By Heba Hashem in Dubai

Steam Enhanced Oil Recovery (EOR), also known as thermal EOR, is an effective and commonly used method of increasing production from heavy oil resources and tight formations.

Although the basic theory of steam injection to increase the reservoir temperature and pressure hasn’t changed drastically over time, the method and source of generating steam has evolved.

For heavy oil operations in sunny regions, solar generated steam can now supplement, and in some cases completely replace, the steam generated from natural gas.

“Giant heavy oil deposits primarily exist in places like under the lake of Maracaibo in Venezuela, in California, in the Arabian peninsula- especially in Saudi Arabia, in the Sultanate of Oman and to a lesser extent in the United Arab Emirates & Egypt”, explains Amr Mohsen, founder of Lotus Solar Technologies.

“Now, it is getting progressively difficult to justify the burning of precious natural gas, particularly in the presence of a green alternative heat source”, he adds.

Advantages of solar EOR

One of the main advantages of solar EOR is having no fuel costs, with very low operations and maintenance costs- typically $0.35 per MMBTU. This allows solar steam generators to operate long after the lifespan of an equivalent gas-fired unit, which can increase proven reserves and maximize utility recovery from a field.

Moreover, solar EOR systems can easily integrate with existing gas-fired steam generation systems, allowing for a hybrid design that generates steam 24 hours a day all year long, under different weather conditions.

Oilfields in areas lacking natural gas will especially benefit by creating and injecting steam for EOR without the capital investment of a gas infrastructure. This will particularly appeal to regions where natural gas is unavailable or is in limited supply, such as some parts of the Gulf Cooperation Council (GCC).

With zero carbon dioxide and nitrogen oxides emissions, the solar EOR systems eliminate the financial risks of permitting costs, ongoing cycles of burner upgrades, and carbon taxes. This facilitates meeting the tough regulatory criteria for pollutants and carbon dioxide.

On an economic level, solar steam frees the largest and most irregular part of thermal recovery production cost. Depending on local sunshine, solar EOR systems can generate steam at an average cost from $1.75 to $3.00 per MMBTU. Even with the current low gas prices, the ongoing fuel savings would be significant.

Natural gas prices are extremely volatile, and while today’s prices are relatively low at $4.00 per MMBTU, energy consulting firm Wood Mackenzie forecasts a price increase to $6.50 per MMBTU over the next five years. Such extreme price fluctuations make it difficult for heavy oilfields to develop production schemes.

Having a predictable, fixed-price plans would make it easier for operators to reassess optimal recovery strategies to achieve higher production rates by steaming wells harder, and increase a field’s ultimate recovery fraction.

EOR solar collector innovators

In the 1980’s, ARCO pioneered solar steam generation with a pilot solar tower. More recently, Shell sanctioned a project to produce steam for EOR via a parabolic trough system in Oman, while Chevron is building a solar tower steam project in California.

Although these systems have proven technical feasibility, the high capital costs of trough and tower collectors have limited the deployment of solar EOR.

For the first time, California-headquartered Glasspoint have developed solar collector systems that enable field engineers to develop resources with fixed-price steam below market prices.

The solar steam generators produce at predictable, low operation costs for the entire 30-year life of the system- hence increasing proven reserves while greatly enhancing the value of the asset. 

The company’s innovative solar thermal design combines ultralight, low-cost components in a highly durable configuration specifically developed to withstand rugged oilfield environments with minimal operation intervention.

Since the amount of solar-generated steam varies by time of day and year, continuous constant-rate steam delivery can be achieved by using gas-fired steam generators to “fill in the gaps”- when the solar steam rate falls below the desired level.

Glasspoint’s technology is not present in any oil field yet. However, the company received a funding of $3.5 million from Chrysalix Energy Venture Capital,which will accelerate the commercialization of Glasspoint’s solar steam technology and finance the deployment of a solar EOR demonstration plant in California.

Rod MacGregor, CEO of Glasspoint, told Arabian Oil&Gas that the Middle East will soon become the company’s primary market.

“We believe that in the short to medium term, the Middle Eastern opportunity will dwarf the Californian one, obviously there’s a lot more heavy oil in the Gulf that in California”, he said.

Glasspoint is partners with T.J. Cross Engineers, who specialize in heavy industry, with an emphasis on petroleum-related fields and power generation.

According to Stuart M. Heisler, the Engineering Manager and a Principal at T.J. Cross Engineers, operators can deploy solar EOR systems in three ways.

They can displace around 20 percent of their annual fuel costs with a solar-gas hybrid approach, by integrating solar steam alongside existing steam generation facilities and without making changes in the quantity of steam delivered to the field. Automatic control systems for the gas and solar generators communicate to ensure constant rate steaming with no operator intervention.

A second option for operators would be to integrate solar EOR into an existing oilfield with variations in the steaming rate, while a third option is to bypass gas firing and relying entirely on solar steam, especially with the variations occurring in daily steaming patterns.

Solar technology companies step up

Areva Solar’s Compact Linear Fresnel Reflector (CLFR) technology may also be deployed in generating solar steam for oil recovery. 

The company’s CSP technology utilizes CLFR system, in which rows of solar reflectors focus sunlight onto boiler tubes in a linear receiver supported on towers above the reflector field. Each row of CLFR reflectors is driven by independently controlled motors to track the sun, or to rotate for convenient cleaning. 

"We can either boost a coal-fired plant's electricity production by five percent, or reduce the amount of coal they are using," says Robert Fishman, the CEO of Areva Solar.

“For stand-alone power plants, the last few percentage points of production are a big deal. For combined-cycle gas-fired power stations, the CLFR can yield up to 250 Btu per kilowatt-hour heat rate improvement at peak boost”, Fishman explains.

One notable advantage of the CLFR technology over other solar thermal systems is a smaller footprint. For a 200MW plant, tower technology would require twice as much ground area as CLFR, and thin-film technology would require three times the footprint. This could highly benefit installations at existing industrial facilities where open land is limited.

The company believes that the steam from its CLFR could be used in petrochemical, oil recovery, food, water desalination and mining sector applications. According to William Conlon, the senior vice president of engineering at Areva Solar, the Areva system is 20% to 30% less expensive than a parabolic solar thermal process.

On the other hand, Egypt’s Lotus Solar Technologies has completed two major studies for using the strong sunshine in the MENA region to generate that much needed injection steam.

In both heavy oil fields (giant in the Arabian peninsula & small field in Egypt), Lotus drew and presented to oil companies a strong economic case for saving huge amounts of precious natural gas and avoiding its significant harmful emissions to produce the required steam- using the clean and abundant heat resource of the MENA sun.

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