钻具防堵旁通阀

By-Pass Valve

  PTF通阀是用于复杂地层中喷射钻井和钻开油气层前，将该阀接在靠近钻头的钻柱处。在钻井过程中，当需要往井内替入稠泥浆或重泥浆，以及特殊作业，因钻头水眼堵塞而无法解堵时，该阀可提供有利帮助解堵的一种新型井下随钻工具。

During drilling operation, when well kick is taken place and bit bore is blocked. The by-pass valve can be opened to go fluid circulation and well killing. Before drilling in flow gas formation, the by -pass valve shall be located near or on the bit. When take place well kick and pump pressure is too high or blocked, the following steps can be taken to open the by-pass valve:

•     Discharge Kelly and drop in a steel ball (or a Nylon ball) which is carried by tool;

•     Connect with Kelly;

•     Put ball into retainer by pump circulation;

•     When fluid is closed, the shear pin can be sheared off with adding 0.5~1.5Mpa

pump pressure than original pump pressure;

•     After pin is sheared, the seal sleeve move down to open the discharge hole and

pump pressure come to drop down , then normal circulation and well killing operation can be started.