Multi-variable workflow for cement evaluation in multiple casing strings

Patent metadata

Field	Value
Publication number	US-10067262-B2
Application number	US-201515111942-A
Country	US
Kind code	B2
Filing date	Sep 4, 2015
Priority date	Sep 10, 2014
Publication date	Sep 4, 2018
Grant date	Sep 4, 2018

Abstract

Sonic data, ultrasonic data, density data, cased-hole neutron data, and open-hole neutron data of the wellbore are obtained. The sonic and ultrasonic data provides the amplitude, frequency, and phase of the altered sonic and ultrasonic waves. The far counts, near counts, and energy spectrum are obtained from density data, cased-hole (CH) neutron data, and open-hole (OH) neutron data. The amplitude, frequency, and phase provide the interface densities of the first, second, and third interfaces. The hydrogen index (HI) of the formation and the cased wellbore are obtained from the CH and OH neutron data. The widths of the second and third interfaces are obtained from the HI's and the densities of the second and third interfaces.

First claim

What is claimed is:

1. A method, comprising:
introducing a tool string into a wellbore drilled through a formation, the wellbore at least partially lined with a first casing and a second casing concentrically overlapping a portion of the first casing, wherein a first annulus is defined between the first and second casings and filled with a first annular media, and a second annulus is defined between the second casing and a wall of the wellbore and filled with a second annular media;
obtaining sonic data of the first and second annular media using a sonic wave emitted from a sonic tool included in the tool string;
obtaining, from the sonic data, an amplitude, a frequency, and a phase of the sonic wave as altered by the first and second annular media;
obtaining a first density value of the first annular media using the amplitude, the frequency, and the phase obtained from the sonic data;
obtaining ultrasonic data of the first annular media using an ultrasonic wave emitted from an ultrasonic tool included in the tool string;
obtaining, from the ultrasonic data, an amplitude, a frequency, and a phase of the ultrasonic wave as altered by the first annular media;
obtaining a second density value of the first annular media using the amplitude, the frequency, and the phase obtained from the ultrasonic data;
obtaining density data of the first annular media using gamma rays emitted by a density tool included in the tool string;
obtaining, from the density data, far counts, near counts, and an energy spectrum of the first annular media;
obtaining cased-hole neutron data using a neutron porosity tool included in the tool string;
obtaining, from the cased-hole neutron data, far counts and near counts of gamma rays generated via neutron scattering due to one or more of the first and second casings, the first and second annular media, and the formation, and to obtain an energy spectrum of the formation and the first and second annular media;
obtaining open-hole neutron porosity log data from measurements performed on the formation prior to casing the wellbore;
obtaining, from the open-hole neutron porosity log data, far counts and near counts of gamma rays generated due to neutron scattering in the formation, and to obtain an energy spectrum of the formation; and
determining a bond quality between cement in the first annular media and the first and second casings, and a bond quality between cement in the second annular media and the second casing and the formation based on the first density value, the second density value, the density data, the cased-hole neutron data, and the open-hole neutron porosity log data.

2. The method of claim 1 , further comprising:
performing a first inverse modeling operation on the amplitude, the frequency, and the phase obtained from the sonic data to obtain the first density value of the first annular media based on an acoustic impedance characteristic of the first annular media;
performing a second inverse modeling operation on the amplitude, the frequency, and the phase obtained from the ultrasonic data to obtain the second density value of the first annular media based on the acoustic impedance characteristic of the first annular media; and
comparing the first density value and the second density value to determine whether the first and second density values are within a desired proximity of each other.

3. The method of claim 2 , further comprising obtaining a first interface density from the first density value when the first and second density values are within a desired proximity of each other, the first interface density being a density value of an interface of the first casing and the first annular media.

4. The method of claim 2 , further comprising recalculating at least one of the first density value and the second density value when the first and second density values are not within the desired proximity of each other.

5. The method of claim 3 , further comprising
obtaining a third density value of the first annular media by performing a third inverse modeling operation using the first interface density, and far counts, near counts, and an energy spectrum of the first annular media obtained from the density data;
obtaining a second interface density based on the third density value, the second interface density being a density value of the interface of the first casing and the first annular media; and
comparing the first interface density with the second interface density and obtaining a density of the interface of the first casing and the first annular media when the first and second interface densities are within a desired proximity of each other.

6. The method of claim 5 , further comprising recalculating at least one of the first and second density values when the first and second interface densities are not within the desired proximity of each other.

7. The method of claim 5 , further comprising obtaining a first width of the interface at the first casing and the first annular media when the first and second interface densities are within the desired proximity of each other.

8. The method of claim 7 , further comprising:
performing a fourth inverse modeling operation using the density of the first annular media and the first width to calculate a second interface density and a third interface density, the second interface density being a density value of an interface of the second casing and the first annular media and the third interface density being a density value of an interface of the second casing and the second annular media;
calculating an annular media hydrogen index of each of the first annular media and the second annular media;
calculating an open-hole hydrogen index of the formation using the open-hole neutron porosity log data, and a cased-hole hydrogen index of the wellbore using the cased-hole neutron data;
calculating a second width of the interface of the second casing and the first annular media and a third width of the interface of the second casing and the second annular media via a fifth inverse modeling operation performed on the second and third interface densities, the annular media hydrogen index, the open-hole hydrogen index, and the cased-hole hydrogen index;
performing a sixth inverse modeling operation using the second and third widths to calculate the second interface density and the third interface density; and
comparing the second interface density and the third interface density calculated via the fourth inverse modeling operation with the second interface density and the third interface density calculated via the sixth inverse modeling operation.

9. The method of claim 8 , further comprising obtaining the first, second, third interface densities and a fourth interface density when the second interface density calculated via the fourth inverse modeling operation is within a desired proximity of the second interface density calculated via the sixth inverse modeling operation, and the third interface density calculated via the fourth inverse modeling operation is within a desired proximity of the third interface density calculated via the sixth inverse modeling operation, the fourth interface density being a density value of an interface of the formation and the second annular media.

10. The method of claim 8 , further comprising recalculating at least one of the second interface density and the third interface density calculated via the fourth inverse modeling operation when the second interface density calculated via the fourth inverse modeling operation is not within a desired proximity of the second interface density calculated via the sixth inverse modeling operation, or when the third interface density calculated via the f

Assignees

• Halliburton Energy Services Inc

Inventors

• Quintero Luis F
• Foianini Ivo
• Fadul Javier

Classifications

• G01V5/104

  and detecting secondary Y-rays as well as reflected or back-scattered neutrons · CPC title

• G01V1/40

  specially adapted for well-logging · CPC title

• G01V5/08

  using primary nuclear radiation sources or X-rays {(, e.g. for inducing radioactivity; investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays, neutrons G01N23/00)} · CPC title

• G01V11/002 Primary

  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 title

• G01V5/145

  using a neutron source combined with a gamma- or X-ray source · CPC title