Wide-tooth cone composite drill bit

Abstract

The invention discloses a wide-tooth cone composite drill bit, and belongs to the technical field of drilling equipment in petroleum and gas, mine engineering, building foundation engineering construction, geology, hydrology and the like. The wide-tooth cone composite bit comprises a drill bit body, a fixed cutting structure and at least one cone. The cone and the fixed cutting structure are arranged on the drill bit body. The fixed cutting structure is provided with fixed cutting teeth. The cone is connected with the drill bit body through a bearing structure in a rotating mode. Cross-embedded teeth are embedded and fixed in the cone. A value range of a deflection angle alpha of the tooth top of each cross-embedded tooth is 70 degrees <=|alpha|<= 90 degrees, and an outline of the cross section of the embedded and fixed part of each cross-embedded tooth is non-circular. A novel cone structure is adopted by the wide-tooth cone composite drill bit so that the cone is stable in working, and the drill bit is good in working stability. Compared with an existing composite drill bit, the wide-tooth cone composite drill bit is higher in rock breaking efficiency, and meanwhile service life of the drill bit teeth and the bearing is prolonged, and therefore the service life of the drill bit is prolonged.

Description

technical field [0001] The invention belongs to the technical fields of drilling equipment such as petroleum and natural gas, mining engineering, building foundation engineering construction, geology, hydrology, etc., and specifically relates to a composite drill bit. Background technique [0002] The drill bit is a rock-breaking tool used in drilling engineering to break rock and form a wellbore. Roller cone bits and PDC bits are commonly used bits in drilling engineering. The tri-cone bits currently used in drilling engineering include steel tooth drill bits (also known as milling tooth drill bits) and carbide tooth drill bits (also known as insert tooth drill bits). The steel tooth drill bit is directly milling the cutting teeth on the cone body. The teeth have low strength and poor wear resistance, and are generally used in soft formations; Tungsten carbide teeth (hereinafter referred to as cemented carbide teeth or teeth), the hardness and wear resistance of cemented ...

AI Technical Summary

Problems solved by technology

The three-cone bit mainly breaks rocks in the form of impact crushing, that is, the teeth break rocks by impacting, squeezing and scraping with a small amount of slippage on the rocks. The disadvantage is that the energy utilization rate is not high and the rock breaking efficiency is relatively low. Low, and during the working process of the drill bit, the impact on the bearing is large, and the dynamic load coefficient is large

Because the cone breaks rock by impact crushing, the up and down vibration generated during the working process of the cone will directly affect the working stability of the PDC fixed cutting structure, resulting in the following adverse consequences: First, the impact load brought by the longitudinal vibration is easy Causes damage to the PDC teeth and shortens the service life of the drill bit; secondly, the longitudinal vibration will cause frequent changes in the depth of the PDC teeth in the fixed cutting structure. In severe cases, it may even cause the PDC teeth to frequently leave the bottom of the well. Reduce the rock breaking efficiency of the drill bit

In addition, the roller cone on the composite drill bit still breaks rock by impact crushing, and the working condition of the roller cone bearing is similar to that of the tri-cone bit, resulting in a short working life of the bearing, and the working life of the bearing has a great impact on the overall life of the drill bit. obvious constraints

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