基于安全程控的双向锚定密封悬挂封隔器研制

为了满足水平井裸眼分段压裂工艺对悬挂封隔器的"下得去、挂得住、脱得开、封得住、提得出"的更高要求,研制了双向锚定密封悬挂封隔器。该悬挂封隔器由中心管、主体、双向锚定管柱机构、环形空间密封机构、定位球及控制阀组成,其主要技术特点包括:(1)该悬挂封隔器不但具有双向锚定管柱、密封环形空间的功能,而且还具有无需钻柱倒扣或者另设丢手工具就可以实现钻柱与悬挂封隔器分开的特性;(2)具有"只有投球后进液通道才能打开—悬挂机构坐挂—密封机构坐封—中心管解脱"联动程序的控制阀,避免了悬挂封隔器提前坐挂、完钻后钻杆无法解脱的问题,也确保了悬挂封隔器若未坐挂可应急提出整个管柱;(3)新颖的多级防退设计,提高了双向锚定管柱、环形空间密封的性能;(4)设计了具有在常规解脱失效时确保钻具提出的安全机构。地面模拟试验结果表明:所研制的双向锚定密封悬挂封隔器的双向锚定管柱、环形空间密封、安全起出钻柱等性能均达到设计要求。

Research and development of a suspending packer with bidirectional anchoring and sealing based on safety program

When open-hole staged fracturing of horizontal wells is carried out, the suspending packer should have the advantages of smooth running, fast hanging, convenient separating, good sealing and easy pulling out. In this paper, a suspending packer with bidirectional anchoring and sealing was developed to meet these requirements. This suspending packer is composed of central pipe, main part, bidirectional anchoring string mechanism, annulus seal mechanism, positioning ball and control valve. Technically, it presents the following characteristics. First, it can fulfill the functions of bidirectional anchoring string and sealing annulus, and separate the suspending packer from the drilling string without drill string backing-off or another releasing-tool setting. Second, it is equipped with the control valve with the linkage program of "opening the incoming fluid channel only after ball dropping, setting hanger mechanism, setting seal mechanism, and releasing the center pipe", so as to avoid the premature setting of suspending packer and guarantee the releasing of drilling pipes after drilling and the emergent pulling out of entire string in the case of failed setting of suspending packer. Third, the novel multistage anti-receding design improves the performance of bidirectional anchoring string and annulus seal. And fourth, the safety mechanism is designed to make sure that drilling tools can be pulled out in case of conventional releasing failures. The suspending packer with bidirectional anchoring and sealing was tested by performing ground simulation experiments. It is shown that its performance of bidirectional anchoring string, annulus seal and safe pulling out of drilling string can meet the design requirements.