State approves Cook Inlet seismic survey

SAExploration plans offshore 3-D survey, west of the northern Kenai Peninsula using wireless nodes for recording seismic signals

Alan Bailey

Petroleum News

On March 18 Alaska’s Division of Oil and Gas approved a land use permit for SAExploration to conduct a 3-D seismic survey in the upper Cook Inlet. According to the approval notice the survey will take place in state waters west of the northern Kenai Peninsula. The survey area, encompassing about 821 square miles, will extend from the peninsula coast, between Moose Point and Nikiski, to the western coast of the inlet between West Foreland and the Chuitna River. The permit is effective from March 18, 2015, to March 18, 2016.

According to the decision document SAE plans to use wireless nodes placed on the seafloor for recording the seismic data, rather than towing hydrophone recorders behind a seismic vessel. Lines of receivers, parallel to the shoreline, will be spaced at 1,650-foot intervals. Two seismic source vessels will tow airguns along source lines perpendicular to the lines of receivers. Operations will take place over a series of 7.5-mile by 10-mile patches, with each patch taking three to five days to set up and shoot.

As each patch is recorded, the nodes from the previous patch will be retrieved and the data from the nodes downloaded into a computer system.

On March 20 the National Marine Fisheries Service issued a notice in the Federal Register, proposing the issuance of a marine mammal incidental harassment authorization for seismic surveying by SAExploration across a broad area of the upper and lower Cook Inlet between April 1, 2015, and March 31, 2016. The authorization proposal does not reference any specific surveys, merely stating that the company proposes to conduct 3-D surveys in the Cook Inlet over a period of 160 days during the specified time period.

“The exact location of where the 2015 survey will be conducted is not known at this time, and probably will not be known until spring 2015 when SAE’s clients have finalized their data needs,” the authorization says.

The authorization includes a description of SAE’s proposed operational technique almost identical to that in the Division of Oil and Gas permit document.

A company conducting an offshore seismic survey requires an incidental harassment authorization, to ensure that there is no infringement of the Marine Mammals Protection Act if a marine mammal is inadvertently disturbed during seismic operations. The closing date for public comments on the proposed authorization for SAE is April 20.