pdc drill bit, method for determining the helical angle of its chip flute, and drilling method

Abstract

The invention provides a PDC drill bit, a method for determining the helical angle of the chip flute and a drilling method thereof, wherein the method for determining the helical angle of the chip flute of the PDC bit includes obtaining the rotational speed and drilling displacement of the drilling tool; obtaining the PDC The body diameter of the drill bit and the maximum diameter formed by all blades; obtain the cross-sectional area ratio coefficient of all chip flutes of the PDC drill bit; according to the obtained drilling tool speed, drilling displacement, body diameter, maximum diameter, and cross-sectional area ratio The ratio coefficient and the preset angle model are used to obtain the helix angle of the chip flute. The invention can avoid the hard contact between the drilling mudstone cuttings and the side wall of the chip removal groove of the drill bit, reduce or prevent the mud balling of the drill bit while realizing the efficient discharge of the drilling cuttings, and improve the drilling efficiency of the PDC drill bit in the mudstone formation.

Description

technical field [0001] The invention relates to the technical field of oil and gas geological drilling, in particular to a method for determining the helical angle of a chip flute of a PDC drill bit, a PDC drill bit and a drilling method. Background technique [0002] PDC drill bit (polycrystalline diamond compact drill bit) is an integrated structure, the whole drill bit has no moving parts, mainly consists of body, crown, hydraulic structure (water eye or nozzle, runner or chip flute), gauge block and cutting teeth It consists of five parts. Due to the advantages of high ROP and long service life, it has been widely used in major oil fields in recent years. However, when PDC bits are drilled in mudstone or formations with high shale content, mud bag problems are prone to occur. PDC bit mud balling is often accompanied by: 1. Squeeze phenomenon, resulting in early damage to the brittle PDC composite sheet; 2. Ineffective flushing and sufficient cooling of the chip teeth, ...

AI Technical Summary

Problems solved by technology

However, PDC bits are prone to mud bag problems when drilling in mudstone or formations with high mud content

PDC bit mud balling is often accompanied by: 1. Squeeze phenomenon, resulting in early damage to the brittle PDC composite sheet; 2. Ineffective flushing and sufficient cooling of the chip teeth, resulting in early damage to the drill bit teeth, affecting drilling efficiency, and even in serious cases. 3. The cutting teeth cannot effectively eat into the rock, which greatly reduces the rock-breaking effect of the PDC bit, seriously restricts the drilling speed, and increases the drilling cycle and drilling cost.

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