Experimental and Simulation Study of One-Piece High Working Layer Pregnant Diamond Drill Bit

Abstract

Aiming at the problem of low shear strength of diamond-impregnated bit with high working layer, poor ability to drill fluid cooling bit, and carrying rock powder, a one-piece high working layer diamond-impregnated bit was studied. The one-piece cutter design of the bit mainly uses internal and external strengthening to strengthen the strength of the single tooth between the teeth.  The simulation results show that the stress concentration area of the bit is in the root of the tooth and the internal and external strengthening between the teeth under normal working conditions. Under the same working condition, the maximum shear stress of the one-piece high working layer diamond-impregnated bit is 5.022×104Pa, which is lower than that of the conventional diamond-impregnated bit, which is 5.506×104Pa. The internal and external strengthening structure of the one-piece high working layer diamond-impregnated bit can effectively disperse the stress of the bit cutter, realize the integration of the bit and improve the overall performance of the bit. Through the gradual opening element and the internal and external strengthening coordination between cutters, the alternating type gradual opening structure realizes the gradual opening of the cyclic channel. The water-blocking structure forms a cantilever structure with a surrounding U-shaped groove. With the wear of the working layer in the drilling process, the water-blocking structure falls off and forms a new cyclic channel. When the pump volume is 32L/min, 47L/min, and 72L/min, the flow loss is 6.025%, 7.494%, and 9.206%. The test results show that the one-piece structure of the one-piece high working zone impregnated diamond-impregnated bit and the alternating gradually open cyclic channel can meet the requirements of conventional drilling. The service life of the one-piece high working layer-impregnated diamond-impregnated bit is 415m, which is 3.2 to 3.6 times longer than that of the conventional bit of the same size.

Keywords: one-piece, High working layer, Gradual opening cyclic channel, Diamond-impregnated bit