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- Geophysical consultants will return this summer to search for oil deposits in Juab County
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LOOKING FOR OIL THIS SUMMER • Doyle Thurman, center, shows the area that oil exploration will be done this summer in Juab County with County Commissioners Val Jones and Chad Winn.
By Myrna Trauntvein
Times-News Correspondent
They are coming back this summer to search for oil deposits.
St. Croix Seismic LLC, geophysical consultants, attended the Juab County Commission meeting seeking surface permitting to gain access onto an area 95-miles square in the area near Levan.
Work will continue in Juab County this summer as geologists continue to search for oil and natural gas in the area near Levan.
Clark Gentry, Russ Nielsen and Doyle Thurman, representing St. Croix Seismic LLC, met with county commissioners seeking a general use permit to allow the work to go forward.
Mills is one of the corners of the mapped area. From there the area will then proceed north to Chicken Creek continue to north of Yuba Reservoir and will be bordered on the east by SR 28.
“It takes a long time to get ready,” said Clark.
The permitting process, getting permission to do the studies on private and public land, took time. However, he said, everything should be in place for crews to do the actual ground work by the end of August 2008.
In the underground mapping, a small, rubber-tired vibroseis truck (Thumper) generates vibrations to create small waves that will travel into the earth, be reflected by layered sediment, and then be recorded by a 720-m-long string of seismometers spread out along the survey line.
The truck shakes the ground slightly, then moves on and leaves nothing behind—only those standing close to the truck can feel the slight shaking in the bottom of their feet.
“This year, 15 percent of the testing will be done by vibroseis truck,” said Clark.
The Thumper drives slowly along the survey line and stops every 5 m to vibrate. A 1.2-m-wide pad is pressed against the ground beneath the truck to carry part of the truck’s 12,000-lb weight, and then the pad is vibrated for about 10-12 seconds. This 10-second “sweep” is repeated several times, and then the truck moves forward 5 m to repeat the process at the next vibration point.
The end result is a several mile long sonogram-like image of the earth from which assessments can be made.
The seismic method is used at the Earth’s surface to image rock structures and estimate rock types that might form underground oil and gas reservoirs.
The method is based on measuring the time that it takes for sound waves to travel from a seismic source (for example a man-made explosion) through the earth to a rock layer that reflects the sound back to a recording device.
“Some dynamite will be used,” said Clark. “It is planned to drill 950 shot holes.”
None of this will have an effect on homes or structures in the area.
With this setup, the geophysicists can interpret seismic reflections from beds 1000 feet below the surface.
“Most 2-D work is done in anticipation of the 3-D work,” said Thurman. “It went very well last year.”
This year, following tests, it will be up to geologists to turn hundreds of millions of points of this vibrational or seismic data into a 3-D map for determining whether or not oil deposits lie below.
First, a computer processes the raw data. Then, looking at vertical sections, the map maker picks out a few points where he or she sees something interesting--where it looks like the sound waves have echoed off a particular kind of geological structure, such as a salt deposit.
Algorithms can define statistical relationships between the data points selected by the map makers, and use these relationships to connect the dots and create a map. The algorithms also calculate the uncertainty of each data point.
Testing will not, in all likelihood be completed by October of this year. Snow made it so that the work was not completed in 2007 until the early part of December and, hopefully, that will not happen this year.
The crews plan to be on-hand for work in June and will need to be out by winter.
“We plan to spend six to eight weeks in the field,” said Thurman.
Commissioners authorized Val Jones, chairman, to sign the condition use permit.
“It is not a conditional use permit,” said Glenn Greenhalgh, county land use planning director. “Only the planning commission can permit a conditional use.”
However, the condition use permit will allow the work to progress in Juab County.
“We are basically trying to get ready to go,” said Thurman. We have three women working in the courthouse getting helping us get permits.”
Seismic data does not directly identify the age of or type of rock. For this, it is necessary to match the seismic reflections with data from drilled wells and knowledge of rocks that can be seen at the surface. The process of labeling seismic reflections with specific rocks is “Interpretation.” It is usually done on a computer screen or with a 3D visualization system.
Wolverine’s discovery well, the 17-1 Kings Meadow Ranch, hit nearly 500 feet of Navajo Sandstone pay in Utah’s Sevier County in late 2003.This well was completed and began producing in May 2004. A second well was completed in September 2004. These two wells are currently producing 1,600 BOPD and 160 BWPD.
Crews are searching for an Juab County version of the Sevier wells.
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