A drill pipe float valve, also recognized as a non-return valve, is a specialized valve installed in the bottom hole assembly (BHA) and its primary function is to serve as a check valve, permitting the downward flow of drilling mud through the drill string but preventing any unwanted fluid from flowing back up into the drill string.
[pdf] One of the most significant advancements to reduce costs for drilling multiple horizontal wells from a single surface location or pad is the “walking” rig. A walking rig is self-propelled because it can move short distances (10 metres) without being disassembled and with pipe in the derrick.
[pdf] One of the most significant advancements to reduce costs for drilling multiple horizontal wells from a single surface location or pad is the “walking” rig. A walking rig is self-propelled because it can move short distances (10 metres) without being disassembled and with pipe in the derrick.
[pdf] 
