Method for monitoring wear state of shaft bottom drill bit during drilling

Abstract

The invention provides a method for monitoring a wear state of a shaft bottom drill bit during drilling. The method is characterized by comprising the steps that (S1) torque and axial force borne by the drill bit are measured by a first sensor and a second sensor; (S2) the torque and the axial force borne by the drill bit and measured by the first sensor and the second sensor are converted into digital signals; and (S3) relative changing amounts of the torque and the axial force are computed according to the digital signals, and whether a warning signal needs to be sent out is judged according to the relative changing amounts. According to the invention, the wear state of the shaft bottom drill bit can be monitored in real time; a working state of the drill bit can be analyzed and judged; and the warning signal is sent out when the relative changing amounts of the torque and axial force borne by the drill bit exceed preset thresholds.

Description

technical field [0001] The invention relates to the technical field of real-time monitoring of drill bit wear in oil, mining, geological exploration and other industries, in particular to a method for monitoring the wear state of a bottom hole drill bit while drilling. Background technique [0002] Reducing the cost of drilling has always been the most critical issue in oil and gas exploration, and how to effectively control the cost of drilling bits is an important factor in the control of drilling costs. PDC bit (Polycrystalline Diamond Compact bit, polycrystalline diamond compact bit) is a drilling tool commonly used in the oil drilling industry. It is expensive. If it is not used enough, it will cause a lot of cost waste, and the PDC bit is not found in time after it is worn out. If it is still overused, not only will the drilling time be reduced, but more seriously, drill bit accidents will occur, causing property and even casualties. Therefore, how to detect the status...

AI Technical Summary

Problems solved by technology

PDC bit (Polycrystalline Diamond Compact bit, polycrystalline diamond compact bit) is a drilling tool commonly used in the oil drilling industry. It is expensive. If it is not used enough, it will cause a lot of cost waste, and the PDC bit is not found in time after it is worn out. If it is still overused, not only will the drilling time be reduced, but more seriously, drill bit accidents will occur, causing property and even casualties. Therefore, how to detect the status of the drill bit in time and improve the utilization rate of the drill bit has become a key factor to save drilling costs.

[0003] The root of PDC drill bit wear is that the cutting teeth on the drill bit are damaged, resulting in insufficient cutting force. When the number of damaged cutting teeth increases to a certain extent, the drill bit needs to be scrapped

Therefore, at present, the research on the wear of PDC bit is based on the mechanical analysis of a single cutting tooth, and it is basically based on laboratory experiments and theoretical analysis, and the possible wear of the drill bit by the formation is predicted purely from the perspective of mechanical calculation.

This kind of analysis and research cannot actually monitor the real state of the drill bit on site. Therefore, the driller still needs to rely on the measurement results of wellhead torque, drilling time, pump pressure, etc., and rely on experience to judge whether the drill bit is worn and to what extent. The technical level of drillers is high, and the misjudgment rate is high

As we all know, due to the high temperature and high pressure environment during the drilling process, the drill pipe will actually be twisted into a twisted shape when it rotates downhole, so there is a large error between the measured value of the torque at the wellhead and the actual torque value at the drill bit, which increases the probability of misjudgment

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