Anti-Collision Optimization Design Technology for Large-Scale Infill Drilling for Cluster Well Groups in the Artificial Island of the Bohai Sea

When infill wells were drilled and massively upscaled within cluster well groups in the artificial island B of the Bohai Sea,it was difficult with low efficiency in the design of anti-collision and obstacle-bypassing systems.According to the analysis of the overall anti-collision situation and characteristics of the infill wells,the data of previously drilled wells were accurately calibrated;the principles for cluster well group platform optimization and anti-collision design which were specified in the industrial standard were used to formulate the specific workflow for anti-collision trajectory design in order to massively upscale the infill wells,and thus form an overall optimal design method and optimized the drilling sequence,slot matching relations,as well as anti-collision trajectory design parameters.Through multiple rounds of slots adjustment and trajectory optimization,trajectory design and anti-collision analysis were conducted in 45 infilling wells in a limited well platform space.The lowest separation coefficient values of all wells met the minimum limit of 1.5 specified by the industrial standard,and 70% of such values concentrated at more than 1.7,reducing the risk of borehole collision on the whole.The research results showed that the anti-collision optimization design technology can effectively solve the anti-collision design problem in large-scale infilling adjustment of well cluster groups,and improve the design quality and efficiency.