Development of hollow water regulator free from casing and fishing and its application

At present,more than 800 orbital hollow water regulators are used in Shengli Oilfield each year.Because the well is dirty and its pressure is negative,the reversion of the regulators is ineffective and waterflooding cannot work as usual during the process of field operation.As a result,the pipe string has to be pulled out,which does not only increases the operation cost but also prolongs the operation cycle.Based on analysis,it is found that the main cause of the problem is that the downhole operation of mechanical structures is not reliable.ZKP hollow water regulator free from casing and fishing is successfully developed on the basis of converting mechanically controlled structures into hydraulic ones,preventing pistons from surpassing water injection holes while setting,and making the waterflooding pistons work using spring elasticity after releasing pressure.Dead cores do not need to be cast and fished while setting packers.This is favorable for simplifying the procedures for completing leak-proof strings of compression packers,reducing operation cost,and enhancing the operation quality and efficiency.The regulator developed has been applied to 354 wells so far,with the success rate and the interval qualification rate reaching 98.7% and 87.2% respectively.