# US 12,180,830 B2 · Determining an uptake capacity of a core sample

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- Number: US 12,180,830 B2
- Document ID: US12180830B2
- Status: Granted
- Kind: B2
- Application number: 18/163,089
- Filed: 2023-02-01
- Published: 2024-08-01
- Granted: 2024-12-31
- Earliest claimed: 2023-02-01
- Assignees: Saudi Arabian Oil Company
- Applicants: Saudi Arabian Oil Company
- Inventors: Jin-Hong Chen; Stacey M. Althaus; John David Broyles; Houzhu Zhang; Younane N. Abousleiman
- Web page: https://patentgrep.com/patent/US12180830B2

## CPC

- E21B 49/088: {combined with sampling}
- G01N 24/081: {Making measurements of geologic samples, e.g. measurements of moisture, pH, porosity, permeability, tortuosity or viscosity}
- G01R 33/448: {Relaxometry, i.e. quantification of relaxation times or spin density (G01R33/50 takes precedence)}
- G01R 33/4625: {Processing of acquired signals, e.g. elimination of phase errors, baseline fitting, chemometric analysis}
- E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)

## Abstract

Techniques for determining an uptake capacity of a core sample include measuring a nuclear magnetic resonance (NMR) spectrum signal of a test fluid at a particular pressure and entrained in a core sample enclosed in a test cylinder of an NMR pressure cell such that an annulus is defined between the core sample and the test cylinder; deconvolving the NMR spectrum signal into a first NMR spectrum signal portion that is associated with a first portion of the test fluid in the annulus and a second NMR spectrum signal portion that is associated with a second portion of the test fluid entrained in the core sample; and determining a mass of the second portion of the test fluid based at least in part on the first and second NMR spectrum signals.

## Claims

### Claim 1

A method for determining an uptake capacity of a core sample, comprising:
measuring a nuclear magnetic resonance (NMR) spectrum signal of a test fluid at a particular pressure and entrained in a core sample enclosed in a test cylinder of an NMR pressure cell such that an annulus is defined between the core sample and the test cylinder;
deconvolving the NMR spectrum signal into a first NMR spectrum signal portion that is associated with a first portion of the test fluid in the annulus and a second NMR spectrum signal portion that is associated with a second portion of the test fluid entrained in the core sample; and
determining a mass of the second portion of the test fluid based at least in part on the first and second NMR spectrum signals.

### Claim 2 (depends on 1)

The method of claim 1, wherein the particular pressure is less than about 1000 psi.

### Claim 3 (depends on 2)

The method of claim 2, further comprising:
determining a ratio of first and second NMR spin magnetizations from the respective first and second NMR spectrum signals; and
determining a radial dimension of the test cylinder, a radial dimension of the core sample, a distance between NMR coil contacts of an NMR coil of the NMR pressure cell, a mass of the core sample, and a bulk density of the test fluid.

### Claim 4 (depends on 3)

The method of claim 3, wherein determining the ratio of first and second NMR spin magnetizations comprises:
determining the first NMR spin magnetization by integrating the first NMR spectrum signal; and
determining the second NMR spin magnetization by integrating the second NMR spectrum signal.

### Claim 5 (depends on 3)

The method of claim 3, wherein determining the mass of the second portion of the test fluid based at least in part on the first and second NMR spectrum signals comprises:
determining the mass of the second portion of the test fluid based on the radial dimension of the test cylinder, the radial dimension of the core sample, a length of the core sample, the bulk density of the test fluid, and the ratio of the first and second NMR spin magnetizations.

### Claim 6 (depends on 5)

The method of claim 5, wherein determining the mass of the second portion of the test fluid based on the radial dimension of the test cylinder, the radial dimension of the core sample, a length of the core sample, the bulk density of the test fluid, and the ratio of the first and second NMR spectrum signals comprises solving for:
m
pf
=
π
⁢
l
⁢
(
R
2
-
r
2
)
⁢
ρ
γ
,
where mpf is the mass of the second portion of the test fluid, l is the length of the core sample, R is the radial dimension of the test cylinder, r is the radial dimension of the core sample, ρ is the bulk density of the test fluid, and γ is the ratio of the first and second NMR spin magnetizations.

### Claim 7 (depends on 5)

The method of claim 5, further comprising determining a test fluid mass per core sample mass by dividing the mass of the second portion of the test fluid by the mass of the core sample.

### Claim 8 (depends on 1)

The method of claim 1, wherein the particular pressure is more than about 1000 psi.

### Claim 9 (depends on 8)

The method of claim 8, further comprising:
determining a real NMR spectrum of the test fluid in the annulus and the core sample by integrating the NMR spectrum signal over a resonance frequency;
determining a transverse relaxation time modulated NMR spectrum using a spin-echo pulse sequence; and
determining an NMR spectrum difference by subtracting the transverse relaxation time modulated NMR spectrum from the real NMR spectrum.

### Claim 10 (depends on 9)

The method of claim 9, wherein deconvolving the NMR spectrum signal into the first NMR spectrum signal portion that is associated with the first portion of the test fluid in the annulus and the second NMR spectrum signal portion that is associated with the second portion of the test fluid entrained in the core sample comprises:
deconvolving the NMR spectrum difference into the first NMR spectrum signal portion and the second NMR spectrum signal portion.

### Claim 11 (depends on 10)

The method of claim 10, further comprising:
determining a ratio of first and second NMR spin magnetizations from the respective first and second NMR spectrum signals; and
determining a radial dimension of the test cylinder, a radial dimension of the core sample, a distance between NMR coil contacts of an NMR coil of the NMR pressure cell, a mass of the core sample, and a bulk density of the test fluid.

### Claim 12 (depends on 11)

The method of claim 11, wherein determining the ratio of first and second NMR spin magnetizations comprises:
determining the first NMR spin magnetization by integrating the first NMR spectrum signal; and
determining the second NMR spin magnetization by integrating the second NMR spectrum signal.

### Claim 13 (depends on 11)

The method of claim 11, wherein determining the mass of the second portion of the test fluid based at least in part on the first and second NMR spectrum signals comprises:
determining the mass of the second portion of the test fluid based on the radial dimension of the test cylinder, the radial dimension of the core sample, a length of the core sample, the bulk density of the test fluid, and the ratio of the first and second NMR spin magnetizations.

### Claim 14 (depends on 13)

The method of claim 13, wherein determining the mass of the second portion of the test fluid based on the radial dimension of the test cylinder, the radial dimension of the core sample, a length of the core sample, the bulk density of the test fluid, and the ratio of the first and second NMR spectrum signals comprises solving for:
m
pf
=
π
⁢
l
⁢
(
R
2
-
r
2
)
⁢
ρ
γ
,
where mpf is the mass of the second portion of the test fluid, l is the length of the core sample, R is the radial dimension of the test cylinder, r is the radial dimension of the core sample, ρ is the bulk density of the test fluid, and γ is the ratio of the first and second NMR spin magnetizations.

### Claim 15 (depends on 13)

The method of claim 13, further comprising determining a test fluid mass per core sample mass by dividing the mass of the second portion of the test fluid by the mass of the core sample.

### Claim 16 (depends on 1)

The method of claim 1, wherein the test fluid comprises carbon dioxide (CO2).

### Claim 17 (depends on 16)

The method of claim 16, wherein the CO2 comprises 13C labeled CO2.

### Claim 18

A system for determining an uptake capacity of a core sample, comprising:
a nuclear magnetic resonance (NMR) pressure cell, comprising:
a test cylinder configured to hold a test fluid and a core sample; and
an NMR coil positioned around the test cylinder and configured to measure NMR spectrum signals of the test cylinder;
a control system communicably coupled to the NMR coil and configured to perform operations comprising:
measuring a nuclear magnetic resonance (NMR) spectrum signal of a test fluid at a particular pressure and entrained in a core sample enclosed in a test cylinder of an NMR pressure cell such that an annulus is defined between the core sample and the test cylinder;
deconvolving the NMR spectrum signal into a first NMR spectrum signal portion that is associated with a first portion of the test fluid in the annulus and a second NMR spectrum signal portion that is associated with a second portion of the test fluid entrained in the core sample; and
determining a mass of the second portion of the test fluid based at least in part on the first and second NMR spectrum signals.

### Claim 19 (depends on 18)

The system of claim 18, wherein the particular pressure is less than about 1000 psi.

### Claim 20 (depends on 19)

The system of claim 19, wherein the operations further comprise:
determining a ratio of first and second NMR spin magnetizations from the respective first and second NMR spectrum signals; and
determining a radial dimension of the test cylinder, a radial dimension of the core sample, a distance between NMR coil contacts of an NMR coil of the NMR pressure cell, a mass of the core sample, and a bulk density of the test fluid.

### Claim 21 (depends on 20)

The system of claim 20, wherein the operation of determining the ratio of first and second NMR spin magnetizations comprises:
determining the first NMR spin magnetization by integrating the first NMR spectrum signal; and
determining the second NMR spin magnetization by integrating the second NMR spectrum signal.

### Claim 22 (depends on 20)

The system of claim 20, wherein the operation of determining the mass of the second portion of the test fluid based at least in part on the first and second NMR spectrum signals comprises:
determining the mass of the second portion of the test fluid based on the radial dimension of the test cylinder, the radial dimension of the core sample, a length of the core sample, the bulk density of the test fluid, and the ratio of the first and second NMR spin magnetizations.

### Claim 23 (depends on 22)

The system of claim 22, wherein the operation of determining the mass of the second portion of the test fluid based on the radial dimension of the test cylinder, the radial dimension of the core sample, a length of the core sample, the bulk density of the test fluid, and the ratio of the first and second NMR spectrum signals comprises solving for:
m
pf
=
π
⁢
l
⁢
(
R
2
-
r
2
)
⁢
ρ
γ
,
where mpf is the mass of the second portion of the test fluid, l is the length of the core sample, R is the radial dimension of the test cylinder, r is the radial dimension of the core sample, ρ is the bulk density of the test fluid, and γ is the ratio of the first and second NMR spin magnetizations.

### Claim 24 (depends on 22)

The system of claim 22, wherein the operations further comprise determining a test fluid mass per core sample mass by dividing the mass of the second portion of the test fluid by the mass of the core sample.

### Claim 25 (depends on 18)

The system of claim 18, wherein the particular pressure is more than about 1000 psi.

### Claim 26 (depends on 25)

The system of claim 25, wherein the operations further comprise:
determining a real NMR spectrum of the test fluid in the annulus and the core sample by integrating the NMR spectrum signal over a resonance frequency;
determining a transverse relaxation time modulated NMR spectrum using a spin-echo pulse sequence; and
determining an NMR spectrum difference by subtracting the transverse relaxation time modulated NMR spectrum from the real NMR spectrum.

### Claim 27 (depends on 26)

The system of claim 26, wherein the operation of deconvolving the NMR spectrum signal into the first NMR spectrum signal portion that is associated with the first portion of the test fluid in the annulus and the second NMR spectrum signal portion that is associated with the second portion of the test fluid entrained in the core sample comprises:
deconvolving the NMR spectrum difference into the first NMR spectrum signal portion and the second NMR spectrum signal portion.

### Claim 28 (depends on 27)

The system of claim 27, wherein the operations further comprise:
determining a ratio of first and second NMR spin magnetizations from the respective first and second NMR spectrum signals; and
determining a radial dimension of the test cylinder, a radial dimension of the core sample, a distance between NMR coil contacts of an NMR coil of the NMR pressure cell, a mass of the core sample, and a bulk density of the test fluid.

### Claim 29 (depends on 28)

The system of claim 28, wherein the operation of determining the ratio of first and second NMR spin magnetizations comprises:
determining the first NMR spin magnetization by integrating the first NMR spectrum signal; and
determining the second NMR spin magnetization by integrating the second NMR spectrum signal.

### Claim 30 (depends on 28)

The system of claim 28, wherein the operation of determining the mass of the second portion of the test fluid based at least in part on the first and second NMR spectrum signals comprises:
determining the mass of the second portion of the test fluid based on the radial dimension of the test cylinder, the radial dimension of the core sample, a length of the core sample, the bulk density of the test fluid, and the ratio of the first and second NMR spin magnetizations.

### Claim 31 (depends on 30)

The system of claim 30, wherein the operation of determining the mass of the second portion of the test fluid based on the radial dimension of the test cylinder, the radial dimension of the core sample, a length of the core sample, the bulk density of the test fluid, and the ratio of the first and second NMR spectrum signals comprises solving for:
m
pf
=
π
⁢
l
⁢
(
R
2
-
r
2
)
⁢
ρ
γ
,
where mpf is the mass of the second portion of the test fluid, l is the length of the core sample, R is the radial dimension of the test cylinder, r is the radial dimension of the core sample, ρ is the bulk density of the test fluid, and γ is the ratio of the first and second NMR spin magnetizations.

### Claim 32 (depends on 30)

The system of claim 30, wherein the operations further comprise determining a test fluid mass per core sample mass by dividing the mass of the second portion of the test fluid by the mass of the core sample.

### Claim 33 (depends on 18)

The system of claim 18, wherein the test fluid comprises carbon dioxide (CO2).

### Claim 34 (depends on 33)

The system of claim 33, wherein the CO2 comprises 13C labeled CO2.