Limiting the average global temperature rise to 2 °C by 2100 will require billions of tons of carbon dioxide (CO2) to be permanently stored in deep geological formations. We have been involved in this issue for many years and now are stepping up our efforts to deliver methods and technologies to guarantee that large-scale CO2 storage projects can be operated completely safely.
Total has a longstanding commitment to CO2 storage
Geological storage of CO2 aims at playing a key role in attaining carbon neutrality during the second half of this century. This is not a new topic for Total, and we have built up solid expertise in this field.
By the 1990s, Total’s E&P Branch had undertaken research programs aimed at separating or capturing acid gases (CO2 or H2S) for subsequent reinjection into deep reservoirs. These programs had a dual goal: (1) to allow us to exploit gas fields containing high levels of acid gases while minimizing our emissions and downsizing our sulfur processing requirements, and (2) to capture the CO2 emissions from industrial facilities for injection underground rather than venting to the atmosphere.
At the same period, Total was involved in the first industrial implementation of geological CO2 storage on the Sleipner field in the North Sea (Norwegian sector). Our expertise served especially for characterizing the formation, into which 0.85 million tons of CO2 have been injected each year since 1996, as well as for monitoring the storage reservoir. Total is also a partner in the Snøhvit LNG project (Barents Sea) where more than 4 million tons of CO2, extracted from the natural gas stream ahead of liquefaction, have been stored underground since 2008.
In 2006, Total’s commitment to curb greenhouse gas emissions reached a new level with the launch of our industrial pilot demonstrating the CO2 capture, transport and storage chain in the Lacq basin (France) – a first in Europe!
Leading-edge expertise in CO2 storage
The Lacq pilot was a complete success. In three years (from January 2010 to March 2013), more than 51,000 tons of CO2 were captured using the oxyfuel combustion process on a gas-fueled boiler for injection at a depth of 4,500 m into the Rousse reservoir, a depleted natural gas deposit produced from 1972 through 2008. The project aimed at formalizing a validation process for CO2 storage that would include methods and techniques for selecting, qualifying and monitoring a storage site.
Injecting large volumes of CO2 into a geologic reservoir for long-term storage requires specific geoscientific approaches to guarantee the storage integrity – and therefore the containment of the CO2 – for the very long term. In preparation for this demonstration pilot:
- Geologic and reservoir models of the target reservoir were used to reproduce its pressure response during its producing period and extrapolate the pressure rise and migration of the CO2 in the reservoir during the injection phase;
- Geomechanical and geochemical studies were performed to demonstrate that the pressure level at the end of the injection phase would not damage the formation or cap rock, and confirmed the absence of any detrimental chemical interactions between the CO2 and the rock. These conclusions were supported by models of the long-term behavior of the CO2 in the reservoir.
Our state-of-the-art expertise in measuring the mechanical properties of cement were also of value to verify the integrity of the injection well in the context of CO2. In fact, the investigations on the mechanisms of CO2 interaction with well cements, which we conducted jointly with partners in academic research, demonstrated that the mechanical properties of the cement actually improve upon contact with the CO2, thereby reinforcing this well barrier.
A monitoring network installed at the site (to monitor injection, reservoir behavior, and microseismic activity on multiple scales) confirmed that the reservoir was behaving in line with our forecasts. A concurrent, and ambitious environmental monitoring program consisting of water quality monitoring (of both surface and groundwater), ecosystem monitoring (flora and fauna) and soil gas monitoring highlighted the most effective techniques; it also confirmed the imperviousness of the storage reservoir.
An Investment on Par With The Stakes of Climate Change
Today, we are stepping up our efforts to make sure that the full potential of existing CO2 capture, utilization and storage techniques (CCUS) is tapped in connection with the so-called 2 °C scenario of the International Energy Agency. Total’s participation in the Northern Lights project (Norway) alongside Equinor (formerly Statoil) and Shell reflects our determination to accelerate the deployment of these technologies. Northern Lights is the world’s first commercial project for the storage of industry-generated CO2. It is designed to store nearly 40 million tons of CO2 over a 25-year period on the Norwegian continental shelf. Its aim is to establish a viable, commercial and replicable model of CCUS as a springboard for other large-scale projects around the world.
Another example of our proactive approach is the extensive R&D effort we are devoting to CCUS, which is should ultimately account for 10% of Total’s aggregate R&D spending. Our teams are mobilized to come up with solutions that will ensure the complete safety of operation of large-scale CO2 storage projects. They are also working on reducing the uncertainties surrounding global storage capacity for this greenhouse gas. We are working on this topic as part of the Oil and Gas Climate Initiative, an international industry consortium. Total had an active role in developing the first version of the CO2 Storage Resources Management System (SRMS), validated by the Society of Petroleum Engineers (SPE) and released in 2017. The SRMS aims to establish a consistent methodology for estimating underground CO2 storage capacities. There is a lot at stake here, because no massive deployment of CO2 storage can happen unless we first have access to consistent and reliable assessment data on the planet’s potential storage resources, classifying them according to a confidence level, in analogy to industry best practices with oil and gas reserves.
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