Combining carbon capture with enhanced oil recovery in Trinidad and Tobago

GEOLOGICAL SOCIETY

For decades there have been ideas, proposals, plans and discussions to capture CO2 from TT’s industrial plants (mainly at Pt Lisas), transport them to depleted or heavy oil fields, and inject the CO2 into the reservoirs, thereby producing additional oil due to the reduction of viscosity of the oil. The added benefit is that a large proportion of that CO2 remains sequestered in the ground, instead of being vented to the atmosphere by the industrial plants. To date, none of these projects have been realised on a commercial scale. There is, however, renewed interest in the last few years from local and international companies and institutions. The GSTT is in strong support of carbon capture research and projects being at the forefront of the country’s medium- to long-term plans.

TT is on a journey to reduce its greenhouse gas emissions by 15 per cent by 2030. Our small twin island state is 0.02 per cent of the world’s population yet accounts for 0.1 per cent of global CO2 emissions. In fact, Trinidad has one of the highest carbon dioxide emissions per capita in South America which is estimated at 23.6 tonnes per person (2020) or 36.1 million tonnes annually. To achieve our Paris Agreement target by 2030 requires a significant commitment and the use of emerging and other clean energy technologies. One such technology is carbon capture utilisation and storage (CCUS).

CCUS refers to a suite of technologies which enables carbon dioxide in the atmosphere to be captured at the site of emissions such as power plants, refineries and other industrial sites and transported to a location where it can then be utilised in the manufacture or other products or stored underground in geological formations. Capturing carbon dioxide reduces the amount of this greenhouse gas in the atmosphere and brings us one step further along the journey of global decarbonisation.

In countries with oil production, CO2 which is injected in geological formations can have the benefit of boosting or supporting oil production. This is known as enhanced oil recovery (EOR). In this application 50-60 per cent of the CO2 is produced with the oil and the remainder if permanently trapped in the reservoir. CO2 can also be injected into reservoirs which are no longer on production (depleted reservoirs) and saline (salt water) aquifers for sequestration. As of 2021, the global carbon capture capacity was estimated at 40 million tonnes per year across 26 operational CCS facilities. Of these operational facilities, 12 can be found in the US. The US alone has an estimated storage capacity ranging from 2.6 to 22 trillion tonnes. Each year, the US injects approximately 62 million tonnes of CO2 underground to help recover oil and gas resources.

In 2022, bp signed on to aid TT’s energy transition through support for its first carbon capture storage (CCS) mapping project to determine underground sites that can be used to store captured carbon dioxide. These include depleted hydrocarbon reservoirs both onshore and offshore. Apart from funding, bp’s support for the project includes technical support and access to reservoir data. BP has committed $340,000 to the CCS storage Atlas project which is being led by UWI and UTT.

Currently, there are no CCS facilities in the Caribbean and the development of this atlas of CCS sites in TT could position this country as a leader in the region all the while assisting us to achieve our emissions goals. Projects of this type are foundational to the feasibility of CCS as part of the solution to significantly reducing our carbon emissions. CCS works hand-in-hand with other low carbon industries such as blue hydrogen.

There are several considerations which could encumber the use of CCS in Trinidad. One of these is the cost of CCUS facilities. Retrofitting existing facilities can be capital intensive, as is building new CCUS facilities. This is particularly true where energy costs are high. This should be weighed against the cost of alternative decarbonisation options as well as the future cost of carbon intensive products in an increasingly competitive world. Another significant consideration is leakage from geological formations into the atmosphere which would reverse the intended emissions savings and possibly lead to extended environmental degradation. Loss of containment is particularly relevant in storage sites with many old wells and infrastructure which may not have sufficient integrity to contain the CO2. Before any sequestration is started in underground reservoirs, all existing infrastructure should be properly remediated or permanently abandoned to ensure no leakage via these channels. Yet another consideration is the regulatory framework of our country. In our current economy, CCUS is not as commercially lucrative as other industries. Supportive legislation and frameworks (especially for tax incentives) are essential to encouraging enterprises to adopt and/or incorporate carbon capture into their operations.

TT is blessed to have over 160 years of petroleum history. We have seen the transition of this economy from oil production to gas production to LNG. Our geoscientists, engineers, legal and financial minds are world class and as we continue to evolve along the energy journey, we can leverage the deep technical knowledge in this space and apply it to this challenge. Is CCS the magic bullet to help achieve our Paris goals? Simply put, No. Can we employ CCS to help us partially attain our emissions targets? Optimistically, Maybe.

At the energy conference in January, the Ministry of Energy revealed preliminary carbon storage estimates of fields which were within scope of the assessment. In the Forest Reserve and Palo Seco fields there is an estimated theoretical storage capacity of 9.5mt (metric tonnes) of CO2 spread across four reservoirs. In the Southern Basin, there is an estimated 101.1mt of CO2 of theoretical storage capacity across onshore and offshore fields in the study area. Another working group was tasked with evaluating an area for CO2 EOR project. The Forest Reserve field was selected as this area shows the most potential for success and is known to have past and current successful EOR projects. At present, further evaluation is being conducted to determine a suitable fault block within the Forest Reserve field.

What does this mean? Preliminary estimations of carbon storage capacity are promising, and a more balanced view should emerge when the assessment is complete. Should we assess various decarbonization options? Emphatically, Yes. It behoves us to innovate and embrace clean energy technologies to help us achieve the low carbon future we envision for ourselves.

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