Heavy Oil

Heavy oil is a vast U.S. oil resource that is underexploited because its highly viscous nature renders it difficult to produce and to refine.

As higher-gravity crudes (lighter oil) become increasingly scarce in the U.S., American operators are looking more and more to low-gravity crudes (heavy oil) to prop up the Nation’s declining oil output. Heavy oil generally is defined as having an API (American Petroleum Institute) gravity of 10-20 degrees. Oil sources with even lower gravities, such as extra-heavy crudes, tar sands/oil sands, and bitumen, are considered unconventional oil resources.

The original-oil-in-place (OOIP) volume of heavy oil in the United States was 105 billion barrels. U.S. heavy oil cumulative production to date totals about 13 billion barrels. This relatively small percentage of recovery is because heavy oil is thick and resistant to movement. It’s both more costly and more time-consuming to get that oil out than it is to produce lighter crude oil grades.

However, advances in oil production technology are making the production of heavy hydrocarbons a commercial reality. DOE has played a pivotal role in the research and development partnerships that have brought these advanced technologies into the marketplace.

NETL research seeks to create better methods for characterizing heavy oil reservoirs, which are needed in order to more efficiently apply thermal enhanced oil recovery methods to such reservoirs. Much of America’s heavy oil is produced via a costly steam injection enhanced oil recovery (EOR) method to produce a crude oil grade that is lower in quality and thus sells for less.

NETL also pursues research to develop more-efficient approaches and novel technologies to unlock this massive underutilized resource. The Nation’s largest untapped conventional heavy oil resource lies within some of America’s most inhospitable terrain for oil operators: Alaska’s North Slope. Combined OOIP volumes for the two less-viscous heavy oil formations on the slope total about 10–20 billion barrels. North Slope operators have had some success producing the less-viscous crudes in the West Sak and Schrader Bluff formations by injecting slugs of water alternating with gas (WAG) into the reservoirs; the gas acts as a solvent to reduce oil viscosity, while the water front helps sweep the reservoir, pushing the crude to producing wells. DOE-funded research by the University of Houston has developed tools for modeling the optimum WAG flood design.

Because of the expense of production and the lower price for heavy oil, most U.S. thermal EOR is limited to the giant heavy oilfields of California, where operators enjoy economies of scale. Significant heavy oil resources elsewhere are “stranded” because they cannot be economically produced. Another NETL project has resulted in the commercialization of a new technology that could produce more of this stranded resource at less cost and with reduced environmental and safety risks. A small Texas firm developed, with DOE funding, a method for producing heavy oil that offers a low-cost alternative for inhibiting production of sand in an oil well—a major barrier for economic recovery of heavy oil. This “Teleperfs” technology—featuring built-in telescoping perforating devices that establish a continuous fluid-producing formation .

Photo ofheavy oil production facilities in giant Wilmington oil field, in Long Beach, CA

Heavy oil is a vast U.S. oil resource that is underexploited because its highly viscous nature renders it difficult to produce and to refine. NETL research seeks to develop better methods for characterizing heavy oil reservoirs, which are needed in order to more efficiently apply thermal enhanced oil recovery methods to such reservoirs. Shown are heavy oil production facilities in giant Wilmington oil field, in Long Beach, CA, featured in the project sheet entitled Increasing Heavy Oil Reserves in the Wilmington Oil Field through Advanced Reservoir Characterization and Thermal Production Technologies, Project No. DE-FC22-95BC14939.

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