Key technology for sand control tubing fishing in offshore oilfields

The current sand control tubing fishing technology has less consideration for the effects of the cutting position, well inclination and bottomhole assembly on the cutting operation. This research focused on two key points of fishing sand control tubing—cutting and milling and identified the cutting positions of the hydraulic mechanical cutting tool. The force on cutters during cutting was calculated, the factors affecting cutting were investigated, and the key technology for milling of sand control tubing was clarified. The research showed that with well inclination less than 12°, extra drill collars are required to improve the BHA rotation stability; with well inclination of 12°−55°, the reduction of cutting pressure, increase of drill collars, and prolonged cutting time should be adopted; with well inclination above 55°, it is required to reduce the cutting pressure, decrease drill collars, and place extra centralizers or torque reducers to improve the cutting power. Over 60 sand control tubing fishing operations using the presented technology were performed in the Liaodong, Bonan, and Boxi blocks of the Bohai Bay oilfield, which greatly enhances the fishing efficiency of sand control tubing and well intervention time-efficiency.