by negative mud pulses using a pressure relief valve between drill pipe and annulus

Full Title

Survey of boreholes or wells > Means for transmitting measuring-signals or control signals from the well to the surface, or from the surface to the well, e.g. for logging while drilling > using acoustic waves > through the well fluid > by negative mud pulses using a pressure relief valve between drill pipe and annulus

Classification Context

Section:

FIXED CONSTRUCTIONS

Class:

EARTH OR ROCK DRILLING; MINING

Subclass:

EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS