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Gary Dolberry on Enhanced Oil Recovery

Updated on August 27, 2008

In the United States, both citizens and leaders alike are coming to understand the importance of the nation as a whole becoming more energy independent. This is why the U.S. is currently engaged in a critical search to develop more of its own sources of fuel. One strategy that is quickly growing in prominence and application with respect to petroleum is Enhanced Oil Recovery (EOR), also known as tertiary recovery.

Simply put, EOR describes a set of techniques utilized to increase the amount of oil that can be extracted from any oil field. Many oil exploration and drilling companies are using EOR techniques to maximize the potential of oil fields both old and new. As our nation’s quest for energy independence intensifies, the application of EOR techniques will grow into an even more commonplace practice for getting as much oil out of the ground as possible.

Gary Dolberry is the founder and President of Dolberry Oil and Gas, based in Dallas, TX. Dolberry Oil is a forward-thinking oil exploration and drilling company that was an early-adopter of Enhanced Oil Recovery techniques. In fact, Gary Dolberry built his company on the idea that multitudes of oil fields had already been drilled that still possessed vast potential for future extractions. With over 30 years in the industry, Mr. Dolberry obviously was able to develop acute intuition regarding the oil fields of the Southwest as well as which techniques could best maximize their potential.

Mr. Dolberry was gracious enough to share with me some insight on Enhanced Oil Recovery and its potential to enhance the energy landscape that is an integral part of the foundation of our nation’s economy and Americans’ everyday lives.

Phases of Oil Production

Let’s begin with a short summary of how oil production works. There are basically three phases: primary, secondary, and tertiary recovery. During the initial primary phase of oil production, oil is driven into the well bore by the natural pressure of the reservoir and gravity. The natural movement of the oil is enhanced with artificial lift techniques such as pumps. Primary recovery can typically lead to the extraction of 10-20% of a field’s available oil.

Secondary recovery efforts will typically utilize water, in a technique known as water flooding, or gas to displace oil and compel it to a well bore. An additional 10%-30% of a field’s potential can be recovered in the secondary phase. Tertiary oil recovery, or enhanced oil recovery, utilizes several additional methods that are expensive and can sometimes be unpredictable, but that can ultimately allow for 30%-60% of a field’s total oil potential to be realized.

Brief History of EOR

The United States, and Texas especially, is littered with oil fields that have been drilled, had oil extracted, and then been abandoned without the field’s full potential being realized. By the 1990s, as the oil industry ground to a virtual halt, experienced oilmen like Gary Dolberry saw the significant level of potential in shifting their focus away from exploring new fields and towards extracting more oil from fields that had already been drilled. One example of the power of EOR techniques is the Salt Creek oil field in Wyoming.

Anadarko CO2 pipeline to Salt Creek
Anadarko CO2 pipeline to Salt Creek

In 1978, the Salt Creek field was producing 6.3 million barrels of oil per year. The number had dropped to 1.7 million by 2004. Not only had Wyoming’s statewide oil production been dragged down in the process, significantly affecting the state’s economy, but the Salt Creek field was expected to be dry by 2020. Enter Anadarko Petroleum Corporation, who utilized an EOR technique known as gas injection to revive the Salt Creek field and almost single-handedly reverse the entire state’s decline in production.

Not only has Anadarko help to improve Wyoming’s economy, it has found a handsomely rewarding investment for itself. Anadarko originally viewed the project as profitable when oil prices ranged in the $20 amount per barrel. In July of 2005 oil prices had risen to between $50 and $60 per barrel. In the short time since then, prices have more than doubled. This increase in return on investment is a major part of the reason why oil companies like Anadarko and Dolberry Oil are able to afford the upfront capital expenditures necessary to utilize EOR.

EOR Technique: Gas Injection

The most popular and growing EOR technique, accounting for 50% of EOR production in the United States, involves gas injection. Gas injection has proven to be the most consistently successful technique for increasing oil production in various types of oil reservoirs. Many major oil companies have taken advantage of the gas injection technique since it was first attempted in Surry County, Texas in the 1970s.

The ultimate goal of gas injection is to restore reservoir pressure, increase oil production, and lower operating costs. One reason that this method of EOR has not seen more widespread application is the high upfront investment costs for the requisite equipment and gas components. While gas injection can result in lower operating costs, this high initial fixed cost was the barrier to entry into gas injection EOR for many smaller independent oil companies. As previously mentioned, the investment return made possible by rising oil prices has led the way for even smaller independent oil companies to get into the game as well.

Gas injection involves carbon dioxide, nitrogen, or natural gas being injected into a reservoir. Once injected, the gas expands and compels additional oil into a production wellbore where it can be extracted. The gas will subsequently dissolve into the oil and both lower the viscosity of the oil and improve the oil’s flow rate. In many applications of gas injection, up to two-thirds of the injected carbon dioxide will return with the oil that is produced. Re-injecting the recycled carbon dioxide to release additional oil will then minimize operating costs.

Illustration of Gas Injection EOR
Illustration of Gas Injection EOR

Communities such as Midwest, Wyoming, are also experiencing ancillary benefits from gas injection EOR performed by companies like Anadarko Petroleum. The utilization of gas injection EOR cleared the landscape of many unsightly power poles, conventional pumping wells, and power lines. Plus, tons of greenhouse gases were prevented from polluting the atmosphere. As Anadarko spokesman Rick Robitaille told the Casper Star-Tribune, “It’s good for the economy. It’s good for the country. It’s good for the environment. It’s a very positive scenario.”

EOR Technique: Thermal Recovery

Thermal recovery accounts for the other half of EOR production in the United States. The thermal recovery technique is primarily utilized in the oil fields of California. Essentially, thermal recovery uses heat to improve oil flow rates. Steam will be injected into the reservoir to lower the viscosity of heavy viscous oil, allowing the oil to more easily flow through and be extracted. Dolberry Oil estimates that steam accounts for 52% of the market methods utilized for EOR. In comparison with gas injection, carbon dioxide is at 31% and nitrogen is at 17%.

Gary Dolberry and Dolberry Oil and Gas actually have access to a proprietary steam injection thermal recovery technology that most oil production management companies do not. The technology is commonly referred to as “steam slugging” and involves a mixture of carbon dioxide and steam that results in roughly twice the recovery efficiency of hydrocarbons in two-thirds the elapsed time. Steam slugging has typically produced results in the range of ten additional barrels per day, and also provides added benefits like well bore cleaning and water disposal.

Illustration of Thermal Recovery EOR
Illustration of Thermal Recovery EOR

A strategy that is commonly utilized by companies who have access to steam slugging is what is called a “Huff and Puff” scenario. In this scenario, each well is subjected to 8-12 hours of injection – the “Huff.” The well then undergoes a 12-15 hour “Soak” period in which carbon dioxide mixes with the crude oil while nitrogen pull the oil to the lowest pressure area. Steam then provides additional pressure that produces greater oil production as the additional heat assists in loosening the crude oil in the “pay zone” surrounding the well. Finally, during “Puff” cycle, the well bore and surrounding pay zone fill with fluid that will be produced or recovered.

EOR Technique: Chemical Recovery

Another technique that is utilized in less than one percent of all EOR efforts is chemical injection, in which long-chained molecules called polymers are used to increase the effectiveness of water floods. Water flooding is a widely utilized secondary EOR technique used to increase overall field output while achieving higher oil to water ratios.

The Future of Enhanced Oil Recovery

While many Americans and the economy have been hit hard by rising fuel costs, one ancillary benefit of the increase in oil prices has been the additional incentive for oil companies to invest in the development of EOR technology. Dolberry Oil and Gas is one of many smaller independent oil exploration and oil production management companies that are focusing on effective application of the latest innovations in Enhanced Oil Recovery techniques. These companies are joined by none other than the U.S. Department of Energy (DOE), which recently announced the development of an EOR program to “enable enhanced recovery of the nation’s stranded oil resources”.

One concern whenever oil drilling and carbon dioxide become the topic is the potential impact expected on the environment. There is reason to believe that the impact could be quite positive, according to a recent analysis conducted by the International Resources Group (IRG) studying the effect of climate legislation on the supply of carbon dioxide for EOR. Due to the growing profitability of carbon injection EOR, climate legislation such as the Lieberman-Warner Climate Security Act will, in effect, spur companies to develop more advanced technologies for efficient carbon usage; one example being carbon capture systems. Such policies, which essentially incentivize the capture of industrial carbon dioxide, can serve two purposes: 1) assist the U.S. in recovering untapped oil reserves; and 2) reduce global warming pollution.

U.S. Basins/Regions Studied for Future Potential for CO2-EOR.
U.S. Basins/Regions Studied for Future Potential for CO2-EOR.

There is little doubt that Enhanced Oil Recovery techniques will pay tremendous dividends for the U.S. in the long-term. The DOE estimates that an additional 240 billion barrels of recoverable oil resources could potentially be generated with full usage of “next generation” carbon dioxide injection EOR. Estimates place the amount of oil still in the ground in the U.S. alone at more than 1 trillion barrels. There really is no telling how much more of that oil will become recoverable as Enhanced Oil Recovery technology continues to evolve.

Primary Article Source

Gary Dolberry started in the oil business over 30 years ago, and is currently the President of Dolberry OIl and Gas. Mr. Dolberry is a graduate of Midwestern State University. Prior to founding Dolberry Oil and Gas, Gary Dolberry worked for Halliburton and Camino Petroleum Corporation of North Texas. He then joined Burke Oil Company of Dallas as Vice President of Field Operations for Texas, Louisiana and Oklahoma. Mr. Dolberry also established himself as an independent contractor and worked extensively for the State of Texas.


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    • profile image


      4 years ago

      Why wouldn't sand being pumped in from the ocean not work. Being heavier it should re-create the pressure needed to force the oil to be pumped out. Even better it would refill the whole and stop the fracture process. We have a whole ocean full of sand and if we do not do it with coastal areas it should be better then making sink holes, sinking land and earth quakes.

    • Hunter Goodman profile image

      Hunter Goodman 

      7 years ago from Texas

      Secondary and tertiary recovery are the future to production in America with the bulk of the stripper well production. Nice work!

    • profile image

      co2 injection 

      9 years ago

      <!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0in; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:8.5in 11.0in; margin:1.0in 1.25in 1.0in 1.25in; mso-header-margin:.5in; mso-footer-margin:.5in; mso-paper-source:0;} div.Section1 {page:Section1;} -->

      This is a great read. There is still plenty of oil under our soil. EOR will be a great help to jumpstart our independence from foreign oil.


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