THERMAL HEAVY OIL RECOVERY (THOR)
Introducing THOR, an innovative downhole technology which will revolutionise Thermal Heavy Oil Recovery and:
■ Bring Thermal EOR to previously discounted wells
■ Inject heat into the well bore at source
■ Increase production rates
■ Maximise flow assurance
■ Increase recoverable reserves
■ Increase customer shareholder value
THOR is suitable for deployment in wells with the specific goal of utilising thermal properties to enhance production while limiting the build-up of waxes, scales etc. The devices have the ability to heat liquids at source as opposed to traditional methods where this is typically done topside and pumped to the location where inevitably large energy losses occur.
WHY HEAVY OIL?
■ The UK’s OGA predicts that by 2025 42% of daily North Sea production will be heavy oil.
■ Only 30% of remaining oil is considered “light oil” while the remaining 70% are considered “heavy oils”
■ The International Energy Agency stated that increasing recovery of these heavier crudes could unlock approximately 300 billion barrels
■ There are approximately 7 billion barrels of known heavy oil to be developed in the UKCS alone
WHY THERMAL EOR?
■ Thermal methods of enhanced oil recovery entail the application of heat to the oil well. This acts to lower the viscosity of the oil and thus increase the mobility ratio.
■ Thermal EOR processes have the greatest certainty of success and application in about 70% of the EOR market globally.
■ Recovery rates up to double have been seen but generally increases of c. 20%-50% are readily achievable using thermal EOR.
■ Thermal methods dominate the EOR market, accounting for just over 2 million barrels per day in 2014, which is 63.8 percent of global EOR production.
■ In 2015 global thermal EOR spending was $23.9bn.
CONVENTIONAL THERMAL EOR
■ Power restrictions offshore keep thermal injection rates low (around 250 bpd per injector)
■ If injecting 250 bpd from topside, even with insulated pipe, losses to wellbore would give cold water at reservoir
■ Heat is lost 250% faster to seawater than sandstone
■ Thermal injection of up to 3000 bpd per well.
■ Very little heat loss as heating takes place downhole near the reservoir.
■ Significantly smaller footprint than traditional thermal/steam generation.
■ Green power sources could be utilised for THOR.
■ THOR Temperature ranges negate the requirement for high temperature completions and the use of thermal cement.
■ Could be retrofitted to fields not designed for thermal EOR to extend field life
■ Less sensitive to water quality than current thermal EOR methods
■ Has applications in both injection and production wells
■ Could be used for combined thermal and chemical injection operations
THOR: INITIAL GEOSCIENTIFIC MODELLING
UKCS Paleocene Trubidite Reservoir Modelling
■ Numerous Cavitas units injecting 250 bpd at 120oC
■ Increases reservoir temperature from 42oC to 116oC
■ Reduce viscosity from 200cp to 9cp (like light oil)
■ Increases ultimate recovery from 17 to 20%
■ 300 mbbl to 360 mbbl recoverable of a 1.9 bbbl STOIIP field
■ @ $30 = Extra $1.8 billion over life of field (30 years)
These figures were calculated using publically available information relating to a real UKCS heavy oil development that is currently in the process of being brought on-stream.
The planned number of injector wells across the reservoir was 37. Assuming a THOR device was present in each injector well producing heated fluid at 120oC would increase the reservoir temperature to 116oC.
This increase in temperature would reduce the viscosity from 67cp to 7cp.
This projected reduction in oil viscosity would increase the recovery factor from 16-17% (claimed as 300mbbl) of the slightly under 2 billion in place within the reservoir to 20% (adding 3% or 4%) to 360mbbl.
If these extra 60 mbbl were sold at $30/bbl this would return an extra $1.8 billion over the projected field life of 30 years.