claim 1 , wherein the outer fiber component is wrapped helically around the outer cable.

Assignees

• Halliburton Energy Services Inc

Inventors

• Jaaskelainen Kari-Mikko
• Mitchell Ian B

Classifications

• G01V1/40 Primary

  specially adapted for well-logging · CPC title

• G01V1/284

  Application of the shear wave component and/or several components of the seismic signal · CPC title

• G01V1/226

  Optoseismic systems · CPC title