Novel PDC drill bit for improving rock-breaking efficiency based on impact effect

Abstract

The invention relates to a novel PDC drill bit for improving the rock-breaking efficiency based on the impact effect and belongs to the fields of oil and gas drilling engineering, mine exploiting, geological drilling, tunnel engineering, tunnel engineering, tunnel shield, non-excavation and the like. According to the invention, the balling-up phenomenon or the stick-slip phenomenon generated during the drilling process of the hard and soft staggered formations in the prior art can be avoided, and the defects of low breaking rate, short service life and the like are overcome. According to the technical scheme of the invention, a blade shaft is arranged at the end port of a drill bit, and the lower end of the blade shaft enters a shell to be connected with a driver of the same transmission ratio via a shaft coupling. The driver of the same transmission ratio is then connected with a speed reducer. The output end of the driver is connected with a drive shaft via a magnetic coupler. The drive shaft is connected with a cam disk by a flat key. A connecting rod mechanism is connected with the cam disk and the lower end thereof is connected with a centre pinion via a spherical hinge. According to the invention, the longitudinal displacement of the centre pinion is realized, so that the intake amount of a core part is changed. Meanwhile, the breaking rate of the drill bit in soft and hard formations is increased, and the phenomena of balling-up, stick-slip and the like are reduced. Therefore, the well drilling cost is lowered.

Description

technical field [0001] The invention belongs to the field of technical equipment such as oil and gas drilling engineering, mining, geological drilling, construction engineering, tunnel engineering, shield tunneling and non-excavation, and relates to a novel PDC drill bit for improving rock-breaking efficiency by using impact action. Background technique [0002] In the process of oil and gas field development, the speed and efficiency of drilling determine the speed of oil field development. During the drilling process, the conventional roller cone bits and PDC bits often experience sticking and stick-slip phenomena, causing the drill string to be tightened and then suddenly released, resulting in severe vibration of the drill string and resulting in low rock-breaking efficiency of the drill bit. The main reason for the sticking and stick-slip phenomenon of the drill bit is not that the drilling pressure of the drill bit is not enough, but that the rock has strong tensile an...

AI Technical Summary

Problems solved by technology

During the drilling process, the conventional roller cone bits and PDC bits often experience sticking and stick-slip phenomena, which cause the drill string to be tightened and then suddenly released, resulting in severe vibration of the drill string, resulting in low rock-breaking efficiency of the drill bit

The main reason for the sticking and stick-slip phenomenon of the drill bit is not that the drilling pressure of the drill bit is not enough, but that the rock has strong tensile and compressive resistance, and the increase in the axial pressure of the drill bit does not significantly damage the rock, resulting in low rock breaking efficiency.

Therefore, many scholars at home and abroad have studied the use of rotary percussion downhole tools to increase the rock-breaking rate of the drill bit, but they can only provide the axial impact force of the overall drill bit, and cannot solve the phenomenon of mud balling and stick-slip of the drill bit well. To solve this problem, It is necessary to change the structure of the conventional drill bit and develop a new type of PDC drill bit with the longitudinal adjustment function of the central tooth

[0003] Due to the complexity of soft and hard formations, the loss of the drill teeth of the conventional PDC bit will increase during the drilling process. When entering the soft formation, the conventional PDC bit will appear mud bumps. time, the rock will increase the destructive force on the teeth

Therefore, different types of PDC bits can achieve better drilling efficiency in the same formation, but when encountering soft and hard formations, their drilling efficiency and life will be greatly reduced

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