China enriches offshore oil & gas operations arsenal with its first and ‘world’s largest’ fracturing vessel
China is hard at work to bring its oil and gas self-sufficiency strategy to life in a bid to reduce its dependence on U.S. and European companies and ensure its energy security. To this end, a design scheme for – what is deemed as – the world’s largest and China’s first offshore oilfield fracturing engineering vessel, independently developed by Shanghai Shipbuilding Research and Design Institute (SDARI) of China Shipbuilding Group and tailored for the Tianjin branch of CNOOC, passed the basic design review of China Classification Society (CCS).
While offshore low-permeability oil and gas field reserves are an important potential reserve source for China’s offshore oil production, offshore oilfield fracturing technology has been monopolized by a few European and American countries for a long time, with China being unable to join the fray due to the lack of professional technology and equipment. Bearing this in mind, Shanghai Shipyard took the initiative to solve the issue by developing – what is said to be – the world’s largest and China’s first offshore oilfield fracturing vessel, making another contribution to the innovation and improvement of the country’s shipping industry offerings.
While fracking boats are a relative novelty, this type of ship is mainly used for the exploitation of potential reserves of offshore low-permeability oil and gas fields to achieve stable and increased production. When drilling activities are completed, the pressure at the bottom of the well exceeds the formation rupture pressure, and a series of gaps are artificially created in a certain range of the wellbore by injecting high-pressure acid – acidification fracturing – or sand-containing fluid (sand fracturing) into the wellbore, so that, the oil and gas in the reservoir can flow into the wellbore through these gaps and be extracted from the surface.
Furthermore, if there is no artificial crack, the fluid needs to overcome the resistance of the formation during the seepage process before entering the wellbore, but some wells have no capacity at all without fracturing because the energy is not enough to overcome this resistance. This is when a fracturing vessel comes in handy, as it can maneuver and flexibly sail to the target platform for fracturing operations, maximizing the control reserves, cumulative production, and overall recovery of single wells. For platforms with limited deck area, especially unmanned platforms, large-scale fracturing operations are no longer difficult with fracking vessels.
Taking into consideration all the benefits, China State Shipbuilding Corporation’s Shanghai Shipbuilding Research and Design Institute confirms that a relevant design and construction contract for this type of vessel has been signed, marking “a major breakthrough” in the field of fracturing technology and engineering in Chinese offshore oilfields, “breaking the long-term foreign technology monopoly and blockade in one fell swoop.” This highly integrated, automated, digital, fracturing vessel will be built at Wuhu Shipyard.
With a total length of 99.9 meters, a beam of 22 meters, and a depth of 9.9 meters, the vessel is expected to meet the new needs of large-scale fracturing operations, multi-well batch fracturing operations in China, as well as gas wells, and ultra-deep fracturing operations, and fill the gap in fracturing technology and engineering fields in the Asian country’s offshore oilfields.
Oil & gas fracturing vessel’s bells and whistles
In addition to professional fracturing equipment, CSSC’s Shanghai Shipbuilding Research and Design Institute explains that the ship is equipped with liquid supply equipment, mixing equipment, sand mixing equipment, sand storage and transportation equipment, other material storage and supply equipment, etc. in view of the special needs of offshore fracturing operations. The vessel’s professional equipment for oilfield production increase is arranged in the cabin in the main hull and can effectively reduce the impact of sea conditions while the ship’s critical fracturing equipment capabilities are believed to be among the best in the world.
Moreover, this vessel adopts an integrated power station design, as the fracturing equipment is highly integrated with the ship’s electricity consumption. The integrated power station distribution board is divided into five sections of busbars, and when the maximum single point of failure occurs, the ship power station can ensure that four fracturing pumps, one sand mixing device, and one mixing device work at full load, ensuring the safe development of fracturing operations.
In addition, the vessel can perform fracturing operations under the environmental conditions of level 7 wind, 3-meter wave height, and 1.5 throttling. The ship encompasses the form of all-electric propulsion, equipped with two electric propulsion full-swing thrusters, one telescopic thruster, and two bow thrusters. The dynamic positioning capability reaches DP 2 class, and the speed can reach more than 13 knots. The ship can also realize operations such as rotation and traverse in situ within a small radius with “superior” maneuverability, outlines Shanghai Shipbuilding Research and Design Institute.
Chasing greener shipping
The new fracturing vessel sports the electric propulsion closed ring annular closed busbar design, and the number of on-grid units can be adjusted according to the load of the whole ship’s power grid during DP operation, which improves the load rate of the on-grid engine unit and reduces fuel consumption and emissions. The vessel’s generator set has no light load working conditions, can maintain full load operation, and diesel engine efficiency is maintained at the best operating point to reduce diesel consumption and emissions while achieving green standards.
On top of this, the vessel is also equipped with a domestic sewage treatment unit that meets the latest regulations of the International Maritime Organization (IMO) MEPC to meet the emission control requirements. The ship is equipped with a service cloud platform with engine room, navigation, and integration platform functions, which realize the digital operation of equipment and intelligent operation of ships, making them more economical, safe, and efficient.
CSSC’s Shanghai Shipbuilding Research and Design Institute further elaborates that the ship is furnished with a fracturing system command center and corresponding professional control software in the configuration of the electrical system, which enables the monitoring and control functions of oilfield production increase equipment and other supporting equipment, realizes automatic pressure adjustment, displacement distribution, and health detection, and effectively improves the operational efficiency of the entire system.
Shanghai Shipyard is committed to serving China’s offshore oilfield exploration, exploitation, transportation, and other areas. China’s largest deepwater comprehensive survey vessel, Haiyang Shiyou 640, the country’s first deepwater environmental protection work vessel, Haiyang Shiyou 301, and many other high-end offshore key equipment, are enabling the Asian player to become “an innovation leader” in the field of marine engineering equipment research and development, underscores Shanghai Shipbuilding Research and Design Institute.