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), report offshore energy.
Oilfield fracturing technology
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 monopolised 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.
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.
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.
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 metres, a beam of 22 metres, and a depth of 9.9 metres, 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.
Moreover, this vessel adopts an integrated power station design, as the fracturing equipment is highly integrated with the ship’s electricity consumption.
In addition, the vessel can perform fracturing operations under the environmental conditions of level 7 wind, 3-metre 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.
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.
CSSC’s Shanghai Shipbuilding Research and Design Institute further elaborates that the ship is furnished with a fracturing system command centre 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, realises automatic pressure adjustment, displacement distribution, and health detection, and effectively improves the operational efficiency of the entire system.
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Source : offshore-energy