Analysis of Drill String Whirling Characteristics Based on Near-Bit Measurement Data
The displacement signal of drill string vibration is difficult to be obtained in the actual drilling process. To further understand the vibration characteristics of drill string when whirling motion occurs in wellbore during drilling process， first， the near-bit checking tool was used to acquire the...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | zho |
| Published: |
Editorial Office of China Petroleum Machinery
2025-07-01
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| Series: | Shiyou jixie |
| Subjects: | |
| Online Access: | http://www.syjxzz.com.cn/en/#/digest?ArticleID=4977 |
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| Summary: | The displacement signal of drill string vibration is difficult to be obtained in the actual drilling process. To further understand the vibration characteristics of drill string when whirling motion occurs in wellbore during drilling process， first， the near-bit checking tool was used to acquire the vibration acceleration during rotary drilling of a deep well， and then the error control algorithm was used to conduct secondary integration for the vibration acceleration signal in the frequency domain， so as to obtain the displacement signal of vibration. Finally， by means of analyzing the vibration displacement characteristics of drill string at the time of whirling motion， combined with the rotation and revolution coupling effect of drill string and the position of the drill string relative to the wellbore， the measured “half frequency whirling motion” phenomenon was taken for example to explain the vibration laws of the drill string during forward and backward whirling. The research results show that for the measured downhole acceleration signal， the integration error of low-frequency segmentation can be effectively suppressed by introducing an error control equation in the frequency domain integration process and setting an expected target accuracy. When whirling motion occurs， the amplitude of tangential and normal vibration acceleration curves is more than 4 times that of normal drilling， and the amplitude of vibration displacement curve is about 10 times that of normal drilling， showing obvious periodic fluctuations. The fluctuation period is affected by the rotation and revolution coupling effect of drill string； the fluctuation period of tangential displacement curve of backward whirling is generally smaller than that of forward whirling， and the backward whirling is more severe than forward whirling. However， in the drilling process， affected by cutting of formation by bit and friction between drill string and wellface， forward whirling and backward whirling may occur alternately， and the forward whirling and backward whirling cannot be judged only by the period of vibration displacement signal. The research results have a guiding role in describing the vibration characteristics during whirling， judging the occurrence of whirling， and taking measures in time to eliminate the whirling and alleviate fatigue of drilling tools. |
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| ISSN: | 1001-4578 |