Experimental Study On Impregnated Bit Wear By Hard Sandstone

The stratigraphic profile of the Junggar basin is complex,and the mechanical parameters of rock are wide range of differences,some of the rocks are of high hardness and abrasiveness.In these strata,the rock breaking efficiency of conventional cone bit is low,PDC bit is suitable for soft and medium hard formations,and impregnated bit is more suited for high hardness rock of Junggar basin.The paper select the right rock outcrops for laboratory experiment of impregnated bit by research on the geology and formation lithology of Junggar basin.Based on overall consideration of diamond concentration and hard particle content of matrix of impregnated bit,mechanical parameters of rock,drilling pressure and rotary speed etc.factors for the study.The research shows that: take the phenomenon of diamond appear threshing and matrix appear occlusal wear as standard,and come to conclusion that the 70% concentration of diamond is more suitable;take the phenomenon of passivation of diamond particles and wear of matrix as standard,come to conclusion that the 50% hard particles content of matrix is more suitable;and work out micro-impregnated bit based on the conclusion above,the experiment of micro-bit shows that the application of the impregnated bit drillability is feasible to the hard sandstone of Junggar basin.And there is a threshold bit weight during drilling.Compared with the effect of the increase of drilling pressure,the rotary speed of impregnated bit has a greater impact on mechanical drilling speed of impregnated bit;the wear of impregnated bit increased with the increase of drilling pressure,rotary speed and plastic coefficient of hard sandstone,and decreased with the increase of hardness,uniaxial compressive strength,elastic modulus and impregnated drillability of hard sandstone.Fitting and calculating the experimental data and come to regularities between factors and index coefficient of abrasiveness of sandstone to impregnated bit.And set up the life prediction formula of the impregnated bit.Put forward that it should improve the rotary as far as possible to improve the efficiency of rock breaking of impregnated bit,and lay foundation for the fast drilling and application of impregnated bit in hardness and abrasiveness stratum of Junggar basin.