Where is a drill pipe float valve used?
Drill pipe float valves are used in a length of drillpipe, drill rod, and other tubular products called the drillstring. This string of underground tools and pipes is used in drilling for oil, gas, and water, and in boring under-road and under-river crossings, for utility construction. Drill pipe float valves do not have threaded connections so they can not be screwed together like other downhole pipes and tools.
The float valve fits inside the drill string and a bore is machined for the valve in one of the drillstrings threaded connections. Where the pipes/tools are joined together (called a tool joint) the float valve fits snuggly in place, making sure the flow in the drillstring goes only one direction (downward or away from the drilling rig).
The float valve can be used anywhere from top to bottom of the drillstring. It’s most common location is in the BHA (bottom hole assembly) which includes the bit, and can include a bit sub, near bit stabilizer, other stabilizers, float sub, cross-over sub, mud motor (top sub), drill collar, and the drillpipe. Multiple float valves can be used in one string, although double stacking is not recommended because of possible damage to the float valve in high pressure situations. Instead, separate the valves in different tool joints.
