PDCdrill bit for rock breaking by thermal spalling

Abstract

The invention provides a PDCdrill bit for rock breaking by thermal spalling. The PDC bit comprises a drill bit body and fixed blades, and PDC teeth, water holes or nozzles are formed in the fixed blades; the PDC drill bit is characterized in that one or more electromagnetic wave generators are arranged on the blades of the drill bit, each electromagnetic wave generator comprises a direct current power supply, an RLC circuit, a high-frequency amplifier and a transmitting antenna, a central water hole is formed in the center of the drill bit, and the drill bit is a steel body bit. In this way, arock is irradiated and heated by electromagnetic waves, and broken by thermal spalling, under the high temperature state, the rock is suddenly cooled when being exposed to water through the central water hole, since the temperature inside the rock changes rapidly, a temperature gradient is formed inside the rock, and the thermal fracture or thermal impact phenomenon occurs in the rock and causesdeterioration of various mechanical properties of the rock; and the drill bit uses two modes of thermal spalling and scraping and cutting of the PDC teeth to break the rock in a coupled mode, thus therock breaking efficiency of the drill bit is improved, the difficulty of the PDC teeth entering the formation can be lowered, the service life of the PDC teeth is prolonged, and comprehensive performance of the drill bit is improved.

Description

technical field [0001] The invention belongs to the fields of oil and gas drilling engineering, mining engineering, building foundation engineering construction, geological drilling, tunnel engineering, hydrology and non-excavation and other technical equipment fields, and specifically relates to a PDC drill bit for thermal exfoliation and rock breaking. Background technique [0002] PDC bits rely on high-hardness, wear-resistant, self-sharpening polycrystalline diamond compacts (referred to as PDC teeth or cutting teeth) as cutting elements to shear and break rocks. PDC drill bits have high mechanical penetration rate, long service life and low drilling cost in soft to medium hard formations, so they are widely used in the drilling of oil and gas wells. [0003] In oil and gas drilling engineering, the geological conditions of the formation are often very complex. Under the pressure of the overlying formation and high-density drilling fluid, the mud shale and argillaceous s...

AI Technical Summary

Problems solved by technology

These complex formation conditions can easily lead to abnormal failure of the PDC bit, or make the drilling effect of the bit worse under special drilling conditions. It is difficult to meet the current drilling needs only by mechanical rock breaking

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