Application of self-excited oscillation pulsed jet in Ya 945 well, Yumen Oilfield

Silurian formation is buried deeply in Yumen oilfield，combined with the high compaction and high pressure loss, it is difficult to bring the high-pressure-jet advantage into play, thus the average ROP in deep section is hardly to reach 1m/h. So research is conducted on how to change the conventional jet effect, enhance the rock-breaking efficiency, lower the flowrate coefficient, and form instantaneous underpressure. The results show that the self-excited oscillation pulsed jet lowers flowrate coefficient to 0.6-0.8 by transforming the continuous jet current into instantaneous current, greatly strengthening the cleaning work in bottom hole. It has been used for the drilling of during Silurian formation of Ya 945 well at the depth of 304.86 m. With the average ROP being up to 1.73 m/h and improving 49% compared with offset wells, new breach for speed promotion in deep well drilling has been found in Yumen area.