The average recovery rate from oil production has increased from 30% to 70% over the last 50 years. This is due in no small part to the ever-increasing progress in Enhanced Oil Recovery (EOR). Whether through the application of heat, the injection of gas, or the use of chemicals, EOR is becoming more and more important to oil production efficiency.
Steam Assisted Gravity Drainage (SAGD) has been a mainstay of Canadian oil sands and U.S. shale production for many years. Continuous improvement in SAGD and other technologies are providing exciting opportunities for the energy engineering sector.
Ever-increasing Recovery Rates
Traditionally, primary oil recovery was through the natural pressure of the oil and gas within the well and through pumps at the surface to continue the flow of oil after the natural pressure subsided. This yields approximately 20-25% of the oil in a standard well. Secondary recovery, in which liquid or gas is pumped into the well to force remaining oil to the surface, increases this to 40-50%. Water has been used extensively (especially on offshore rigs), while various gases have also been used successfully.
In more recent times, tertiary recovery has been the dominant driver of production increases across Canadian and U.S. shale and oil sand reserves. Total recovery rates of up to 75% or more are now possible with modern SAGD processes.
Oil producers are now looking to further increase the yields from current projects. North American shale and Canadian oil sands producers are under pressure from lower cost production in the Middle East and elsewhere, but as the recent energy crisis hit and supply tightened, new ways of maximizing recovery rates have once again come to the fore.
Moving Beyond Traditional SAGD
In traditional SAGD processes, water is heated using natural gas (or other heat sources) to create steam which is pumped into the well. The steam heats the surrounding bitumen, reducing its viscosity, with the oil dropping to a lower well for production. Energy costs to create the steam and emissions from production are a key concern for many producers.
Over the last five years, significant developments in modified versions and alternatives to SAGD have been made. More recently, the use of solvents to complement SAGD has become more commonplace. The reduction or elimination of steam from the process has been achieved in some cases, with solvents doing the majority of the work.
Increasingly efficient chemical formulations are being developed and deployed to reduce energy costs, reduce water usage, and increase recovery rates.
CO2 and Carbon Capture
The use of gas for secondary or tertiary recovery has been around for many years. A key development targeted by many researchers is the ability to use carbon dioxide which has been captured from the environment for use in zero net emission oil production.
In December 2022, we saw a shift in policy in the U.S., with oil producers receiving funding for development of carbon recovery systems. The US Department of Energy announced that part of the $3.7 billion USD carbon reduction package would be available to oil producers. This will be welcome news to many in the industry, as cost overruns on new technologies and inflation are putting pressures on budgets for oil recovery projects.
“I do believe that this will become the preferred option to ensure that we can continue the production of low carbon fuel for those that need it” said Occidental’s Chief Executive, Vicki Hollub. Occidental’s Direct Air Capture (DAR) facility in Ector County, Texas is expected to be the world’s largest commercial carbon capture facility, at a cost of $1.1 billion USD.
SAGD and Solvents
SAGD has been used extensively in heavy and in situ oil production in North America since the 2000s. It has been successful in expanding the oil sands of Canada and the shale sands of the U.S. SAGD was a revolutionary process back then, but new approaches are emerging which look to reduce the energy input required.
Many major projects have proven the effectiveness of Vapex (Vapor Extraction); using vapors or solvents instead of steam, such as propane, butane and other proprietary solvents.
The mixture reacts more efficiently with the bitumen to alter the surface tension between solids and liquids and allow for a greater flow of oil. Additional drilling wells are required to recover the solvent for processing and reuse.
Enhanced Modified Vapor Extraction (EM-VAPEX)
Modern variants of the Vapex process include EM-Vapex (Enhanced Modified Vapor Extraction). This process includes the injection of a solvent vapor into the well at the start of the well’s lifecycle. The solvent vapor improves bitumen recovery and greatly reduces the amount of steam and water required, versus traditional SAGD.
According to Emissions Reduction Alberta (ERA), a government funded agency working to advance green technologies, it is estimated that up to 76% more recovery can be achieved versus traditional SAGD.
“There are a lot of technologies out there in various stages of development and the challenge is getting them ready for deployment in the field as quickly as possible,” said ERA Chief Executive Justin Riemer.
Chemical Injection & Polymer Flooding
Traditional oil and gas well flooding used water, especially at offshore oil wells where seawater is in plentiful supply. The use of more specialized chemicals and polymers has greatly improved the performance of the technique and reduced the amount of energy and wastewater produced.
Polymer flooding consists of the introduction of long chain polymers, combined with water, to reduce the viscosity of the oil. This increases the sweep efficiency, a measure of the effectiveness of an EOR process that depends on the volume of the reservoir contacted by the injection fluid.
Surfactants are materials which decrease surface tension between oil and water and improve the overall effectiveness of the process. Different versions of this process exist with caustic and alkaline chemicals used to emulsify the water and oil and improve production rates.
Microbial EOR could be a viable technology in the near future. Microbial bacteria are flushed into a reservoir in which they consume some of the oil producing solvents. These solvents mix with the oil to reduce its viscosity, making it potentially suitable with heavy oil reservoirs. Some bacteria may combine effects, in that they produce solvents and natural surfactants, which work in the same way as the polymer method described above.
Potential Microwave Technologies
As technologies advance, ever more processes are being developed. In rethinking the processes, the challenge becomes how to most efficiently transfer energy to the bitumen.
SAGD applies heat to the bitumen through the injection of steam; Vapex is more direct in its use of solvents (and less or no steam). But can the energy be applied directly to the bitumen itself?
Development of the use of microwave radiation which can be applied directly to the sand and bitumen is underway with promising results. Researchers have successfully applied microwave energy directly to the geological formations. In principle, trapped water molecules could be turned into steam in the ground which transfers heat to the rock and oil. Suncor have attempted the technology most prominently in their Dover oils sands site.
It is thought that there are significant challenges to commercializing an entirely microwave production facility, but significant reductions in water and energy inputs are worth pursuing.
In many recovery methods, high energy costs are required, especially in the creation of steam. Higher energy costs are putting pressure on the margins of producers. Carbon neutrality targets are harder to meet when the production depends on high levels of energy being inputted to the extraction process.
When carbon dioxide is used during gas injection, scaling issues must be faced around the issue of carbon transport and storage. Ideally, in the North American Permian region, carbon could be captured and transported from nearby power plants. Further afield, the current methods of storage and transportation must advance before viable commercialization of the process can occur at scale.
As the search for viable alternatives progresses, proving any new technology at the scale of commercial readiness can be difficult. Process development funding and technology development projects may come to the fore in the months and years to come.
The opportunity to use carbon capture to achieve zero-carbon production during oil extraction is one of the holy grails of energy production in 2023.
As Emissions Reduction Alberta chief Riemer was quoted, “We’ll see the adoption of new technologies to be sure, but we’ll also need to see large scale adoption of existing and proven technologies in the future…There’s huge potential and huge opportunities in Alberta”.
Increased Efficiency and Profits
New phases of drilling and expansion are required more quickly and frequently for oil sands compared to onshore or offshore facilities.
New wells are needed, and renewed investment required, when the oil dwindles after each phase of production. Extending the life of each individual phase represents a major cost avoidance. Increasing the efficiency of each well saves on infrastructure and expands the ROI of the initial investments.
Reduced Water, Energy, and Environmental Impacts
Reducing the amount of steam required (or eliminating it entirely) reduces the amount of water diverted into oil production. Optimizing the effectiveness of chemicals and solvents means that quantities of material released into the ground are minimized.
Many new methods have the advantage of avoiding the creation of tailing ponds which cause difficulty in terms of environmental impact and clean-up costs.
As future technologies develop, exciting opportunities present themselves for upstream producers and engineering companies.
Need help with an EOR project?
Vista projects is an integrated engineering services firm able to assist with your Enhanced Oil Recovery project. With offices in Calgary, Alberta, and Houston, Texas, we help clients with customized system integration and engineering consulting across all core disciplines. Contact us today to start the discussion!