Methods and Systems Employing a Flow Prediction Model Based on Acoustic Activity and Proppant Compensation

• US 20160266276A1
• Filed: 10/17/2014
• Published: 09/15/2016
• Est. Priority Date: 10/17/2014
• Status: Active Grant

• Current Assignee: Halliburton Energy Services Incorporated (Halliburton Company)
• Original Assignee: Halliburton Energy Services Incorporated (Halliburton Company)
• Inventors: STOKELY, Christopher Lee, NUNES, Leonardo de Oliveira
• Granted Patent: US 10,591,639 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: E21B 43/00 Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells applicable only to water E03B
• CPC Class Codes: E21B 43/26 by forming crevices or fractures
• CPC Class Codes: E21B 43/267 reinforcing fractures by propping
• CPC Class Codes: E21B 47/00 Survey of boreholes or wells monitoring pressure or flow of drilling fluid E21B21/08
• CPC Class Codes: E21B 47/06 Measuring temperature or pressure
• CPC Class Codes: E21B 47/07 Temperature
• CPC Class Codes: E21B 47/107 using acoustic means
• CPC Class Codes: E21B 47/12 Means for transmitting measuring-signals or control signals from the well to the surface, or from the surface to the well, e.g. for logging while drilling
• CPC Class Codes: E21B 47/135 using light waves, e.g. infrared or ultraviolet waves
• CPC Class Codes: G01N 21/01 Arrangements or apparatus for facilitating the optical investigation
• CPC Class Codes: G01N 21/1702 with opto-acoustic detection, e.g. for gases or analysing solids
• CPC Class Codes: G01N 21/45 using interferometric methods; using Schlieren methods
• CPC Class Codes: G01V 1/00 Seismology; Seismic or acoustic prospecting or detecting
• CPC Class Codes: G01V 11/00 Prospecting or detecting by methods combining techniques covered by two or more of main groups G01V1/00 - G01V9/00
• CPC Class Codes: G01V 11/002 Details, e.g. power supply systems for logging instruments, transmitting or recording data, specially adapted for well logging, also if the prospecting method is irrelevant means for transmitting well survey signals E21B47/12; signal transmission systems in general G08C; transmission in general H04B
• CPC Class Codes: G01V 20/00 Geomodelling in general

Abstract

An example method includes providing source light to an optical fiber deployed in a downhole environment, receiving backscattered light from the optical fiber, and producing one or more optical interferometry signals from the backscattered light. The method also includes converting each of the one or more optical interferometry signals to an electrical signal and digitizing each electrical signal to obtain one or more digitized electrical signals. The method also includes deriving acoustic activity values as a function of time and position from the one or more digitized electrical signal. The method also includes applying at least some of the acoustic activity values to a flow prediction model to obtain a predicted fluid flow as a function of time, wherein the flow prediction model includes a proppant compensation value or factor. The method also includes storing or displaying the predicted fluid flow.

Claims

1. A method, comprising:

obtaining distributed measurements of acoustic energy as a function of time and position downhole;

deriving acoustic activity values as a function of time and position from the one or more distributed measurements;

applying at least some of the acoustic activity values to a flow prediction model to obtain a predicted fluid flow for a downhole perforation cluster as a function of time, wherein the flow prediction model includes a proppant compensation value or factor; and

storing or displaying the predicted fluid flow.

2. The method of claim 1, wherein the distributed measurements are derived from:

providing source light to an optical fiber deployed in a downhole environment;

receiving backscattered light from the optical fiber and producing one or more optical interferometry signals from the backscattered light; and

converting each of the one or more optical interferometry signals to an electrical signal and digitizing each electrical signal to obtain one or more digitized electrical signals.

3. The method of claim 1, further comprising applying at least some of the acoustic activity values to the flow prediction model to obtain a predicted fluid flow for each of a plurality of perforation clusters.

4. The method of claim 1, further comprising calibrating the flow prediction model based on a comparison of a sum of predicted fluid flow for each of at least one perforation cluster and a surface fluid flow without proppants.

5. The method of claim 1, further comprising calibrating the flow prediction model based on a comparison of acoustic activity values obtained with and without a surface fluid flow.

6. The method of claim 1, further comprising calibrating the flow prediction model based on a comparison of acoustic activity values obtained with and without proppant.

7. The method of claim 1, further comprising averaging acoustic activity values input to the flow prediction model in accordance with a predetermined spacing or timing criteria.

8. The method of claim 1, further comprising normalizing acoustic activity values input to the flow prediction model based on a noise-floor identified for at least one perforation cluster.

9. The method of claim 1, wherein deriving the acoustic activity values comprises calculating phase energy for each of a limited number of frequency sub-bands of a distributed acoustic sensing signal obtained from each digitized electrical signal.

10. The method of claim 1, wherein the proppant compensation factor or value is a function of a downhole proppant estimate.

11. The method of claim 1, wherein the proppant compensation factor or value is a function of an acoustic attenuation estimate.

12. The method of claim 1, further comprising displaying a plan based on the predicted fluid flow, the plan related to at least one of well treatment operations and proppant injection operations.

13. The method of claim 1, further comprising initiating or adjusting a downhole operation based on the predicted fluid flow, the downhole operation related to at least one of well treatment operations or proppant injection operations.

14. A system, comprising:

an optical fiber;

a light source to provide source light to the optical fiber;

a receiver coupled to the optical fiber, wherein the receiver comprises;

at least one optical fiber coupler that receives backscattered light and that produces one or more optical interferometry signals from the backscattered light; and

photo-detectors that produce an electrical signal for each of the one or more optical interferometry signals;

at least one digitizer that digitizes each electrical signal to obtain one or more digitized electrical signals; and

at least one processing unit that processes the one or more digitized electrical signal to obtain acoustic activity values as a function of time and position, wherein the at least one processing unit applies at least some of the acoustic activity values to a flow prediction model to obtain a predicted fluid flow for a downhole perforation cluster as a function of time, and wherein the flow prediction model includes a proppant compensation value or factor.

15. The system of claim 14, wherein the at least one processing unit applies at least some of the acoustic activity values to the flow prediction model to obtain a predicted fluid flow for each of at least one perforation cluster.

16. The system of claim 14, wherein the at least one processing unit calibrates the flow prediction model based on at least one comparison selected from the list consisting of a comparison of a sum of predicted fluid flow for each of at least one perforation cluster and a surface flow rate, a comparison of acoustic activity values obtained with and without a surface fluid flow, and a comparison of acoustic activity values obtained before and after proppant is added.

17. The system of claim 14, wherein the at least one processing unit modifies acoustic activity values input to the flow prediction model based on at least one operation selected from the list consisting of averaging acoustic activity values in accordance with a predetermined spacing or timing criteria and normalizing acoustic activity values based on a noise-floor value identified for at least one perforation cluster.

18. The system of claim 14, wherein the at least one processing unit adjusts the proppant compensation factor or value as a function of a downhole proppant estimate or an acoustic attenuation estimate.

19. The system of claim 14, further comprising a monitor in communication with the at least one processing unit, wherein the at least one processing unit causes the monitor to display a plan based on the predicted fluid flow, the plan related to at least one of well treatment operations and proppant injection operations.

20. The system of claim 14, wherein the at least one processing unit provides a control signal to initiate or adjust a downhole operation based on the predicted fluid flow, the downhole operation related to at least one of well treatment operations and proppant injection operations.