Representatives from Buccaneer Alaska and Weems Geophysical held a second town hall meeting Tuesday to further explain the geophysical survey work planned for in and around Kenai.
Buccaneer is conducting 3D geophysical mapping of its Kenai Loop lease unit.
John Land, the lead permit agent for Weems Geophysical, opened the meeting by explaining that this project was the first in his career in an area that hadn’t previously undergone seismic work. After the first town hall meeting last month, he said he realized that he and his team needed to do more to explain the process to the community.
Joe Crownover, vice president and regional manager for Vibra-Tech Inc., also was on hand to help explain how seismic surveying works. Vibra-Tech, among other things, handles “complex vibration induced issues,” and is the oldest vibration monitoring company in the country, Crownover said. The company has experience in Alaska, including projects in Soldotna and Ninilchik.
Land said the 3D geophysical survey has five phases, beginning with permitting, which is under way.
The next step is a surveying phase, during which all structures and utilities will be marked by GPS. The survey will map the ideal points to set up the seismic sources and receivers, which will then be adjusted to account for any hazards.
Crownover said well water sampling is part of the process. His company will take well samples and analyze them for a variety of substances. In response to a question from the audience, he said that if vibrations were to cause any issues with a well, it would result in a change in chemistry and would be detected in subsequent testing.
Inspections, including photos and video, also will be done to document the condition of structures in the area.
Following the survey, peak particle velocity testing will be done to determine safe parameters for using vibrators mounted on specialized trucks. In town, Weems plans to use vibrators to conduct the seismic survey; in areas away from structures and roads, the company will utilize “shot holes,” which will be drilled using equipment moved into location by helicopter.
“Vibra-seis trucks are designed for an urban environment,” Crownover said.
A baseplate on the truck is lowered to the ground, and vibrations are then sent into the ground.
“The energy travels into the subsurface, much like a rock in a pond, and the ripples spread through the subsurface,” Land said.
Crownover said that the intensity of the vibrations will be kept well below the threshold at which cosmetic damage — cracked drywall, for example — would be likely. He said the vibrations from the trucks are less intense than those generated by typical road construction equipment.
Next comes the recording/vibrating phase of the project. Small charges will be detonated in the shot holes away from town, and the trucks will be put into action in town. The vehicles will be used in a group of three, stopping at predetermined points to conduct a “sweep,” then raising their baseplates and moving forward to the next point.
Geophones will be spread out over the 25-square-mile area to record the data. That information is then downloaded to computers, rendering a 3D map of the area’s geological structures. A cable-less geophone system is being used, so pods of geophones will not need to be linked via cables.
Land said seismic monitoring equipment would be in place for about four weeks.
The last step, Land said, is clean-up — removing all the recording equipment, as well and any markers used during the process.
“Once we’re gone, I want to see everything the way it was when we arrived,” Land said.
Addressing concerns from the audience, Land said the initial letter sent to landowners could have been written better. He said it asked for information not pertinent to the Kenai Loop project, such as Social Security numbers, because parts were taken from agreements used in other parts of the country, where landowners sometimes are paid a “nuisance fee” for crossing their land. He said he would serve as landowners’ point of contact for any damage claims.
The presentation can be viewed online at www.buccenergy.com. Navigate to “Alaska Operations,” and click on “Kenai Loop Seismic Survey.”