Abstract: The development of low-permeability reservoirs offshore faces significant challenges such as high costs, high risks, and high requirements. Large-scale fracturing technology based on fracturing vessels enables continuous and efficient reservoir stimulation, representing a key pathway for the economical and effective exploitation of offshore low-permeability oil and gas resources. Taking the "Haiyang Shiyou 696" fracturing vessel as an example, which enables continuous stimulation at a rate of 12 m$^{3}$/min and can increase fracture half-length by 1.5 times compared to conventional offshore fracturing, the recovery factor increased by approximately 5.0 percentage points. Through a comparative analysis of hydraulic jet fracturing, pumping bridge plug-perforation combined fracturing, and cemented sliding sleeve fracturing: it is concluded that the cemented sliding sleeve fracturing, with a non-operating time accounting for only 10%~15%, offers superior operational continuity and is best suited for the high-efficiency mode of fracturing vessels. Furthermore, key supporting technologies have been developed, including a seawater-based integrated variable-viscosity fracturing fluid system, continuous proppant supply, casing tie-back and downhole safety control. A multi-method fracture monitoring approach is also recommended to enhance post-fracturing evaluation accuracy. The research findings provide systematic technical support for the large-scale development of China$'$s offshore low-permeability oil and gas resources and the achievement of the "fewer wells and higher production" objective.

Key words: offshore, fracturing vessels, horizontal well, variable viscosity fracturing fluid, staged fracturing