ISO/TR 27925:2023

TECHNICAL ISO/TR
REPORT 27925
First edition
2023-07
Carbon dioxide capture,
transportation and geological
storage — Cross cutting issues — Flow
assurance
Captage, transport et stockage géologique du dioxyde de carbone —
Questions transversales — Maintien de l'écoulement
Reference number
ISO/TR 27925:2023(E)
© ISO 2023

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ISO/TR 27925:2023(E)
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ISO/TR 27925:2023(E)
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Abbreviated terms . 2
5 Overview of the necessity of flow assurance in CCS projects . 3
5.1 General . 3
5.2 Reasons to maintain flow assurance . 3
5.3 Potential factors affecting flow of CO streams at individual components of CCS
2
projects . 4
5.3.1 General . 4
5.3.2 CO sources . . . 5
2
5.3.3 Capture facilities . 5
5.3.4 Transportation . 5
5.3.5 Field distribution . 5
5.3.6 Injection wells . 6
5.3.7 Storage reservoirs . 6
5.3.8 Optional components . 7
5.4 Providing flow assurance . 7
5.4.1 General . 7
5.4.2 Technical design. 7
5.4.3 Operational procedures and work-flows . 7
5.4.4 Overarching project management . 8
6 Fluid composition and physical properties . 8
6.1 General . 8
6.2 CO phase behaviour and thermophysical properties — Key features . 9
2
6.3 Modelling properties of pure CO .12
2
6.4 Properties of impure CO — Phenomena and their modelling .13
2
6.5 Individual impurities . 16
6.5.1 General . 16
6.5.2 Water . 16
6.5.3 Nitrogen and argon . 16
6.5.4 Hydrogen . 16
6.5.5 Oxygen . 17
6.5.6 Carbon monoxide . 17
6.5.7 Methane and ethane . 17
6.5.8 Propane and other aliphatic hydrocarbons . 17
6.5.9 Nitrogen and sulfur oxides . 17
6.5.10 Hydrogen sulfide . 18
6.5.11 Carbonyl sulfide . 18
6.5.12 Ammonia . 18
6.5.13 Amines . 18
6.5.14 Benzene, toluene, ethylxylene and xylene . 18
6.5.15 Methanol . 18
6.5.16 Ash, dust, metals and other particulate matter . 19
6.5.17 Naphthalene . 19
6.5.18 Volatile organic compounds . 19
6.5.19 Chlorine . 19
6.5.20 Hydrogen chloride, hydrogen fluoride and hydrogen cyanide . 19
6.5.21 Glycols . 19
6.6 Effects of reactive impurities — Phenomena and their modelling . 20
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ISO/TR 27925:2023(E)
6.6.1 General .20
6.6.2 Formation of corrosive aqueous phases . 20
6.6.3 CO specifications . 22
2
6.6.4 Modelling of formation of corrosive aqueous phases .22
6.6.5 Depressurisation and impact of reactive impurities .23
6.6.6 Corrosion issues in CO injection wells . 23
2
6.6.7 Monitoring reactive impurities in the CO stream .23
2
6.6.8 Particle, wear and clogging . 24
6.7 Modelling of CO stream properties in commercial flow assurance tools . 24
2
6.7.1 General . 24
6.7.2 Joule-Thomson effect .25
6.7.3 Viscosity . 26
6.7.4 Flow assurance simulation for CO transportation in pipes .28
2
7 CO pipeline transport and well injection .29
2
7.1 Operation under single-phase flow conditions .30
7.1.1 General .30
7.1.2 Fluid hammer . 31
7.1.3 Shut-down of pipeline and well . 31
7.1.4 Start-up and restart of pipeline transport and well injection . 32
7.2 Normal operation under two-phase flow conditions . 33
7.2.1 General . 33
7.2.2 Identification of two-phase flow in the pipeline and well .33
7.2.3 State of the art of modelling two-phase CO flow in pipelines and wells .34
2
7.2.4 Shut-down and restart .34
7.2.5 Cavitation . 35
7.3 Special operation with two-phase flow . . 35
7.3.1 Depressurization . 35
7.3.2 Planned and un-planned pipeline pressure release .36
7.3.3 Well blowout . 37
7.3.4 Leakage detection . 37
7.4 Other issues . 37
7.4.1 Dry ice formation . 37
7.4.2 Hydrates . 37
7.5 Ready for operation . 39
8 Fluid flow in storage reservoirs .40
8.1 General .40
8.2 Depleted gas reservoirs . 42
8.3 Saline aquifers .44
8.4 EOR operations . 45
Bibliography .48
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ISO/TR 27925:2023(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
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ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
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Attention is drawn to the possibility that some of the elements of this document may be the subject of
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www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 265, Carbon dioxide capture,
transportation, and geological storage.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
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ISO/TR 27925:2023(E)
Introduction
Flow assurance can be defined as an engineering discipline that is required to understand the
behaviour of fluids inside vessels, pipes or porous media at flowing and at static conditions. Flow
assurance provides input to design activities, such as pipeline design or risk analysis. It emerged as an
engineering discipline in the oil and gas industry in the 1990s. Flow assurance analysis is delivered in
the oil and gas industry by methodical numerical simulation of each pipeline and injection/production
well operating case, often using flow assurance software to facilitate the analysis.
In relation to carbon dioxide capture and storage (CCS), flow assurance seeks to maintain the
continuous supply of the CO stream from the capture plant, through the transportation system and
2
into the geological reservoir via injection wells. Flow assurance is required to demonstrate that all
foreseeable operating modes of all components of CCS projects, planned and unplanned, are predictable,
reliable and safe. It achieves this through analysis of the CO stream flowing as a fluid in the various
2
components of a CCS project’s systems, from capture through to geological storage (capture, transport,
injection and storage).
Some of the key issues of interest addressed by flow assurance analysis include:
— the total network or project hydraulic capacity requirements necessary for determining pipeline,
injection well and reservoir operating parameters;
— management of transient operations, such as those caused by varying injection rates, varying CO
2
stream supply and during slugging, surging and start-up and shut-down operations;
— thermal management under various operational scenarios to ensure that the variations of fluid
temperature are within the operating constraints of the system;
— fluid phase behaviour and physical properties as a function of CO stream composition;
2
— hydrate management and control, resulting from Joule-Thomson effects such as pressure drop
across pressure reducing valves, orifice plates and flow metering devices; and
— planned and unplanned de-pressurization of systems, such as that resulting from a pipeline rupture,
well blowout or controlled venting of pipeline and equipment during maintenance activities.
Most of the above issues can be addressed by dedicated flow assurance modelling software and tools,
in which both thermodynamic and hydrodynamic behaviours of fluids in technical components such as
pipelines or wells are modelled. The thermodynamic properties and transport properties of fluids are
closely related to their chemical composition and their associated amount or concentration. Significant
differences in thermodynamic behaviour of fluid of different compositions can be observed and these
differences can lead to different hydrodynamic behaviour of the flow. Therefore, fluid thermodynamic
properties are a critical input to the dynamic flow models.
Existing CCS system modelling of technical components has mainly been limited to single phase CO .
2
Given significant storage capacity suitable for permanent CO storage exists in depleted hydrocarbon
2
reservoirs, which can be initially at pressures where CO can be subject to two-phase flow conditions,
2
the CO stream in the pipeline and injection well can be subject to two-phase flow conditions, i.e. a
2
combination of two CO phases, gas and liquid. Two-phase flow can also occur during transient
2
operations such as opening up, closing in or depressurization of pipelines or wells. Within underground
reservoirs two-phase flow is generally expected involving the injected CO stream as well as formation
2
fluids that will have to be mobilized. Facilitating unhindered flow of the CO streams in CCS projects
2
requires the inclusion of reservoir fluids (natural gas, water or crude oil) and relevant processes in
the storage reservoir in the flow assurance analysis. Two-phase flow cases, such as in the examples
mentioned, are a more complex challenge for flow assurance modelling compared to flow assurance in
oil and gas transportation and injection/production well infrastructure.
Existing commercial software tools for flow assurance analysis are utilized for modelling the planned
and unplanned operation modes for the various components of the CCS system, including the reservoir
management component. These tools predict fluid behaviour and properties in the operating system. As
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ISO/TR 27925:2023(E)
input, this modelling requires input data such as the CO stream composition, the physical geometry of
2
relevant infrastructure such as pipelines, injection wells and the receiving reservoir, and the operating
conditions which include:
— steady-state and transient processes;
— single-phase and multiphase flow;
— pressure, temperature, phase fraction, velocity, etc., and their distribution in space and time; and
— distribution of fluid phase compositions in both time and space.
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TECHNICAL REPORT ISO/TR 27925:2023(E)
Carbon dioxide capture, transportation and geological
storage — Cross cutting issues — Flow assurance
1 Scope
This document describes and explains the physical and chemical phenomena, and the technical issues
associated with flow assurance in the various components of a carbon dioxide capture and storage
(CCS) system and provides information on how to achieve and manage flow assurance. The gaps in
technical knowledge, limitations of the tools available and preventative and corrective measures that
can be taken are also described.
This document addresses flow assurance of CO streams in a CCS project, from CO capture via
2 2
transport by pipeline and injection well through to geological storage. It does not specifically address
upstream issues associated with CO sources and capture, although flow assurance will inform CO
2 2
capture design and operation, for example, on constraints on the presence of impurities in CO streams,
2
as there are too many different capture technologies to be treated in detail in this document.
Vessel transport and buffer storage that are considered in integrated CCS projects under development,
are not covered in this document. Flow of material in the supply chain of a CO source, even if delivered
2
by a pipeline (e.g. blue hydrogen generation), and flow of gas streams within facilities generating and
feeding these into a capture facility can impact flow assurance in CCS projects and networks. These are
out of the scope of this document as well.
This document also examines the impact of impurities on the phase behaviour and physical properties
of the CO stream which in turn can ultimately affect the continuous supply of the CO stream from the
2 2
capture plant, through the transportation system and into the geological reservoir via injection wells.
Flow of fluids in oil reservoirs for the purpose of enhanced oil recovery is not within the scope of this
document.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 27917, Carbon dioxide capture, transportation and geological storage — Vocabulary — Cross cutting
terms
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 27917 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
carbon dioxide capture and storage network
CCS network
connections of multiple CO sources and storage sites
2
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ISO/TR 27925:2023(E)
3.2
carbon dioxide capture and storage project
CCS project
either single capture-transportation-storage systems or multiple systems (networks) consisting of CO
2
capture systems, CO transportation systems, and CO geological storage systems
2 2
Note 1 to entry: In this document, the facilities generating a CO stream are included in the considerations of
2
flow assurance, as part of any decision or event at these facilities affecting the amount of CO stream sent to the
2
capture system, and will impact flow assurance within the CCS project.
Note 2 to entry: For more information on
— CO capture systems, see ISO/TR 27912,
2
— CO transportation systems, see ISO 27913, and
2
— CO geological storage systems, see ISO 27914.
2
3.3
carbon dioxide capture and storage system
CCS system
combination of the capture, transportation and storage components considered as a single entity
3.4
component
assemblage of technical or geotechnical installations and natural features of subsurface geological
systems that are separate in terms of physical space, technical disciplines, industrial practice and
dominating physico-chemical processes
3.5
flow regime
type of flow pattern developed by fluid flowing through pipes
Note 1 to entry: Flow regimes depend on pressure and temperature dependent fluid properties, the diameter
of the pipe, flow rates, fractions of each phase and the inclination of the pipe. Flow regimes can change with
distance along a pipeline. In single phase flow, the regimes laminar and turbulent flow are distinguished.
3.6
hydraulic capacity
maximum flow rate achievable in a system for a given pressure loss
4 Abbreviated terms
BHP bottom hole pressure
BHT bottom hole temperature
CCS carbon dioxide capture and stor
...