钻柱振动录井技术的时频分析方法研究

Research on time-frequency analysis method of drill string vibration logging technology

为提取破岩时的有效信号,采用钻柱振动录井技术,通过在钻头后安装三分量加速度传感器采集破岩时的振动信号;分别采用短时傅里叶变换、小波变换、Hilbert-Huang变换等不同的时频分析方法,对数值模拟信号处理分析,以对比各种分析方法在时间分辨率、频率分辨率等方面的优缺点。通过比较不同的时频分析方法特点,采用短时傅里叶变换对贵州某矿的实采数据处理分析,结合时频信号在不同位置的特征来确定钻进过程中岩性变化的位置以及钻机不同工作状态的改变。研究结果表明:破岩较破煤时,200Hz以下能量比破煤的能量强5倍以上,400Hz和800Hz位置能量较破煤时更明显,破岩仍具有很强能量,破煤只能在对应位置看到极少量能量,800Hz以上破煤就无能量。钻机旋转未破岩在200Hz和400Hz都有很少能量,能量值不足破岩和破煤时的1%,钻机在水平进退钻时只存在10Hz以下原有钻机工作的固有低频。钻柱振动录井技术对岩性划分和钻机工作状态的确定可为实际矿井钻探提供有力技术支撑。

In order to extract effective signals during rock breaking,drill string vibration logging technology was adopted,and three component accelerometer was installed behind the drill bit to collect vibration signals during rock breaking.Different time-frequency analysis methods such as short-time Fourier transform,wavelet transform and Hilbert-Huang transform are used to analyze the numerical simulation signal processing to compare the advantages and disadvantages of various analysis methods in terms of time resolution and frequency resolution.By comparing the characteristics of different time-frequency analysis methods,it is decided to use the short-time Fourier transform to analyze the actual data of a mine in Guizhou,the position of lithology change and the change of working state of drilling rig are determined according to the characteristics of time-frequency signals in different positions.The study results show:when rock breaking is compared with coal breaking,the energy below 200 Hz is more than 5 times stronger than that of coal breaking.The energy at 400 Hz and800 Hz position of energy are more obvious,coal breaking can only see very little energy in the corresponding position,and coal breaking above 800 Hz has no energy.The drilling rig has little energy at 200 Hz and 400 Hz,and its energy value is less than 1%of that at breaking rock and coal.When the drilling rig advances and retreats horizontally,there is only the inherent low frequency of the original rig working below 10 Hz.The division of lithology and determination of drilling rig working status by drill string vibration logging technology can provide strong technical support for actual mine drilling.