Analysis on the reason of PDC bit delamination wear under the effect of hard particle

作者：Fuping Feng; Chi Ai; Haisu Xu; Fahao Yu; Zhihua Cui

来源：International Journal of Earth Sciences and Engineering, 2014, 7(5): 1751-1755.

• Alternating stress
• Contact Stress
• Delamination wear
• Hard particles
• PDC compact

The PDC bit damage or scrapping will happen when drilling in the formations with many hard particles, which restricts the increase of penetrate rate and the usage range of bits seriously. In this paper, the wear mechanism of PDC compacts under hard particles’effects is analyzed based on the wear character. Furthermore, the reasons of delamination wear, which happens under the condition of the hard particles slide contact with PDC compacts, are also obtained through analysis on the change rules of PDC compacts inner stress. The reasons mainly includes: (1) there exists a large tensile stress behind the contact indentation, which provides a power for the vertical crack producing. (2) The incompatibility of compacts interior deformation along the direction of bit movement can result in the formation of horizontal cracks. (3) The existence of shear stress inner PDC compacts can accelerate horizontal cracks extension toward surface. As a result, an exfoliate similar to “V”shape will be formed. (4) The surfaces of PDC compacts will bear the effect of alternating stress generated by the hard particles, which can decrease the breaking strength. Finally, the cracks inside PDC compacts become more easily formed.

• 出版日期2014