# US 2025/0085262 A1 · Method and apparatus to measure hydrogen sulfide concentration in a gas mixture with gamma ray absorption

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- Number: US 2025/0085262 A1
- Document ID: US20250085262A1
- Status: Published application
- Kind: A1
- Application number: 18/720,395
- Filed: 2022-12-21
- Published: 2025-03-13
- Earliest claimed: 2021-12-21
- Assignees: Schlumberger Technology Corporation
- Applicants: Schlumberger Technology Corporation
- Inventors: Sukru Sarac; Diogo Piasseski; Yue Sum Wilson Chin; Guillaume Jolivet
- Web page: https://patentgrep.com/patent/US20250085262A1

## CPC

- G01N 33/0044: {Sulphides, e.g. H2S}
- G01N 23/06: and measuring the absorption
- 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)

## Abstract

Embodiments described herein provide methods and apparatuses to determine hydrogen sulfide (and carbon dioxide) concentration in a gas mixture using gamma photon absorption analysis.

## Claims

### Claim 1

A method, comprising:
measuring attenuation of gamma photons in a gas mixture consisting essentially of hydrocarbons, CO2, and H2S; and
determining composition of the gas mixture using the measured attenuation.

### Claim 2 (depends on 1)

The method of claim 1, wherein the gamma photons are photons at two energy levels.

### Claim 3 (depends on 2)

The method of claim 2, further comprising determining linear attenuation coefficients for components of the gas by measuring attenuation of the gamma photons at two energy levels in a representative gas of known composition consisting essentially of hydrocarbons, CO2, and H2S.

### Claim 4 (depends on 1)

The method of claim 1, wherein the gamma photons are photons at one energy level.

### Claim 5 (depends on 3)

The method of claim 3, wherein determining the linear attenuation coefficient for the components of the gas comprises computing density of the hydrocarbons in the representative gas using an equation of state model with temperature and pressure as input.

### Claim 6 (depends on 3)

The method of claim 3, wherein determining the linear attenuation coefficients for components of the gas comprises calculating a density of the representative gas and determining an apparent density of components of the representative gas from the measured attenuation of the gamma photons by the representative gas, the calculated density, and literature values for mass attenuation coefficients of the components of the gas.

### Claim 7 (depends on 6)

The method of claim 6, wherein determining the apparent density of component of the representative gas is performed using an interative computation.

### Claim 8 (depends on 3)

The method of claim 3, wherein determining linear attenuation coefficients for components of the gas comprises treating the hydrocarbons in the gas as a single component.

### Claim 9

A method, comprising:
measuring attenuation of gamma photons in a gas mixture consisting essentially of hydrocarbons, CO2, and H2S;
measuring temperature and pressure of the gas mixture; and
determining composition of the gas mixture using the measured attenuation, temperature, and pressure.

### Claim 10 (depends on 9)

The method of claim 9, wherein the gamma photons are photons at two energy levels.

### Claim 11 (depends on 10)

The method of claim 10, further comprising determining linear attenuation coefficients for components of the gas by measuring attenuation of the gamma photons at two energy levels in a representative gas of known composition consisting essentially of hydrocarbons, CO2, and H2S.

### Claim 12 (depends on 9)

The method of claim 9, wherein the gamma photons are photons at one energy level.

### Claim 13 (depends on 11)

The method of claim 11, wherein determining the linear attenuation coefficient for the components of the gas comprises computing density of the representative gas using an equation of state model with temperature and pressure as input.

### Claim 14 (depends on 11)

The method of claim 11, wherein determining the linear attenuation coefficients for components of the gas comprises computing a density of the representative gas and determining an apparent density of components of the representative gas from the measured attenuation of the gamma photons by the representative gas, the computed density, and literature values for mass attenuation coefficients of the components of the gas.

### Claim 15 (depends on 14)

The method of claim 14, wherein determining the apparent density of components of the representative gas is performed using an interative computation.

### Claim 16 (depends on 11)

The method of claim 11, wherein determining linear attenuation coefficients for components of the gas comprises treating the hydrocarbons in the gas as a single component.

### Claim 17

A method of determining composition of a mixture of H2S, CO2, and hydrocarbons, the method comprising:
measuring attenuation of gamma photons in a gas mixture consisting essentially of hydrocarbons, CO2, and H2S;
measuring temperature and pressure of the gas mixture;
determining linear attenuation coefficients for the components of the gas mixture by measuring attenuation of the gamma photons in a representative gas mixture of H2S, CO2, and hydrocarbons; and
determining composition of the gas mixture using the measured attenuation and the determined linear attenuation coefficients.

### Claim 18 (depends on 17)

The method of claim 17, wherein measuring attenuation of the gamma photons in the gas mixture and in the representative gas mixture uses gamma photons at two energy levels.

### Claim 19 (depends on 17)

The method of claim 17, wherein measuring attenuation of the gamma photons in the gas mixture and in the representative gas mixture uses gamma photons at one energy level.

### Claim 20 (depends on 17)

The method of claim 17, wherein determining linear attenuation coefficients for the components of the gas mixture comprises iteratively calculating composition of the representative gas mixture based on the measured attenuation of gas photons in the representative gas mixture, measured density of the representative gas mixture, and measured temperature and pressure of the representative gas mixture.