Assessment of CO2 geological storage capacity of saline aquifers under the North Sea

doi:10.1016/j.ijggc.2021.103463

International Journal of Greenhouse Gas Control

Volume 111, October 2021, 103463

https://doi.org/10.1016/j.ijggc.2021.103463 Get rights and content

Highlights

•
Conducted a comprehensive analysis of 441 potential CO₂ storage sites under north sea.
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Extended application of pressure-based approach for storage capacity estimation.
•
Comparison of CO₂ emissions with available capacity for each country considered.
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Establishment of an open source database with geophysical characteristics of oil & gas fields and saline aquifers considered.

Abstract

In this study, potential storage sites in the subsurface of the North Sea are analyzed to estimate the available CO₂ storage capacity. In total 441 sites in five countries (United Kingdom, Denmark, Norway, Netherlands and Germany) are studied in terms of geophysical characteristics and potential capacity. Instead of a simple volume-based approach that tends to over-estimate capacity, we consider storage limited by the time-dependent pressure increase in each injection well. We used literature data to estimate the geological and physical properties of the storage formations. The study confirmed a tremendous potential for CO₂ storage approaching 440 Gt with a possible injection rate of 22 Gt yr⁻¹. The United Kingdom can potentially store more than 230 Gt of CO₂ over 30 years, a value 20 times higher than its current emissions, while the same scales apply for the Netherlands with 147 Gt CO₂ potential. The thirteen oil and gas fields examined in Denmark are able to store around 4 Gt of CO₂ over three decades at a rate of 127 Mt yr⁻¹ covering more than twice the current emissions, while Norway can store 48 Gt from just 10 large saline aquifers. Despite the potential uncertainties in the data, there is sufficient capacity for CO₂ storage to play a significant role in Europe to avert a temperature increase of more than 1.5 °C this century.

Graphical abstract

Introduction

According to the Intergovernmental Panel for Climate Change (IPCC, 2021), human activities are estimated to have caused approximately 1.09 [0.95 to 1.20] °C of global warming above pre-industrial levels. This amount is expected to reach 1.5 [1.2 to 1.7] °C between 2021 and 2040 (SSP1), with existing growth rates. Current dependence on fossil fuels and their unconstrained extraction are expected to consume the available carbon budget within the next decade further contributing to global warming (Karvounis and Blunt, 2021). This temperature increase is expected to lead to extreme natural phenomena including extensive droughts, hot days and cold nights near the equator and substantial sea level rise (Masson et al. 2018, Masson-Delmotte et al., 2021). According to the Shared Socioeconomic Pathways (Riahi et al., 2017) an increase of two billion in the population is almost inevitable over the next few decades. In the event of such a scenario, demand for energy and other resources is projected to increase with a consequent increase in greenhouse gas emissions up until 2060 at least.

Carbon capture and Storage (CCS) is expected to be one of the game changers in efforts to combat climate change. Even in the most pessimistic scenarios for the growth of emissions (SSP5, SSP2), CCS plays a significant role with more than 5 Gt per year to be deposited underground in the next 50 years. Since 2009, the European Union has set guidelines for the implementation of large-scale CCS initiatives within its territory, by publishing the directive for carbon capture and storage (2009/31/EC, 2009), urging the 27 member nations to initiate studies and evaluate their storage capacity potential. But what is the potential storage capacity?

For the subsurface, Fang et al. (2010) proposed a set of basic characteristics in saline aquifers that need to be examined prior to injection that will assist with a capacity estimation. These include potential faults in the rock (Alonso et al., 2012), cap rock integrity, and other geological assessments to provide information about CO₂ migration, the size of the reservoir, the associated depths, as well as several geophysical characteristics such as the porosity and permeability of the rock. Other important properties to be acquired include fluid properties encompassing brine salinity, water and CO₂ viscosity and density that affect its solubility. Schulze et al. (2009) and Heitmann et al. (2012) demonstrated that Europe's emissions are concentrated in the North, mainly due to industrial activity. Therefore, North Sea storage sites have been traditionally investigated (Chadwick et al., 2004; Holloway et al., 2006), in terms of geophysical characteristics (Taylor et al., 1994, 2015). Kolster et al. (2018), used a commercial software to calculate the sensitivity of CO₂ storage by varying the injection rate. The Bunter sandstone formation of North Sea was used, while locations of low and medium permeability were chosen as injection sites. Agada et al. (2017) studied the impact of the number of injection sites and injection rate on ultimate CO₂ storage. Again, the great Bunter sandstone formation in UK's territory of North Sea was selected. They showed that depth plays a vital role in overall capacity, as it is associated with pressure limits allowed at the storage site. Anthonsen et al. (2014) studied storage in the Baltic Sea, while Heinemann et al. (2012) also focused on Bunter sandstone formations, Bentham (2006) considered the Southern North Sea, while Van der Meer et al. (2009) studied several saline aquifers in the Dutch territory of the North Sea. Other studies, such as Aminu and Manovic, (2020) include the effects of impurities in CO₂ streams (NO₂, SO₂) on reservoir performance. Injectivity is affected only during the early stages of injection into the reservoir.

In this paper, a first order assessment of CO₂ geological storage under the North Sea is conducted. While, as outlined above, other studies have been performed during the past decade, these have been country focused or limited to certain geological formations. In contrast, our study examines a total of 441 potential fields categorized according to their suitability for carbon sequestration. These sites include oil and gas fields, depleted or under production, as well as saline aquifers, belonging to the territorial sea of the United Kingdom, Norway, Denmark, the Netherlands and Germany. Where possible we compare with previous storage estimates in the literature.

Section snippets

Methodology

The tool used to estimate storage capacity is the CO2BLOCK, open source, software developed by De Simone and Krevor (2021) (available here) that receives as input the geophysical characteristics of specific fields to estimate the capacity as a function of the number of injection wells. The model considers only physical processes occurring in subsurface; no chemical processes are considered. The software uses a sophisticated analytical model of pressure dissipation – which has been validated

Results

In this section, the North Sea CO₂ storage capacity potential is reported, following the methodology described previously, for territories belonging to the United Kingdom (UK), Denmark, Norway, the Netherlands and Germany. Several offshore oil and gas fields were considered as well as saline aquifers. The fields studied in every country were chosen dependent on data availability. For the United Kingdom, 82 oil and gas fields were considered (some of them depleted or close to depletion, while

Conclusions

Carbon capture and storage is a necessary mitigation strategy to avoid dangerous climate change. Extensive CO₂ capture and injection into the subsurface prevents its release into the atmosphere and stores it permanently for several thousand years. In Europe, the greatest part of its carbon dioxide emissions is concentrated in the boundary areas/regions of the North Sea and are a product of substantial industrial activity in the countries of the north.

This study is a comprehensive analysis of

CRediT authorship contribution statement

Panagiotis Karvounis: Software, Writing – original draft, Investigation, Methodology, Data curation. Martin J. Blunt: Conceptualization, Writing – review & editing, Supervision, Methodology, Data curation.

Declaration of Competing Interest

The authors declare no conflict of interest.

Acknowledgements

We would like to thank Drs. Sam Krevor and Silvia de Simone for help with using CO2BLOCK.

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Assessment of CO2 geological storage capacity of saline aquifers under the North Sea

Highlights

Abstract

Graphical abstract

Introduction

Section snippets

Methodology

Results

Conclusions

CRediT authorship contribution statement

Declaration of Competing Interest

Acknowledgements

Int. J. Greenhouse Gas Control

Eng. Geol.

Int. J. Greenhouse Gas Control

Energy Procedia

Energy

Int. J. Greenhouse Gas Control

Energy Procedia

Int. J. Greenhouse Gas Control

Int. J. Greenhouse Gas Control

Global Environ. Change

Int. J. Greenhouse Gas Control

Int. J. Greenhouse Gas Control

Energy Porcedia

Mar. Pet Geol.

Energy Procedia

Thermophysical properties of carbon dioxide along the liquid vapor equilibrium lines

J. Eng. Phys.

A modelling study to evaluate the effect of impure CO2 on reservoir performance in a sandstone saline aquifer

Heliyion

Screening for CO2 storage sites in Southeast North Sea and Southwest Baltic Sea

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An Assessment of Carbon Sequestration Potential in the UK – Southern North Sea case Study

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