Blue Tarpon Well Stimulation Vessel, United States of America
Blue Tarpon is a fracturing and stimulation vessel designed to execute more than one ultra deepwater completion on a single sail. The ship can also perform pressure pumping, sand control, fracturing and acidising activities.
The vessel, measuring 91.6m long, is one of the largest stimulation vessels in the world. The beam of the vessel is 18.3m and draught is 7.3m.
Blue Tarpon was delivered in June 2011. She is the seventh stimulation ship in the fleet of Baker Hughes, an oilfield service company based in Houston, USA. North American Shipbuilding built the vessel in Larose, Louisiana.
The design was provided by Houston-based naval architecture and marine engineering firm Elliott Bay Design Group (EBDG). Certification from the American Bureau of Shipping (ABS) ensures the vessel adheres to stringent safety training and certifications.
Design of the well stimulation vessel
EBDG worked in close cooperation with Baker Hughes to deliver a design of the vessel that can provide stimulation treatments at high rate and high volume.
The designers also focused on reliability and efficiency of the vessel so delays and associated operating costs could be minimised. Maximum cruising speed of the vessel is 14.5kt and operational speed is 10kt. A total of 44 crew members can be accommodated onboard.
The stimulation plant is built in an enclosed structure to improve its reliability and protect it from environmental impressions such as corrosion.
Facilities and equipment of the Blue Tarpon
The vessel is equipped with three blenders to perform pressure pumping, sand control, fracturing and acidising operations. Large proppant and fluid carrying capacities allow the vessel to take on multiple well completions without returning to the dock to resupply.
The vessel is provided with greater safety systems and is incorporated with redundant back up blending and pumping capabilities to reduce the risks associated with high rate, high pressure ultradeepwater completions.
A fully redundant, DP (dynamic positioning) Class-2 control system incorporated in the vessel helps to automatically maintain her position and heading in the rough weather and sea conditions. The vessel also has a touch-screen control room from where the proportion of the addition of proppant and chemical additives is controlled automatically.
All equipment controls have been integrated and pressure pumping operations made easier by using a treatment control software application called EZTreat. Another software called JobMaster data acquisition displays data in real time after acquiring and processing it.
The vessel is also outfitted with a quality assurance / quality control (QA/QC) laboratory to facilitate quality control of fluid systems and chemical recipes.
Mixing / pumping capacity
Built to perform day-and-night operations in deepwater, the vessel has a maximum pump rate of 9.38m3 a minute, and proppant capacity of 952,544kg below deck and 340,194kg above deck. There are ten separate high-pressure pump units.
These pump units, erected in a fully enclosed structure, can pump up to 14,515kg of proppant a minute and deliver up to 24,000 hydraulic horsepower.
The blending rate is 15.9m3 a minute, maximum sand delivery rate is 14,515kg a minute and pneumatic sand delivery rate is 9,526kg a minute.
Wet chemical addition rate range is 1.13l to 181.8l a minute, while dry chemical addition rate range is 0.2kg to 11.3kg a minute. Maximum on-the-fly acid mixing rate is 3.8m3 a minute.
There are two liquid pumps, each with a pump rate ranging between 22.7l and 209.2l a minute. The vessel is also provided with two speciality additive screws with additive rate between 14kg to 2,268kg per minute per screw. A 38.1m3 hydration tank is also available.
Engine and propulsion power
Blue Tarpon is equipped with two Caterpillar main diesel engines, each of 3,600hp capacity. The twin bow thrusters (one of 1,675hp and another of 1,200hp Rolls-Royce swing-up CPP) and a stern thruster of 1,675hp enable the vessel to cruise in the widest possible weather and sea conditions.