Research and Application of Fracturing Technology for Offshore Oil Well

The fracturing technology for offshore oil well is developed to improve productivity of oil well, in view of the difficulties such as low natural productivity, poor operation condition, high requirements of safety and environmental protection for fracturing stimulation, and the inapplicability in offshore Chengbei oilfield of DG but effective technologies on land. In this paper, the research and development of new high-efficiency backflow and non-organometallic ion high temperature cross-linked agent were carried out, and the safe and environmental high temperature fracturing fluid suitable for offshore oil well was prepared with the special equipments and the safe operation technology being equipped for offshore fracturing. And finally the fracturing technology for offshore oil well was formed after using the three-dimensional fracturing software to optimize the process parameters and preparing the operation specifications of offshore fracturing. The fracturing technology was carried out through adopting non-dynamic positioning ships with wind resistance of no less than force 8 winds, and the operation equipments were fixed by welding. The layout on the ship deck meets the stability calculation requirements. The developed environmental high temperature resistant fracturing fluid does not contain methanol and can withstand temperature 165 ℃. The surface tension of the gel-out liquid is 20.7 mN/m and the interfacial tension is 0.24 mN /m. The 3D fracturing software was used to simulate and optimize the viscosity, operation scale and displacement of fracturing fluid system, and the strings with hydraulic pump was adopted, the maximum daily oil production reached 59.3t after fracturing for 17 Wells, with an average production increase being 13.5 times. The successful breakthrough of this technology has realized the large-scale application of fracturing in offshore oil wells, which provides the main technical model for upgrading and efficient development of Chengbei low-fault stage reserves.