GREEN RIVER - At present, there is no commercial production of oil shale being undertaken in the United States. That may be about to change, however.

The Bureau of Land Management recently finalized a plan to guide the use of public lands containing oil shale and tar sands, with an end goal of allowing some form of commercial development.

The agency's final programmatic environmental impact statement, released in September, aims to amend 12 land-use plans in Wyoming, Colorado and Utah.

Under the amendments, the agency would set aside about 1.9 million acres of public lands for potential commercial oil shale development.

In Wyoming, the amended plans would include the Great Divide resource management plan, the Green River resource management plan, and the Kemmerer resource management plan.

The agency's program promotes economically viable and environmentally sound production of oil shale on Western lands, BLM officials say.

The agency estimates oil shale deposits in the three Rocky Mountain states hold the equivalent of 800 billion barrels of oil - enough to meet U.S. demand for imported oil at current levels for 110 years.

Congress directed the BLM to develop the study as part of the Energy Policy Act of 2005.

The programmatic study is one in a number of steps required before commercial leasing would begin. BLM officials said the next step will be to complete rules that govern the procedures for issuing leases for oil shale development.

Huge resource

Most oil shale resources are found in the Green River formation located in the Piceance, Uinta, Green River and Washakie basins in Wyoming, Utah and Colorado.

The BLM's study identified the most geologically promising areas for oil shale development. The areas were rated on the basis of the grade and thickness of the deposits.

There are about 2.2 million acres within the Green River and Washakie basins that were identified as the most promising areas in Wyoming. The area includes about 1.2 million on BLM-administered federal lands.

Most of the geologically promising oil shale resources in Colorado and Utah are contained in deposits that yield 25 gallons of shale oil per ton of rock or more. Those deposits are 25 feet thick or greater.

In Wyoming, where the oil shale resource is not of as high a quality as it is in Colorado and Utah, the most promising oil shale resources are those deposits that yield 15 gallons of shale oil per ton of rock or more, and are 15 feet thick or greater.

Research projects

In the summer of 2005, the BLM initiated an oil shale research, development and demonstration program under which small tracts of land could be leased in support of activities to demonstrate the technical and economic feasibility of oil shale extractive technologies.

The BLM solicited the nomination of parcels, not to exceed 160 acres, to be used for oil shale research and development activities. The leases were to be issued for 10-year terms, with an option to extend them another five years.

The BLM received a total of 20 nomination packages from a variety of companies. After review, the agency selected six projects. Five research and development leases were issued in Colorado, and one was issued in Utah.

Colorado's five projects are grouped together in the Piceance Basin in an area southeast of Rangely. Companies involved in the projects include Chevron Shale Oil Company, EGL, which is now known as the American Oil Shale LLC, and Shell Frontier Oil and Gas Inc., which has three of the projects.

Utah's project site lies in the Uinta Basin and is being pursued by the Oil Shale Exploration Co.

There are currently direct and indirect oil shale recovery methods. Direct recovery methods include surface and underground mining where the oil shale is removed and processed.

Indirect methods recover the oil from the underground deposits without requiring the excavation of the oil shale.

To separate the oil from the shale, companies use retorting technologies that apply heat to the rock to chemically change the shale to liquids that can then be collected.

What is oil shale?

The term oil shale generally refers to any sedimentary rock that contains solid bituminous materials, called kerogen, that are released as petroleum-like liquids when the rock is heated in chemical processes. Oil shale can be mined and processed to generate oil similar to oil pumped from conventional oil wells. However, extracting oil from oil shale is more complex than conventional oil recovery and is more expensive.

How did oil shale form?

Oil shale was formed millions of years ago by the deposition of silt and organic debris on lake beds and sea bottoms. Over long periods of time, heat and pressure transformed the material into oil shale in a process similar to how oil is formed.

Where are the resources?

Oil shale is found in many places worldwide, but the largest deposits in the world are concentrated in the Green River formation, which covers portions of Colorado, Utah and southwest Wyoming. More than 70 percent of the total oil shale acreage in the formation is located on federally owned and managed lands.