Apache Deploying Wireless Seismic Technology in Alaska's Cook Inlet
Houston-based Apache Corp. has become the first producer to use true-cable free wireless seismic technology offshore Alaska to limit the impact of seismic activity on Cook Inlet's wildlife, communities and environment - including Cook Inlet beluga whales.
The use of wireless 3-D seismic is part of Apache's commitment to conducting 3-D seismic operations in Alaska's Cook Inlet "in ways that limit the impact on communities and the environment," the company said in a July 24 article on its website, addressing criticisms of its seismic program.
Apache is using true cable-free nodal recording systems, designed and manufactured by Sugar Land, Texas-based FairfieldNodal, in order to minimize the impact of its seismic survey on Cook Inlet's wildlife population and environment.
"Because we're shooting onshore and offshore, we have to go back and meld and blend the data for the different sections together," said Lisa Parker.
The company is using the technology for its ongoing 3D seismic survey of Cook Inlet, which will encompass onshore, offshore and the transition zone of Apache's acreage. The seismic survey will continue for the next two and a half years.
Source: Apache Corp.
After acquiring leases on 850,000 acres in Cook Inlet in August 2010, Apache began the permitting process for its seismic and exploration programs. In an effort to address concerns over the impact of seismic activity on local wildlife and the environment, Apache conducted a technology test to compare how traditional cable seismic would perform versus a wireless system.
Impressed with what it saw, the company initiated the permitting process to utilize wireless seismic and received approval to use this technology in the spring of 2011.
Approximately 1.4 billion barrels of oil was discovered in Cook Inlet in its early development in the 1950s and 1960s. Exploration and production in Cook Inlet declined after the discovery of Prudhoe Bay. Only a handful of fields have been discovered in Cook Inlet, but the field size distribution strongly suggests another 1.3 to 1.4 billion barrels of oil remain to be discovered in the Cook Inlet basin, Apache said.
Apache will begin drilling in Cook Inlet in October.
Source: Apache Corp.
Fairfield's product is truly cable free, unlike nodes from manufacturers who have elected to keep the power supply, electronics and sensor connected with short cables and connectors, said Roger Keyte head of marketing and business development at FairfieldNodal.
The nodes are placed on the ocean floor or buried onshore. Except for a rope tied to nodes placed offshore to retrieve them – the rope is not involved in the spacing of the node – the nodes have no cables, said Keyte.
Source: Apache Corp.
Marine nodes weigh 65 pounds and look like a 50-pound free weight, but are a bit thicker, said Lisa Parker, head of government relations for Apache in Alaska. Land nodes weigh 4.8 pounds and look like a two-pound coffee can with a spike on the bottom. Both types of nodes are made of plastic and stainless steel.
The nodes are retrieved after a period time and taken back to the office, where the data is downloaded and the nodes are recharged. The data is then forwarded to Apache's geoscientists for interpretation.
"Because we're shooting onshore and offshore, we have to go back and meld and blend the data for the different sections together," said Lisa Parker, head of government relations for Apache in Alaska. "It's like putting the pieces of a puzzle back together."
Source: Apache Corp.
Since 1924, traditional seismic systems have involved sensors connected to cables. These sensors transmitted signals back to a localized recording system to be converted into digits, said Keyte.
Using a system with heavy, cumbersome cables presents difficulties onshore and offshore, Keyte noted. Offshore, the cables mean seismic vessels can't get close to structures in the water such as rigs and platforms. Traditional systems also tend to be noisier.
Using cabled system onshore was especially problematic, with electrical leakages occurring due to animals biting or chewing the cables or sweat from the hands of workers, said Keyte.
Utilizing a true cable-free system cuts down on the amount of time crews spend troubleshooting to fix leakages. The cable free system increases the reliability of data and allows the recording time to be controlled.
Source: Apache Corp.
FairfieldNodal's cable-free system also minimizes the impact of recording seismic data on local wildlife and environment. The nodes, which integrate the hydrophone or geophone and battery, don't touch the environment versus the tons and tons of cable used with traditional cable seismic systems, said Keyte. Deploying nodes offshore for seismic surveys cuts down on the noise.
The cable-free nodes can be easily deployed from boats to place beneath offshore platforms. They also are not affected by tides, and work under tough conditions.
Alaska's Cook Inlet
The use of wireless seismic technology is part of Apache's plan to conduct marine seismic operations in Cook Inlet while minimizing its impact on Cook Inlet beluga whales and other local wildlife, which also include killer whales, harbor porpoises, Steller sea lions and harbor seals.
These efforts include conducting aerial surveys and using trained observers on vessels in an exclusion zone that extends approximately 6 miles (9.5 kilometers) from the seismic source vessel in order to prevent incidental encounters with protected marine animals.
Apache shuts down seismic source operations if a Beluga whale or other protected animal is spotted. The location and distance of the animals from operations, and the direction in which the animals are moving, are determined by the NMFS-qualified Protected Species Visual Observers (PSVOs) on board the vessels.
These observers are contractors paid by Apache, but with specialized skills and resumes vetted and approved by the NMFS, a company spokesperson told Rigzone.
Two PSVO observers, equipped with reticle binoculars and big-eye binoculars, are placed on board each support vessel, while others are assigned to an onshore station to monitor marine mammal activity. Reports from these observers are also filed weekly and monthly with relevant agencies.
A passive acoustic monitor is also deployed to allow PSVOs to listen for mammal activity after dark and in times of limited visibility.
Operations only resume when the mammals have left the area or not been observed for a designated period of time.
The 6-mile exclusion zone radius was established based on the results of acoustic testing in Cook Inlet by independent experts.
Critics of Apache's seismic program in Cook Inlet include former Remington Steele and James Bond actor Pierce Brosnan, who last month urged members of the Natural Resources Development Council to ask the Obama administration to halt Apache plans to use acoustic air guns for its Cook Inlet operations, saying it would be harmful to beluga whales.
A lawsuit was filed in May by the National Resources Defense Council, the Center for Biological Diversity, Center for Water Advocacy and Chickaloon Native Village, saying that the National Marine Wildlife Fisheries (NMFS) issuance of an Incidental Harassment Authorization for seismic surveys in Cook Inlet.
To date, Apache has not spotted any Beluga whales in the 6 mile zone while conducting seismic. Apache is allowed a certain number of encounters per species under its permits. The company has had seven encounters – or spotted – with harbor seas in the zone; the company is allowed 50 encounters. Apache has had one encounter out of an allowed 20 with harbor porpoises.
No sea mammals have been harmed as its seismic survey in Cook Inlet progresses, an Apache spokesperson told Rigzone.
Many sources of manmade sound, including large and small vessel traffic, aircraft, U.S. Army and Air Force military operations, as well as oil and gas drilling and construction activities such as dredging and pile driving, can disturb animals in Cook Inlet, an active marine area, Apache said in its July 24 article.
"The intensity of sound dissipates as it moves farther from the source because the sound spreads out and energy is absorbed by seawater," said Apache.
At 6 miles from the source, sound from a seismic source is less intense to a Beluga whale than the "clicking" sounds – or echolocation – emanating from another nearby whale.
The Alaska Fisheries division of NMFS determined - in its biological opinion - Apache's proposed seismic program would not likely jeopardize the continued existence of the Cook Inlet beluga whale or Steller sea lion populations, nor destroy or adversely modify the Cook Inlet beluga whale's critical habitat.
In studying the direct effects from noise on the Cook Inlet beluga whales, the Alaska Fisheries division determined that noise from airguns associated with Apache's seismic program may affect and is likely to adversely affect beluga whales in the action area. However, the seismic activity will be short-term and localized and will be mitigated through steps taken by Apache to reduce the effects of noise.
It was also determined that the vessel and aircraft noise associated with the seismic program may affect, but is not likely to adversely affect Cook Inlet beluga whales.
The biological opinion was undertaken to determine the impact on beluga whales of seismic activity noise, which involves high energy, low frequency sound in short pulse durations to determine substrates below the seafloor.
The noise associated with seismic surveys could potentially harass beluga whales, which use sound for communication and other life functions. In general, noise can impact wildlife by damaging hearing organs, resulting in a temporary or permanent hearing loss, altering behavior or even increasingly the mortality rate or prompting animals to abandon their habitat.
A sound source verification study conducted in September 2011 in Cook Inlet indicated noise from the onshore activity does not transmit into the waters of Cook Inlet at levels exceeding the NMFS acoustic harassment threshold for intermittent sounds.
According to the NMFS, the population of Cook Inlet beluga whales may have once numbered as many of 1,300. Between 1994 and 1998, the population declined 47 percent, from 653 to 347 whales, primarily due to subsistence hunting by Alaska Natives. The Cook Inlet beluga whale population has not recovered from that decline, the reasons for which are not known.
In January of this year, NOAA's Alaska Fisheries Science Center reported the Cook Inlet Beluga Whale population total 284 animals, nearly 20 percent lower than last year's estimate of 340.
NMFS sought to address the decline in Cook Inlet beluga whales by designating the species as depleted under the Marine Mammal Protection Act. The Cook Inlet Beluga Whale was also listed as an endangered species in 2008.
The National Oceanic and Atmospheric Administration (NOAA) designated critical habitat for the species in April 2011, enabling consultations to reduce negative impacts that federal or federally funded projects could have on the species recovery.
Development of a recovery plan is still underway for the species and continues to fund research on the species. The 2011 estimate of 284 is within the 10-year population range trend for Cook Inlet belugas, which shows an average annual decline of the population of 1.1 percent.
Scientists know that beluga populations are not capable of increasing more than 20 percent in a year, and believe the actual decline of 20 percent in a year would likely be reflected in a large number of reported mortalities, which the National Oceanic and Atmospheric Administration (NOAA) hasn't seen, the NOAA said in a statement.
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