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Global Geophysical files Glennallen seismic plan Wants to conduct survey for Ahtna as part of search for natural gas as an affordable energy source for Copper River region Alan Bailey Petroleum News
Global Geophysical Services has applied to the Alaska Department of Natural Resources for a permit to conduct a 2-D seismic survey around the Glenn Highway, to the west of the town of Glennallen in the Copper River basin. Ahtna Inc., the Native regional corporation for the Copper River region, has commissioned the survey. In December 2013 the state issued an exploration license to Ahtna for state land around the Tolsona Lake - most of the planned seismic surveying will take place within the approximately 46,000 acres of land encompassed by the license.
Ahtna has said that it is searching for natural gas resources, as a potential energy source for the Copper River region. The idea is to reduce utility costs for local energy consumers, given the manner in which high energy costs are driving some people to leave the region. The export of gas from the region is also a possibility, if a large enough gas resource were to be found, Ahtna has said.
40 linear miles The planned survey lines will total 40 linear miles, forming a grid straddling the exploration license land. Data acquisition will likely take place in early- to mid-December, Global’s permit application says. The clearing of lines for the survey will begin in early November, and the demobilization of the survey equipment will be complete by the end of the year.
The application says that Global anticipates setting up an operations base in Glennallen, using existing roads and trails to access survey lines. Global is negotiating with a landowner over access to some private land, both for conducting the survey and for establishing a staging area, the application says.
The survey will use vibroseis technology, a system that involves the operation of vehicles with equipment that imparts controlled vibrations into the ground. The seismic source signals from the system will be generated at 165-foot intervals along seismic lines, with receivers placed along the lines at 55-foot intervals, to detect the subsurface echoes of the source signals.
The Department of Natural Resources requires comments on the plan by Nov. 7.
Prospective for gas Ahtna’s exploration license lies within the Copper River basin, a broad area of sedimentary rock that lies under the Copper River region and is thought to be prospective for the discovery of natural gas. The geology of the region bears strong similarities to that of the Cook Inlet basin, the prolific oil and gas basin to the southwest of the city of Anchorage.
But the Copper River basin is substantially under explored, having seen the drilling of only 11 wells in the past half century. All of these wells had gas shows. Most recently, between 2005 and 2007, Texas-based Rutter and Wilbanks drilled a well near the town of Glennallen, not far from the Ahtna exploration license area. The Rutter and Wilbanks well found a gas reservoir but, having encountered severe problems associated with excessive downhole pressures and water incursion, the company eventually plugged and abandoned the well.
In January Joe Bovee, Ahtna land and resource manager, told the Alaska Support Industry Alliance Meet Alaska conference that Ahtna is particularly focusing its exploration efforts on the Nelchina sands, a highly pressurized, porous and permeable gas-bearing sandstone that occurs in faulted blocks over an area of roughly 120 square miles. Existing seismic data point to possible gas targets at depths ranging from 4,000 feet to 12,000 feet in the exploration area, Bovee said.
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