Oil shale has potential for supplying fuels for many decades, although numerous attempts during the last 100 years have led to only a few commercial projects.
But with projections for a steady rise in world energy needs, fuel production from oil shale can add to the mix of energy sources that the world will require.
Estimates are that the world has about 2.8 trillion bbl of shale oil in place with about 1.5 trillion bbl in the Green River formation of Colorado, Utah, and Wyoming. Green River recoverable resource estimates range from 0.5 to 1.1 trillion bbl, based on a 15 gal/ton cut off.
Oil shale is a general term for sedimentary rock containing a solid organic matter (kerogen) that yields liquid oil, gas, and water when heated either in situ or in surface retorts.
Estonia, China, and Brazil have commercial oil shale projects that have operated for many years. These projects produce about 14,000 bo/d.
The recent 29th Oil Shale Symposium at the Colorado School of Mines in Golden, Colo., updated some of the ongoing projects and technologies.
Utah
Two projects in Utah could move into a production phase in this decade.
Gary Aho, vice-president of operations, Oil Shale Exploration Co. (OSEC), told the symposium that if all partners approve the project by earlier 2010, OSEC could begin producing shale oil from three retorts in 7 years and reach 50,000 bo/d from 12 retorts by 2027.
Aho said after partner approval, OSEC would need 4 years to receive all permits required and another 3 years for building and installing the first three retorts. Petroleo Brasileiro SA (Petrobras) and Mitsui & Co. Ltd. are OSEC's partners.
The project will use both underground and surface mining for feeding Petrosix retorts. Petrobras developed and has operated since 1992 a Petrosix retort in Sao Mateus do Sul, Brazil.
The OSEC project also includes installing two hydrotreaters so that the company can move premium product to market.
Aho said OSEC's leases cover 46,000 acres and hold 4.5 billion bbl in place with an estimated 2.7 billion bbl recoverable.
Red Leaf Resources Inc. operates a 16,800-acre leasehold in Utah with an estimated 1.5 billion bbl in place and may begin a 8,000 bo/d commercial demonstration project in the next 2 years. James Patten, chairman, president, and chief executive officer of Red Leaf, related to the symposium the success of its EcoShale technology pilot.
The technology involves placing oil shale in an excavated quarry lined with impermeable layers and sealed with a bentonitic clay. Pipes transfer dry, low-emission heat from natural gas burners to the oil shale. Red Leaf notes that no rock burns so that the process avoids typical retort emissions.
The process produces a 39° gravity kerogen oil. After recovering the oil, the process includes removing the pipes and moving to a new site, while reclaiming the initial site.
Colorado
Roger Day, vice-president of operations, American Shale Oil LLC (Amso), noted that in 2010, Amso would begin a pilot of its in situ technology on one of the US Bureau of Land Management research, development, and demonstration leases.
Amso is one of four companies granted leases by BLM for demonstrating proprietary processes of commercial shale oil production. Except for the Utah lease granted to OSEC, all the BLM leases are in Colorado's Piceance basin. Shell Exploration & Production Co. and Chevron Corp. are the other companies holding BLM RD&D leases.
Amso technology involves heaters for recovering shale oil initially from a zone below a freshwater aquifer. The pilot test will involve a single heater-producer well traversing the zone at 60°. During last year, Amso completed numerous exploration and hydrology wells for evaluating the site.
Shell continues tests of its freeze-wall technology for developing oil shale in zones in contact with an aquifer. Shell expects the freeze wall to keep water out of the heated zone and keep hydrocarbons from entering the aquifer. Shell's tests are on private lands and not on its BLM RD&D leases.
ExxonMobil Corp. has started to test its Electrofrac method in horizontal wells drilled and hydraulically fractured from its Colony oil shale mine. The technology fills the hydraulic factures with electrically conductive material for distributing heat to the oil shale.
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