鉆具防堵旁通閥

By-Pass Valve

  PTF通閥是用于復雜地層中噴射鉆井和鉆開油氣層前，將該閥接在靠近鉆頭的鉆柱處。在鉆井過程中，當需要往井內替入稠泥漿或重泥漿，以及特殊作業，因鉆頭水眼堵塞而無法解堵時，該閥可提供有利幫助解堵的一種新型井下隨鉆工具。

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.