Detection of Weak Signal-to-Noise Ratio Signal While Drilling Based on Duffing Chaotic Oscillator

In the process of drilling, the strong vibration and rapid rotation of bottom drilling tools lead to multi-frequency and high-amplitude interference signals in attitude measurement signals. The problems of weak original signal amplitude and very low signal-to-noise ratio are always the technical difficulties in the field of while-drilling measurement. To solve this problem, a Duffing chaotic system detection method suitable for weak signal recognition while drilling is proposed in this paper. Firstly, the frequency reconstruction of downhole measurement signal is realized by scale transformation, and a weak signal detection model based on variable-scale Duffing oscillator is established, so that the measured signal meets the restriction of frequency parameters of this method. Then, in order to solve the influence of initial phase of measured signal on the accuracy of detection model, different periodic driving forces are introduced. The Duffing equation is solved to get the detection model of all-phase coverage measurement signals. Finally, the simulation results of the laboratory vibration platform system show that the signal-to- noise ratio of weak signals detected by this method can be as low as -20dB, which provides a new solution for the detection of strong vibration weak signals while drilling.