Development and Application of the Downhole Drilling String Shock-Absorption and Hydraulic Supercharging Device

Table 3

Comparison of speeds into siltstone in adjacent well intervals.

Speed comparison	Drilling method	Well depth/m	Lithology	Speed/m/h	Speedup comparison/%
Test interval	PDC + downhole shock-absorption and hydraulic supercharging device	1848–1966	Granule, siltstone, psephitic sandstone; (with more than 60% gravel)	1.44	+80%
Comparison interval	PDC + Power-V	1674–1678	Psephitic sandstone; (with around 30% gravel)	0.8