互相关函数法在定位射孔深度上的应用

油气井射孔深度校深技术是保证油气井完井精确射孔作业的前提。射孔作业利用油气井储层的自然放射性伽马校深和油套管接箍传统校深方法，随着油气开采时间延长，井下伽马放射性的减弱和油套管接箍的破损，射孔校深测量的这两路信号往往被井下噪声煙没，有效信号特征不明显，直接依靠传统的幅度识别法，会带来较大的射孔精度误差，甚至造成误射孔事故的发生，已无法满足薄储层精确深度射孔的需求。基于信号互相关函数法计算原理，将标准的接箍信号和伽马信号与射孔校深采集的对应信号进行互相关运算，压制背景噪声，突出有效信号，实现射孔精确校深的目的。现场应用表明，该方法校深技术简单，能够满足现场一次作业实现实时校深和射孔完井的目的，具有一定的实际应用价值。

Application of Cross Correlation Function Method in Locating Perforation Depth

Perforation depth correction technology for oil and gas wells is a prerequisite to ensure accurate perforation operations for oil and gas well completion. Perforating operations use the natural radioactive gamma correction method of oil and gas well reservoirs and the traditional depth correction method of tubing and casing joints. With the prolonged oil and gas production time, the downhole gamma radioactivity is weakened and the tubing and casing joints are damaged. The two signals of the depth calibration measurement are often obscured by downhole noise, and the effective signal characteristics are not obvious. Directly relying on the traditional amplitude identification method will bring about large perforation accuracy errors and even cause accidental perforation. It cannot meet the demand for precise deep perforation of thin reservoirs. Based on the calculation principle of the signal cross-correlation function method, the standard hoop signal and gamma signal are cross-correlated with the corresponding signals collected by the perforation depth calibration to suppress background noise, highlight the effective signal, and achieve the purpose of accurate perforation depth calibration. Field application shows that the method is simple in depth calibration technology, can meet the purpose of real-time calibration and perforation completion in one field operation, and has certain practical application value.