Vol. 25, No.44 Week of November 01, 2020
Providing coverage of Alaska and northern Canada's oil and gas industry

KIC ANWR seismic

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Winter 2020-2021 plan eyes Dec. 31 mob., 848 sq. mi. in eastern 1002 area

Steve Sutherlin

Petroleum News

The Kaktovik IŮupiat Corp. has requested authorization for a 3D seismic acquisition program on the eastern portion of the Arctic National Wildlife Refuge Coastal Plain for the winter season of 2020-21.

A proposal and plan of operations for the survey, dubbed the Marsh Creek East Program, was released Oct. 23 by the U.S. Department of the Interiorís Bureau of Land Management.

The program area encompasses some 848 square miles, 542,592 acres in total, including 92,000 acres of KIC lands with Arctic Slope Regional Corp. subsurface ownership and 450,592 acres managed by BLM, the proposal said.

This winterís program is smaller than the Marsh Creek 3D survey earlier proposed by partners SAExploration, ASRC and KIC, which was to encompass the entire 2,600 square miles of the ANWR 1002 area.

Approval would authorize KIC and operator SAE to conduct operations once frost and snow cover are at sufficient depths to protect tundra - as identified in the 2020 Coastal Plain Leasing Record of Decision - continuing until tundra travel has been closed for the winter, the proposal said.

Analysis of the project includes access to the program area from Deadhorse, storage of fuel and a mobile camp capable of housing up to 180 people.

Mobilization is expected to start Dec. 31, after forward looking infrared radar surveys are conducted to detect polar bear den sites. Thermistors in and around Kaktovik will determine snow depth and appropriate soil temperatures prior to start of operations, the proposal said.

Camp trailers and seismic equipment would be transported along a preferred overland access route from Deadhorse to Kaktovik or via a secondary sea ice route. The tundra access route is 136.5 miles, versus 66.4 miles for the sea ice route. No ice roads are planned.

Before camp trailers and equipment enter the program area, advance survey teams using Tucker Sno Cats or low ground pressure vehicles would scout environmental conditions, such as snow depth and ice thickness and integrity, and map a trail for the main seismic crew and camp to follow, the proposal said.

The advance survey crew will verify, identify, stake and map avoidance areas such as environmental hazards, slopes greater than 10 degrees, Native allotments, cultural sites, river and stream crossings, and important habitat features including (but not limited to) polar bear critical habitat and den sites, seal lairs, grizzly bear den sites and sensitive willow areas.

The advance crew would use Sno Cats and/or snow machines equipped with ground penetrating radar systems to test ice thickness. Ice conditions would be checked with battery operated ice augers to verify the calibration of the GPR, measure ice depths on sea ice, or verify depths where GPR units cannot reach.

Sno Cats on advance ice check operations would be equipped with a handheld or vehicle mounted FLIR device to scan for potential polar bear dens.

Temporary airstrips approximately 75-100 feet wide and 2,300-3,500 feet long would be constructed on tundra and lakes, as necessary, to support seismic activities.

Aircraft would not operate within one half mile of polar bears and would remain 1,500 feet above ground level, except during landing and takeoff, and when required for safety reasons such as inclement weather, the proposal said, adding that aerial FLIR surveys for maternal polar bear den sites would be conducted below this altitude with U.S. Fish and Wildlife Service approval.

SDS with compressive sensing

Seismic acquisition would be source driven shooting (SDS) combined with a compressive sensing design, using rubber tracked/buggy vibroseis vehicles and wireless autonomous nodes/geophones, the proposal said.

Geophone receiver points with wireless nodes and a single geophone would be spaced along a receiver line perpendicular to source lines; and both source and receiver lines would be spaced approximately1,320 and 660 feet apart, respectively. Up to five receiver lines could be placed on the ground at one time.

SDS methodology allows for a single vibroseis vehicle to travel down a source line, reducing risk of compaction or damage to the tundra, and 12 vibroseis vehicles, spaced at least 1,320 feet apart, could collect data at the same time.

Lighter, smaller univibe vehicles (also used to conduct vibroseis) would be used in narrow riverbeds and on ungrounded freshwater ice, to reduce potential disturbance and reduce the risk of working in areas of ungrounded freshwater ice.

Univibes would only be used on lakes with ice greater than 36-inches thick. Nodal devices and geophones, however, can be placed on lakes and riverbeds with ice thick enough for Sno Cats.

Univibes could also be used on grounded sea ice.

Two univibe vehicles could collect data at the same time.

Vibroseis sampling frequency along source lines will be 27.5 feet, with duration and decibel levels of the source so low that hearing protection is not required for seismic crew members, the proposal said.

KIC plans approximately 6,459 miles of receiver lines and 3,237 miles of source lines. Receiver lines would be traveled twice - to lay out the receivers, and to retrieve.

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