GB/T 35210.1-2023Determination of isothermal adsorption/desorption of methane in shale—Part 1: Static volumetric method (English PDF)

Foreword

This document is in accordance with the provisions of GB/T 1.1-2020 "Guidelines for Standardization Work Part 1: Structure and Drafting Rules for Standardization Documents" drafting.

This document is part 1 of GB/T 35210 "Determination of Isothermal Adsorption/Desorption Capacity of Shale Methane". GB/T 35210 has been issued The following sections.

--- Part 1. Static volume method;

--- Part 2. Gravimetric method.

This document replaces GB/T 35210.1-2017 "Shale Methane Isothermal Adsorption Determination Method Part 1: Volumetric Method", and Compared with GB/T 35210.1-2017, except for structural adjustment and editorial changes, the main technical changes are as follows:

a) The definitions of "free space volume", "Ranks volume" and "Ranks pressure" have been changed (see 3.1, 3.3, 3.4, 3.1, 3.2, 2017 edition 3.3);

b) Added the definitions of "reference cylinder volume", "excess adsorption capacity" and "absolute adsorption capacity" (see 3.2, 3.5, 3.6);

c) Changed the summary of the determination method of shale methane isothermal adsorption/desorption (see Chapter 4, Chapter 4 of the 2017 edition);

d) Increased the requirements for some instruments and equipment required for sample preparation (see 5.1.1);

e) Added the requirements for the vacuum pump in the experimental device (see 5.1.2);

f) The dry base sample preparation method has been changed (see 6.3, 6.3 of the 2017 edition);

g) Changed the distribution of measured pressure points (see 7.3.2, 7.3.2 of the 2017 edition);

h) Added the requirement to vacuumize the sample cylinder before the isothermal adsorption measurement (see 7.5.1);

i) The calculation of excess adsorption at the pressure point of the isothermal adsorption measurement has been changed (see 8.2, 8.2 of the 2017 edition);

j) The method for determining the gas phase density has been added (see 8.3.1);

k) Changed the determination method of Langen volume and Lange pressure (see 8.3.2, 8.3 of the 2017 edition);

l) Added the calculation of absolute adsorption capacity (see 8.3.3);

m) The requirements for precision have been changed (see 9.2, Chapter 10 of the 2017 edition).

This document was first published in 2017, and this is the first revision.

Introduction

Shale methane isothermal adsorption experiment is the most widely used experimental method in evaluating the adsorbed gas content in shale reservoirs, and it is an important indicator of shale gas reserves. important basis for submission. According to different principles, the determination methods of isothermal adsorption/desorption of shale methane are divided into volumetric method and gravimetric method.

GB/T 35210 aims to establish the criteria that are generally applicable to the determination of isothermal adsorption/desorption of shale methane, and consists of two parts.

--- Part 1. Static volumetric method.

--- Part 2. Gravimetric method.

It has been 5 years since GB/T 35210.1-2017 was issued and implemented. During this period, the role of this standard has received more and more attention.

Both theoretical research and practical cognition of experiments have changed. With the deepening of the research, it is generally believed that the adsorption amount measured by the experiment is the methane on the page The excess adsorption amount on the rock surface is far lower than the real adsorption amount, and it is necessary to convert the excess adsorption amount according to the methane adsorption phase density or adsorption phase volume is the absolute adsorption capacity. GB/T 35210.2-2020 has included related terms, definitions and theoretical models such as excess adsorption capacity and absolute adsorption capacity standard. Based on this, this revision has carried out in-depth research on experimental methods, sample preparation, data repeatability and reproducibility, and this document also Refer to the relevant provisions of GB/T 35210.2-2020 to ensure the comprehensiveness, operability and consistency of the relevant content of GB/T 35210.

Important Note: This document does not address all safety issues related to its application. Before using this document, it is the user's responsibility to formulate corresponding safety and protection measures, and ensure compliance with the conditions stipulated in relevant national laws and regulations.

1 Scope

This document describes a static volumetric method for the determination of isothermal adsorption/desorption of methane in shale formations.

This document applies to methane isothermal adsorption capacity of dry base shale samples, methane isothermal adsorption capacity of equilibrium water base shale samples, shale sample The determination of methane isothermal adsorption under formation conditions, and in the process of shale gas production, the absorption of gas in shale due to the decrease of formation pressure Determination of the adsorption isotherm of methane converted to free gas.

2 Normative references

The contents of the following documents constitute the essential provisions of this document through normative references in the text. Among them, dated references For documents, only the version corresponding to the date is applicable to this document; for undated reference documents, the latest version (including all amendments) is applicable to this document.

Preparation method of GB/T 474 coal sample

GB/T 17747.2-2011 Calculation of Compressibility Factor of Natural Gas Part 2: Calculation by Molar Composition

GB/T 19560-2008 Coal high pressure isothermal adsorption test method

3 Terms and Definitions

The following terms and definitions apply to this document.