HYDRAULIC FRACTURE MONITORING BY LOW-FREQUENCY DAS

• US 20170260854A1
• Filed: 03/08/2017
• Published: 09/14/2017
• Est. Priority Date: 03/09/2016
• Status: Active Grant

• Current Assignee: Conocophillips Company (ConocoPhillips)
• Original Assignee: Conocophillips Company (ConocoPhillips)
• Inventors: JIN, Ge, MOSHER, Charles C., FILICE, Frank P., KRUEGER, Kyle R., TURA, Ali, ROY, Baishali, JURICK, Dana M.
• Granted Patent: US 10,287,874 B2
• Time in Patent Office: Days
• CPC Class Codes: E21B 43/26 by forming crevices or fractures
• CPC Class Codes: E21B 47/0224 using seismic or acoustic means
• CPC Class Codes: E21B 47/0228 using electromagnetic energy or detectors therefor
• CPC Class Codes: E21B 47/07 Temperature
• CPC Class Codes: E21B 47/101 using acoustic energy
• CPC Class Codes: E21B 47/102 using electrical indications: using light radiations
• CPC Class Codes: E21B 47/107 using acoustic means
• CPC Class Codes: E21B 47/135 using light waves, e.g. infrared or ultraviolet waves
• CPC Class Codes: G01B 11/161 by interferometric means
• CPC Class Codes: G01H 9/004 using fibre optic sensors light guides per se G02B6/00, acousto-optical devices specially adapted for gating or modulating in optical wave guides G02F1/125
• CPC Class Codes: G01K 11/32 using changes in transmittance, scattering or luminescence in optical fibres
• CPC Class Codes: G01V 1/226 Optoseismic systems
• CPC Class Codes: G01V 1/40 specially adapted for well-logging

Abstract

A method of monitoring hydraulic fracturing using DAS sensors in a treatment well and/or observation well is described. The raw data is transformed using a low pass filter (≦0.05 Hz) and down-sampled to show the signal as the stimulation progresses. The resulting data can be used to optimize the hydraulic fracturing or improve reservoir models for other reservoirs.

Claims

1. ) A method of optimizing a hydraulic fracturing stimulation of a reservoir comprising:

a) installing one or more fiber optic cables in at least one wellbore;

b) attaching said fiber optic cables to an interrogator having interrogation and reflection recording functions;

c) fracturing a stage of a multistage hydraulic fracturing stimulation in a reservoir using pre-determined parameters;

d) interrogating at least one fiber optic cable with an interrogation signal during said fracturing step;

e) recording one or more reflected datasets;

f) converting said one or more reflected datasets into a continuous record;

g) transforming the continuous record with a low-pass filter transform of greater than 0 to 50 millihertz (mHz) to provide a transformed record;

h) down sampling the transformed record;

i) interpreting the down-sampled transformed record to provide an interpreted record;

j) optimizing said pre-determined parameters of said hydraulic fracturing stimulation using said interpreted record to provide optimized parameters; and

,

k) using said optimized parameters for fracturing a subsequent stage in said reservoir.

2. ) The method of claim 1), further comprising repeating steps d-i) a plurality of times.

3. ) The method of claim 1), further comprising step m) producing hydrocarbons from said reservoir.

4. ) The method of claim 1), wherein said at least one wellbore is a treatment wellbore, an observational wellbore, or a combination thereof.

5. ) The method of claim 1), wherein the continuous record is downsampled to 1, 3, 5, 10, 15, 20, 25, 50, 75, or 100 second intervals.

6. ) The method of claim 1), wherein said interrogating step comprises pulsing a laser light at a high frequency.

7. ) The method of claim 1), wherein said interpreting step comprises displaying the transformed record on a computer screen.

8. ) A method of optimizing a hydraulic fracturing stimulation model comprising:

a) installing a fiber optic cable in a treatment well;

b) installing a fiber optic cable in an observational well situated near said treatment well;

c) attaching each fiber optic cable to an interrogator;

d) performing at least one stage of a multistage hydraulic fracturing stimulation in said treatment well according to a hydraulic fracturing plan;

e) interrogating each fiber optic cable with an interrogation signal during said performing step;

f) recording a reflected dataset from each interrogator;

g) converting each reflected dataset into a continuous record by merging the record from the same interrogator;

h) transforming each continuous record with a low-pass filter transform of greater than 0 to 50 mHz and down sampling the data to provide a transformed record;

i) interpreting each transformed record to provide an interpreted record;

j) optimizing said hydraulic fracturing stimulation plan using each interpreted record; and

k) implementing an optimized hydraulic fracturing plan in subsequent fracturing stages in said reservoir.

9. ) The method of claim 8), further comprising repeating steps d-k) a plurality of times.

10. ) The method of claim 8), further comprising producing hydrocarbons from said reservoir.

11. ) The method of claim 8), wherein an additional fiber optic cable is deployed in a second observation well, and steps a-k are repeated in said second observation well.

12. ) The method of claim 8), wherein the continuous record is downsampled to 1, 3, 5, 10, 15, 20, 25, 50, 75, or 100 second intervals.

13. ) The method of claim 8), wherein said interrogating step comprises pulsing a laser light at a high frequency.

14. ) The method of claim 8), wherein said interpreting step comprises displaying the interpreted record on a computer screen.

15. ) The method of claim 8), wherein said reflected datasets records temperature change.

16. ) The method of claim 8), wherein said reflected datasets records formation stress change.