CORVALLIS - Researchers at Oregon State University have discovered promising geological formations and areas in the Coast Range near Roseburg, Ore., that have the potential for commercial deposits of natural gas.
The findings conclude a five-year, $110,000 research effort. They build on geologic mapping by the Oregon Department of Geology and Mineral Industries (DOGAMI), a leading sponsor and research collaborator, and the U.S. Geological Survey, and are outlined in a 141-page report released today by DOGAMI.
The most promising formations detailed in this research, scientists say, might yield gas fields that approximate those developed at Mist in northwest Oregon, which have produced $100 million in natural gas since 1979.
"This area is not going to be the next Gulf Coast for gas or oil," said Alan Niem, an OSU professor of geology. "But the team has found geologic features no one ever knew existed. We've really narrowed down the best sites for exploration and feel strongly that some spots have good potential."
The next step, Niem said, will be for private industry to review the maps and data in the new report and make decisions on whether to drill wells.
"Exploration for oil and gas is beginning an upswing in the U.S. right now, and there's more awareness than there used to be about some of Oregon's geologic potential," Niem said.
"Also, this area has existing gas pipelines, it's close to growing population centers that could use the supply, and the potential fields are relatively close to the surface," he said. "Further exploration is warranted."
The area, geologically referred to as the Southern Tyee Basin, is in the southern Oregon Coast Range, dominated by Douglas- fir forest and streams, and includes about 3,500 square miles in Douglas and Coos County, and small portions of Lane and Curry County.
But 50 million years ago, the picture was quite different.
Then, during the Eocene epoch, the Tyee Basin was the site of massive deltas and subtropical, coal-forming swamps fed by huge rivers. At various times, large parts were submerged beneath the ocean and deep marine sediments and submarine "fans" were deposited.
This basin was filled over millions of years with about four miles of sedimentary rock that lies on top of a volcanic basement. Parts were crushed against and thrust under the Klamath Mountains. Faults, volcanism and tectonic forces helped shape and elevate the land to its present form.
In the process, researchers now know that the unique ingredients that can form oil, gas or coal were present in at least some parts of the basin. These include source rocks full of organic material, porous reservoirs for oil or gas accumulation, sufficient heat and time to "cook" the sediments, impermeable cap rocks and traps to help concentrate the hydrocarbons.
"To create oil and gas, each of these steps has to be present, occur in the correct order and at the right time," Niem said. "That doesn't often happen. You might have one factor needed to form natural gas or oil, such as source rocks, but lack another factor such as heating of those rocks."
But using some of the more sophisticated new tools and techniques available to geologists - sequence stratigraphy, subsurface data and new geologic mapping by DOGAMI and the U.S. Geological Survey - the researchers have created a far more detailed view of this area's geology than ever before. And they've discovered clear evidence of natural gas in about 25 "seeps" along fault lines and in some residents' water wells.
"In a few cases we were able to demonstrate our findings by putting a match to a water well and watch flames burn a few feet long," Niem said.
Among other things, the studies show why previous oil and gas wells drilled in the basin, about 15 of them, were non- productive.
"Basically, they always drilled in the wrong spot in the past," Niem said. "Our new understanding of this area's geology can show why that is so. Now, we know which are the better areas to explore and what to expect - a natural gas province."
Overall, Niem said, the study showed most areas of the Tyee Basin had low to moderate potential for oil, natural gas or commercially-useful coal deposits. But there were exceptions, especially for the natural "methane" gas similar to that being produced in the Mist field.
"We found four major structural traps that should merit exploration for natural gas," Niem said. They include:
-The Williams River-Burnt Ridge anticline, which is west of Melrose and north of Camas Valley;
-The Western Cascades foothill and Bonanza thrust, between Nonpareil and Glide and to the east;
-The Myrtle Point-Sutherlin sub-basin, from Glide to Powers and to the south;
-The Tyee Mountain anticline, a large area northwest of Drain.
Within those areas, Niem said, petroleum geologists from private industry could target specific drilling sites using some of their even more powerful tools, such as "three-dimensional seismic," Niem said.
In continuing research, OSU scientists are doing further study of geologic formations near the Mist gas field and in some promising areas of southwest Washington state.
Such research, Niem said, provides a wealth of fundamental data about Oregon's geology at the same time it improves the chance for future petroleum or natural gas discoveries and the accompanying economic development.
The final study was done by Niem, his wife and co-principal investigator Wendy Niem, and OSU doctoral student In-Chang Ryu, using work by Gerald Black and Tom Wiley of DOGAMI and Ray Wells of the USGS.
Funding support was provided by DOGAMI, the U.S. Forest Service, the Bureau of Land Management, Douglas County, the Oregon Lottery and several private timber and energy companies. They include GCO Minerals Co., Menasha Corp., the Oregon Natural Gas Development Corp., Seneca Timber Co., and Weyerhaeuser Corp.
Copies of the new study are available from DOGAMI at a cost of $20.
To obtain a copy, contact Nature of the Northwest Information Center, Suite 177, State Office Building, 800 N.E. Oregon Street No. 5, Portland, Ore., 97232-2109, telephone (503) 872-2750; or the DOGAMI Grants Pass Field Office, 5375 Monument Dr., Grants Pass, Ore., 97526, telephone (541) 476-2496.
Orders under $50 require prepayment. Ask for report OGI-19.