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Direct Contact Steam Generation

01

How It Works

Process, EOR Mechanisms, and Surface Equipment

Simultaneous Steam and Flue Gas Injection

GERI’s DCSG Co-Injector combusts pressurized air and natural gas in direct contact with water, creating a combined product of high-pressure steam (or hot water) and flue gas (mainly CO2 and N2), which are then co-injected downhole.

DCSG Block Flow

Steam mode (Maximums)

Heat rate: 10 GJ/hr (9.5 MMBtu/hr)
Temperature: 248°C (478°F)
Pressure: 7,000 kPa (1,015 psi)
Steam Rate: 90 m3/d (565 bbl/d) CWE at 80% quality
Non-condensable gas injection rate: 54 e3m3/d (1,920 mcf/d)
Non-condensable gas composition (mol): Approximately 88% N2, 12% CO2, trace others

Hot water Mode (Maximums)

Heat rate: 5 GJ/hr (4.7 MMBtu)
Temperature: 95°C (203°F)
Pressure: 7,000 kPa (1,015 psi)
Hot Water Rate: 400 m3/d (2,500 bbl/d)
Non-condensable gas injection rate: 29 e3m3/d (1,024 mcfd)
Non-condensable gas composition (mol): Approximately 88% N2, 12% CO2, trace others

Multiple Sub-Surface EOR Mechanisms

GERI’s Direct Contact Steam Generation (DCSG) Co-Injection technology is designed to improve heavy-oil recovery by combining multiple, proven enhanced oil recovery (EOR) mechanisms that address both the properties of the oil and the reservoir. It restores pressure and increases oil displacement and recovery by:
  • Reducing oil viscosity by adding heat
  • Charging and/or maintaining pressure in reservoir by injecting non-condensable gas
  • Reducing heat loss to the overburden by creating an insulating blanket of non-condensable flue gas at the top of the reservoir
  • Slightly reducing viscosity and swelling the oil by dissolving CO2 (in colder oil)
  • Improving sweep efficiency with simultaneous gas override and water underride sweep (not applicable in steam assisted gravity drainage (SAGD)

Portable and Modular Surface Equipment

GERI’s portable DCSG Co-Injector is supported by GERI-owned process modules (air and fuel compressors, electrical generators, tanks). These are supplied by GERI but, alternatively, air and fuel compression and electrical requirements can be provided by the customer if preferred.

The DCSG equipment takes approximately a week to set up and only a few days to rig out, depending on site-specific factors.

Surface Equipment
Setting up the equipment on site
Setting up the equipment on site
It typically takes 3-4 days to complete setup, including rigging
It typically takes 3-4 days to complete setup, including rigging
Setting up the equipment on site
Setting up the equipment on site
Setting up the equipment on site
Setting up the equipment on site
It takes 14 loads to move all the equipment to site
It takes 14 loads to move all the equipment to site
Air compressor building leaving Lloydminster
Air compressor building leaving Lloydminster
Loading the DCSG Co-Injector building
Loading the DCSG Co-Injector building

Water Treatment Unit

GERI owns and operates an ion exchange water-softening and chemical injection plant. Using fresh water, it’s capable of producing ample boiler quality water for our DCSG co-injector, reducing costs, simplifying logistics, and broadening our operational range. We offer our Water Treatment Unit to provide boiler quality water as an additional service, if required.

Pilot Results

GERI has been on a multi-year journey from bench-scale development to a working commercial model. Below are average results from GERI’s projects on our own wells and for customers.

The project well was initially put on production in 1996 and eventually suspended in 2013 due to a decline in oil production (as a result of the reservoir depleting), rendering the well un-economic. Less than 10% of the original oil in place (OOIP) was recovered during this initial (primary) production phase due to the high viscosity of heavy oil and the loss of the reservoir’s drive mechanism. In July 2020, GERI was moved onto the site to conduct a well stimulation.

GERI injected at a nominal heat rate of 8 GJ/hr for 20 days with only 9% downtime for a cumulative steam volume of 1,470 m3
Production Chart

(at ~80% quality). The well was put on production and produced for approximately six months before being shut in. The cumulative
oil produced (including incremental oil from offset producers) was 908 m3, meaning this project achieved a cumulative steam-to-oil ratio (SOR) of 1.6.

The cumulative CO2 volume injected was 96 e3m3, and 43 e3m3 was produced, meaning 55% of the CO2 coming from steam generation was retained in the reservoir.

co₂ injected and produced

The project well was initially put on production in 2012 and eventually suspended in 2014 due to a decline in oil production (primarily as a result of the reservoir depleting), rendering the well uneconomic. Less than 1% of the original oil in place was recovered during this initial (primary) production phase due to the high viscosity of heavy oil and the loss of the reservoir’s drive mechanism. In Q3 2017, GERI was moved onto the site to conduct a well stimulation.

GERI injected at a nominal heat rate of 4.5 GJ/hr for 20 days with only 5% unscheduled downtime, for a cumulative steam

Production Chart
volume of 1,144 m³ (at ~65% quality). The well was put on production and produced for approximately 13 months before being shut in due to economic cut-off. The cumulative oil produced was 664 m³, meaning this project achieved a cumulative steam-to-oil ratio (SOR) of 1.7, excluding potential increased productions from offset wells. The cumulative CO₂ volume injected was 61 e³m³, and 18 e³m³ was produced, meaning 70% of the CO₂ coming from steam generation was retained in the reservoir.
co₂ injected and produced

02

Environmental Benefits

GHG Emissions

In thermal heavy-oil recovery, combustion exhaust (flue) gas is emitted to atmosphere when generating high-pressure steam. By contrast, GERI co-injects steam and the associated combustion exhaust gases downhole, mitigating the atmospheric release of greenhouse gases (GHG) and permanently storing some of the CO2 in the reservoir.

OTSG - THE CONVENTIONAL WAY
DCSG - THE GERI WAY
Our co-injection technology reduces carbon intensity by up to 67% compared to conventional OTSG* and, in past cyclic stimulation pilots, up to 70% of the CO2 injected has remained downhole after one injection and production cycle.

*Per barrel of oil produced. Reservoir and electricity-source dependent. In Cyclic Steam and Flue Gas pilots, up to 70% of CO2 remained underground following an injection and production cycle.

ClimatecheckTM

As per Sustainable Development Technology Canada (SDTC) methodology, GERI’s Direct Contact Steam Generation (DCSG) theoretical GHGs were evaluated by a third-party evaluator against emissions from conventional Once-Through Steam Generation (OTSG), the closest technology equivalent.

Brightspot climate

Furthermore, GERI’s measurement program has been validated by an independent energy consultancy, Brightspot Climate, to ensure our GHG emissions and benefits are recognized under Canadian federal and provincial regulations.

Water Usage

Steaming

The DCSG “free water” component:
In GERI’s DCSG, natural gas and air are burned to create high-pressure steam, with all the products of combustion injected downhole. Since water is a natural product of the combustion reaction, our DCSG requires approximately 11% less fresh-water input compared to conventional steaming technologies (for the same steam output).

Reducing water usage through improved steam-oil ratio (SOR):
With DCSG technology, the added benefits of co-injecting steam with flue gas (e.g. pressurization from non-condensable flue gases) results in a lower SOR. The lower the SOR, the less water is required to produce oil. The average SOR for Alberta thermal in-situ (CSS and SAGD) projects generally ranges from 2 to 5. By contrast, GERI’s DCSG pilot projects have resulted in a SOR as low as 1.6.

DSCG vs. OTSG water balance comparison

Hot produced water

Eliminating fresh water usage:
When producing hot water (and flue gases), our DCSG Co-Injector can use high total dissolved solids (TDS) reservoir water as a feed-stock, which is an ideal thermal solution for reservoirs containing fresh water sensitive clays and/or in areas with fresh water constraints. By using produced water, we remove the need to draw on additional water sources, and can save produced water disposal costs.

DSCG vs. OTSG water balance comparison

Inside our portable Motor Control Centre (MCC)

Electricity

A large portion of GERI’s DCSG co-injector power requirements are for air and fuel compression. Our compressors are electrically driven with electricity usually supplied with our own portable generators, a design consideration which allows us to connect to grid power if available. If zero-carbon electricity (e.g. solar, wind, or nuclear) is used, GERI’s DCSG technology can recover oil at a carbon intensity of up to 90% less than conventional thermal.*

*Largely depending on how much CO2 remains stored underground

03

Frequently Asked Questions

Operational

Yes. GERI’s patented CasingCooler™ protects wells from elevated temperatures allowing the operator to steam thermally and non-thermally cased and cemented wells.
GERI’s DCSG is capable of injecting up to 10 GJ/hr, 90 m3/d CWE (at approximately 80% quality), and approximately 49 e3m3/d N2, 6 e3m3/d CO2, at 7,000 kPa and 248°C. GERI’s DCSG has operated at rates as low as 1.3 GJ/hr at 1,900 kPa.
To operate at full capacity, GERI’s DCSG requires approximately 15 e³m³/d of natural gas and 85 m³/d of boiler quality feedwater.
GERI’s DCSG has successfully heated produced water on two occasions using 14,000 ppm total dissolved solids (TDS), 1,280 mg/L CaCO₃ equivalent) and 30,000-40,000 ppm water without any significant scaling issues. To generate steam, boiler quality feedwater is required. GERI’s DCSG can utilize nearly any water specified for a Once-Through Steam Generation (OTSG) or drum boiler, as the DCSG is more tolerant to water quality and can be de-scaled relatively quickly, if it occurs.
Yes, when producing hot water. GERI has used a separator at the end of the process, that removes flue gas then re-inserts it into the injection stream in any desired quantity. When generating steam, this is not possible.
Corrosion is a common concern raised in enhanced oil recovery (EOR) projects using DCSG or injecting flue gas. GERI has reduced corrosion to safe, manageable levels, monitored with a corrosion coupon program.  The primary concern with corrosion is oxygen, which can come from slippage or air-rich combustion (often over 2% in typical flue gases). Through iterative design and operational improvements, GERI has reduced O₂ in the injection stream to less than 100 ppm in the vapor phase. Corrosion due to CO2, present in many active steam assisted gravity drainage (SAGD) reservoirs is another concern with flue gas injection. GERI’s flue gas contains about 12% CO₂ on a dry basis, but, factoring in the steam and water, the CO₂ concentration is only about 3.5%. This results in lower CO₂ partial pressures, which are strongly correlated with corrosion rate. Insight from literature also indicates that as temperature increases from ambient to GERI’s operating conditions, CO₂-induced corrosion decreases by an order-of-magnitude, due to the formation of protective corrosion products that slow further corrosion.
Yes. GERI’s DCSG is fully modular, transported with approximately 14 truckloads, takes a week to set-up, and is capable of fitting within a standard 110m x 110m well lease, depending on the layout.
GERI’s DCSG Co-Injector is supported by GERI-owned process modules (air and fuel compressors, electrical generators, tanks). These modules are supplied by GERI, but, alternatively, air and fuel compression and electrical requirements can be provided by the customer.
It takes approximately one week to set up (depending on site-specific factors) and two to three days to rig out.
As of Q4 2025, GERI has conducted five cyclic steam and flue gas stimulations and one hot water demonstration pilot on legacy heavy-oil wells. For more information on these projects please contact us.

Environmental

No, we use these terms interchangeably.

Per Sustainable Development Technology Canada (SDTC) methodology, GERI’s general DCSG greenhouse gas emissions are compared to a conventional Once-Through Steam Generation (OTSG) which is the closest technology equivalent for the thermal recovery of in-situ oil. For specific projects, the same methodology would be used, but may compare GERI to other alternatives.
There are multiple ways to handle the N2 and CO2 that return to surface, and the preferred solution depends on the existing infrastructure and jurisdiction. Some of the options (which may be done in isolation or combination or in parallel) are as follows: send to sales, dilution, reinjection into the same reservoir, disposal (into a different reservoir), venting, flaring, incineration, thermal oxidization, and nitrogen rejection. GERI can provide guidance and recommendations on ideal production strategy, factoring in cost and environment.
On two previous cyclic pilot projects, 50% and 70% of the injected CO2 remained downhole. However, every project is different. Reservoirs have a limited storage capacity which limits how much CO2 can be stored.
Yes. GERI has successfully conducted a multi-week project generating hot water (at 95°C) using high total dissolved solids (TDS) produced water.
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