Key technologies for offshore perforation of over kilometre horizontal wells
The difficulty of perforation operations in offshore horizontal wells exceeding one kilometers is high,and the safety of the operation faces enormous challenges.This paper takes the horizontal adjustment Well A3H of a bottom water gas reservoir with a perforation span of 1 066.2 meters in the East China Sea as an example.Firstly,the difficulties in perforating operation,such as failed burst propagation failure,large perforating impact load,post-perforating string sticking,perforating gun connection seal failure,and water control in ultra-long heterogeneous bottom water gas reservoir were analyzed.Based on this,the key technologies for perforation operations in ultra kilometer horizontal wells have been proposed.The first one is perforation parameter optimization technology,such as 89 mm thick wall directional perforating gun,after-effect composite perforating charge,changing hole density,horizontal upward angle of 60° quadrangular phase.The second one is pipe structure optimization technology,such as vibration absorption pipe,anti-settling buffer device,large diameter anti-withdrawal buckle explosion-transmitting joint,lifting and lifting load sensitivity and instantaneous detonation force calculation.The third one is perforation ignition process optimization technology,such as staged detonation,staggered peak setting delay ignition.Field application shows that this perforating scheme significantly reduces the risk of perforating operation in ultra-long Well A3H,and achieves the effect of initial water cut below 20％and initial production over twice.The research provides a reference for the development of low permeability gas reservoir with bottom water exceeding one kilometers.
offshoreover kilometer span perforationhorizontal well perforationdirectional perforationvariable pore density
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