The Study On The Cutter's Abrasion Rule Of PDC Coring Bit

In order to decrease cutter's abrasion of PDC coring bit, PDC (Polycrystalline diamond compact) was used to abrade rock in the lathe as PDC coring bit cutting rock on the academic analysis. By the experiment, the effect on PDC cutter's abrasion rule where the cutting angle, the height of protrusion, the linear velocity and rock's indentation hardness were made was researched. Under the same stress, same rub distance, five different groups of cutting angle, six different groups of height of protrusion, five different groups of linear velocity and five different kinds of rock, PDC cutter's abrasion volumes were measured respectively. The Finite Element Method software ANSYS was used to analyze stress distribution in rock. And the results were all verified by the field experiment.The main conclusion is that:(1) In order to decrease the PDC cutter's abrasion volume as far as possible, when the cutting angle of PDC coring bit is 10°or 15°, 2.00mm is the optimal height of protrusion. When the cutting angle is 20°,25°or 30°,3.00mm is the optimal height of protrusion. And 5°is not recommended to be the cutting angle.(2) In order to decrease the PDC cutter's abrasion volume as far as possible, the cutting angle should be designed to be 10°, when the height protrusion is 1.50mm; the cutting angle should be designed to be between 10°～15°, when the height protrusion is 2.00mm; the cutting angle should be designed to be 20°, when the height protrusion is 2.50mm;and the cutting angle should be designed to be 30°, when the height protrusion is 3.00mm or 3.50mm.(3) The PDC cutter's abrasion volume and the linear velocity are in direct proportion during drilling.(4) The PDC cutter's abrasion volume is in inverse proportion to indentation hardness.(5) When the indentation hardness of rocks is larger, bigger cutting angle of PDC coring bit should be designed.(6) When the cutting angle is enlarged, the effective-stress of cutter will be decreased.