防返吐保压候凝挤堵封井管柱

The backflow-preventing pressure-holding curing squeeze stripper pipestring

对于套损、套窜严重的井,采用目前油田使用的光油管挤注管柱和部分油田使用的单封保护上层挤堵下层管柱,已无法控制堵剂的去向,若候凝时间掌握不好,在起钻时可能出现堵剂返吐,挤堵效果差,同时可能会污染保护层。为此,研制了一种防返吐保压候凝挤堵封井管柱。该管柱由可钻插管封隔器和井下机械开关组成,能实现封隔器下入、坐封、丢手以及堵剂挤入一趟管柱完成,满足地层高压挤堵剂和带压起钻不返吐的施工要求。现场试验表明,该管柱能够用于油水井下部层段堵水堵漏主层上返归位、封堵地层侧钻更新套管、报废井眼填充封井等措施施工中,满足高压挤堵封窜和带压起钻不返吐的施工要求,为老油田挤堵封井工艺提供了技术支持。

As for wells with serious casing damage and channeling,adoption of the blank tubing squeeze pipestring currently used by oilfields or the lower layer-blocking upper layer-protecting single-packer pipestring used by some oilfields cannot control the fate of blocking agents.If the curing time is not dealt with well,the backflow of the agents may arise in pulling out,the squeeze effect will not be desirable and meanwhile the protection layer may be polluted.Therefore,a kind of backflow-preventing pressure-holding curing squeeze stripper pipestring was developed.The pipestring consists of the drillable tube packer and the downhole mechanical switch.It can achieve the packer's tripping-in,setting and release,as well as blocking agent entry in one trip,and satisfy the operating requirement of the formation high-pressure squeezing agent and pressurized pulling-out without backflow.The field test shows that the pipestring can be applied to such operations as dealing with the main layer of water plugging and lost circulation to return upward to the original place in the lower intervals of the oil-water well,renewing the sidetracking casing in the plugging zone and filling and capping abandoned boreholes,providing the technological support for the squeeze hole-closure in old oilfields.