I’ve just returned from my second annual visit to the Offshore Technologies Conference (OTC) in Houston, Texas, a trade show for the offshore “hydrocarbon” industry.
As I indicated in my 2010 report, “Bigger than Texas” this event is gargantuan. They anticipate 90,000 attendees this year from around the globe – up 20,000 from last year’s final count. This is just a bit under the population of Burbank, California, giving us some indication of the vitality of the business.
My interest of course is noise. Typically offshore oil Exploration and Production (E&P) noise impacts are associated with seismic airgun surveys. And while these are problematic, seismic surveys are only one element of the noise contribution through the entire E&P process. Field development and construction, exploratory drilling, underwater acoustic communication, equipment placement, and sea-floor processing all generate their own particular noises. And given that offshore fields are expanding world-wide, their contribution to overall ocean noise is expanding as well.
But given the variability of environmental conditions, the reach of all of these noises would be hard to predict. Some wellhead “chokes” mediate multi-phase materials (oil, gas, brine, and sand) under many thousands of pounds of pressure. These may scream or roar. Others may mediate liquids only under a few hundred pounds of pressure. Knowing about this helps us strategize how we should monitor and quantify the noises.
A source of noise that is easy to predict comes from what are called “semi-submersible” drilling platforms. Deeper water operations preclude building bottom-mounted platforms, so floating, semi-submersible, thruster-stabilized platforms are used. The thrusters used are huge turret-mounted propellers, up to eight per platform. All of the turbulence in the attached picture is from these thrusters, which can stabilize a surging platform to within a meter on the x, y, and z axis.
Given the noise of just two smaller propellers on a cargo ship, four or even eight larger ones are likely to be quite nasty.
It is said that most of the “easy oil” is gone. This is driving oil E&P into more costly, difficult, and risky settings. Give the array of noises these offshore operations generate, the settings are likely to be more biologically expensive as well.