Pressure impulse generator for use in drilling operations, allows transfer of significant pieces of debris via central orifice in the rotor without damaging rotor

摘要

An orifice (44) in the center of a rotor (43) communicates with an orifice (41) in the center of a stator (40) to allow debris to pass through without damaging the rotor blades. The communicating section (48) varies between a maximum and a minimum section as a function of the position of the rotor and part at least of the section is in the center of the rotor-stator assembly : The communicating section varies in a sinusoidal manner. The stator and rotor orifices each have a central portion in the middle of the stator or rotor respectively and at least one lobe connected to the central portion. The central portion is circular and the lobe is a circular sector or section of a trapezium. The number of lobes on an orifice helps determine the period of the pressure impulses. At least one of the orifices is a central rectangular. The pressure impulses are sinusoidal when the rotor turns at constant speed. At least one of the orifices is cruciform and the amplitude of the pressure impulses is determined by the difference between the maximum and minimum sections. The rotor as it turns applies a continuous force to the debris in the fluid to push it towards the communicating section. Independent claims are also included for a diagraphy tool or a tool for measuring during drilling containing an impulse generator as above; and a telemetry system containing an impulse generator as above.