Method and system for transmitting information in a jet drilling system

The present invention provides a method and an abrasive jet drilling system for transmitting information from a downhole location to a surface location. The method comprises: providing a jet drilling system, comprising a drill string extending from surface to a downhole location in a borehole; generating a fluid flow in the drill string, the fluid flow comprising a mixture of drilling fluid and a quantity of abrasive particles; obtaining information regarding a downhole condition; modulating the quantity of abrasive particles in the mixture in dependence of said information, to generate data pulses downhole; detecting said data pulses at surface; and determining a transmitted downhole condition based on the detected data pulses.