A novel power generation technology from Maersk Oil is set to provide new commercial solutions for enhanced oil recovery and unlocking stranded gas fields, writes Bob Alford
OUR new TriGen technology is derived from the space industry and involves burning gas together with pure oxygen to produce power, water and carbon dioxide. The resulting high purity CO2 is captured – making the power generation emission-free – and can be transported to fields for enhanced oil or gas recovery (EOR/EGR).
This technology can provide synergy across the energy industry to create value for both resource owners and energy producers. The global energy business has traditionally been separated into upstream, downstream and power generation activities.
This provided the right business focus for resource owners and power producers and made perfect sense with current oil extraction and power generation technology. With TriGen, however, linking power generation back to upstream oil and gas activities, a zero emission solution across the energy value chain becomes possible as all of its outputs are useful commodities.
It was the EOR application that first caught the eye of Maersk Oil, as we had already started to study whether we could use CO2 to enhance recovery from our own mature oil fields, and was seeking low cost sources of the gas.
However, we soon realised that the technology’s multi-stream output, including its ability to burn CO2-contaminated gas as fuel without any pre-treatment, actually gave it access a number of business opportunities around the world.
We are currently exploring opportunities in the Middle East and South-East Asia that have different value chains and benefits, yet both can now be made commercial from the implementation of the TriGen technology.
In the Middle East, at Maersk Oil we are investigating whether TriGen’s low cost CO2 can enable EOR projects. Gulf countries in particular have increasingly focused on clean energy, while many of its oil and gas reservoirs are well-suited to CO2-EOR and nitrogen or CO2 based EGR.
Here, gas would be burned to produce clean power and water for households. Nitrogen, a by-product from the production of pure oxygen, and CO2 would be supplied to oil fields – nitrogen to maintain the pressure in depleting reservoirs and CO2 as the EOR agent coaxing out oil that would otherwise not be recovered.
In TriGen’s oxyfuel combustion process, fuel is mixed with pure oxygen and burned at pressure in excess of 100 bar and temperatures over 2200 degrees Celsius.
TriGen gets its pure oxygen from a standard Air Separation Unit that compresses and cools atmospheric air until oxygen and nitrogen are separated by distillation.
The hot combustion gases that are produced (only steam and CO2) are expanded in a turbine that drives a generator while the pure water and resulting high quality CO2 are separated.
The generated power becomes emissionfree as the ‘reservoir ready’ CO2 is transported to oil and gas fields where it is injected deep underground for Enhanced Oil or Gas Recovery (EOR/EGR).
Traditionally, CO2-based EOR has only been feasible in areas with large sources of natural CO2 – chiefly in the United States. But the ability to produce pure CO2 as a by-product of a commercial power generating venture now makes CO2-based EOR attractive in regions such as the Middle East, which has limited sources of natural CO2.
Additionally, as TriGen produces water, it can be placed in remote locations where water is not readily available. This water can be used for domestic purposes or irrigation.
In the oil field, the low salinity water is beneficial for improving recovery in water floods.
The technology provides us with a competitive advantage in the Gulf region, as it offers both the benefit of clean power and lowcost CO2 to increase recovery potential. The technology also complements our current work and studies on CO2-based EOR in Denmark and Qatar, enabling us to offer integrated field development solutions in this area.
In South East Asia, the value chain starts at a different point – at world class gas fields that lie undeveloped because they are contaminated by CO2. Such stranded gas fields could now potentially be produced economically because the TriGen technology can burn gas contaminated with up to 90 per cent of CO2 without requiring any costly pretreatment for CO2 removal.
We would be unlocking enormous value to the states that have been sitting on these fields, unable to produce them commercially. Although it is early days yet, with technical and commercial challenges to overcome, these are just the kind of projects that affirm Maersk Oil’s pioneering approach to business.
We launched the project two years ago and in January 2011 announced the acquisition of rights to the combustion technology from US-based Clean Energy Systems (CES).
CES, in collaboration with Maersk Oil, Siemens and the US Department of Energy, is maturing the technology. Derived from rocket science, where pure oxygen is used to burn fuel, CES has proven the technology on a smaller scale over the last15 years. Siemens is currently converting a conventional gas/air turbine to a gas/oxygen turbine for a commercial power plant project in California using the TriGen technology.
The converted turbine – approximately the size of a Maersk shipping container – will be hooked up to a power grid in North Los Angeles next year and has the capacity to deliver 150 megawatts of electricity – enough to provide energy to over 100,000 homes.
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