Intelligent tracers in a sustainable energy system

The E&P industry is under increasing scrutiny as demands are growing for a more sustainable energy system.

By Gunnar Hviding June 2, 2022
Courtesy: Resman

The E&P industry is under increasing scrutiny as demands are growing for a more sustainable energy system. The global Greenhouse Gas Emissions (GHG) are approximately 40 billion tonnes, of which 18.2 Gt or 46% comes from extraction and use of oil & gas, according to Intergovernmental Panel on Climate Change (IPCC) and International Energy Agency (IEA).

The initial response from the E&P industry has been to improve on its’ owned emissions from production, which is covered by Scope 1 and 2 in the Paris Accord. The industry is now turning to the emissions from the use of hydrocarbons, which is covered by Scope 3, and we now see significant growth in projects for carbon capture and storage (CCS).

In 2019 there were approx. 20 projects with a storage rate of 40 million tons per year. In 2021, the number of projects have risen to around 65. The IEA estimate that in order to limit temperature rise to 1.8 degrees, the storage capacity has to increase to 2.8 billion tons per year by 2050, taking the total number of projects to 2,000.

Tracer technology is one of the technologies which can help operators achieve these objectives through use of risk-free methods to monitor and optimize CO2 injection in existing assets, either for storage, pressure support or EOR operations. Central to all these solutions is to track the flow pattern of the CO2 injected and avoid it reaching the producing wells, thereby storing the CO2 safely and potentially using CO2 to increase production efficiency – a win-win solution for the industry.

Courtesy: Resman

Courtesy: Resman

What is tracer technology?

The underlying principle of chemical tracers is the release of specific molecules which follows the liquid or gas flow in the reservoir. As such, if a tracer is detected then there is flow communication between injection point and sampling point.

The tracers can either be installed in the well completion or pumped into an injector well or producing well, dependent on which data the operator seeks. In a CCS application, the operator wishes to ensure that the CO2 injection is going as planned, and avoid the CO2 reaching the producing wells where it will have to be separated out and thus reducing the value of the end product.

Increased profitability through reducing the carbon footprint

Carbon dioxide flooding is an EOR method, which has been around for decades. In the early days, some operators tested this method with CO2 which had to be manufactured. Our prediction is that CO2 will be a very viable ‘energy transition method’, as it allows operators to deposit CO2 and at the same time pay for the clean-up cost with increased productivity.

The principle behind CO2 flooding is to reduce interfacial tension and ultimately obtain miscibility between CO2 and oil and thereby  “washing” the oil out of the reservoir. Successful operations demand a thorough understand of reservoir characteristics and tracer technology is a powerful method to monitor flow behavior and to optimize field operation.

Courtesy: Resman

Courtesy: Resman

CO2 storage for pressure support

CO2 may be injected to maintain pressure in reservoirs still under oil/gas production. It is crucial that this CO2 remain stored in the reservoir and not enter the reservoir volumes still under production. To monitor that CO2 is safely stored, Resman can trace the CO2 injectors with different chemical tracers and thereby measure potential leaks from the storage into the production zone.

Use of tracers in for CO2 storage

Resman’s tracers and methodologies are compatible with CO2 – and at the same time unique and distinguishable from the CO2 itself or other molecules present in the sub-surface.

Using Resman’s methodology, an extreme detectability for tracer is possible. Therefore, a small tracer amount is sufficient to monitor large scale subsurface flow patterns. As such, Resman’s tracer methodology is well-suited to monitor the state and possible movements of CO2 in CCS projects. The tracers are therefore a valuable aid in CCS projects by acting as an assurance that CO2 is contained in the desired location sub-surface. In the past, our technology has been used to monitor and study movements in CCS projects in Algeria, the Netherlands and Norway and with other CCS projects being planned worldwide.

Non-toxic and non-radio active

Tracer concentration is analyzed in parts-per-trillion concentrations, and as such, very little organic compounds are used with a small carbon footprint. The Resman tracers do not contain poisonous substances which may pollute the environment and pose a danger for operators, such as Cadmium or radioactive isotopes.

The road to a sustainable future

The development of tracer technology is an important piece of the puzzle when it comes to storing CO2, and even utilizing the CO2 to enhance productivity. Tracers allow the operators to track the CO2 injection and avoid intrusion into production wells, thereby ensuring a safe storage and potentially increase economic returns in the project.

Original content can be found at Oil and Gas Engineering.

Author Bio: Gunnar Hviding, chairman & CEO, Resman AS