井口声发射井筒液气浸检测—时延估计方法

基于高阶统计,提出了井口声发射井筒液气浸检测中的接收和发射声信号之间时延估计的非参数化和参数化方法。通过分析声信号在井筒液中的传播过程,井口声发射井筒液气浸检测中的接收噪声,可近似模型化为空间相关的高斯色噪声。由于四阶累积量对任意高斯噪声的盲目性,因此,较常规互相关估计方法,这些方法可以进一步提高检测概率。计算机模拟结果证实了它们的有效性。

WELLHEAD ACOUSTIC EMISSIVE GAS INFLUX DETEC-TION: TIME DELAY ESTIMATION METHODS

Based on high order statistics, the non-parametric and parametric methods, which estimate the time delay between the receiving and emissive signal, are presented in wellhead acoustic emissive gas influx detection. By analyzing the signal propaga-tion process, it is seen that the noises, received by two pressure sensors can be modeled as spatially correlated Gaussian noise ap-proximately. The fourth order cumulant is blind to arbitrary Gaussian noise, so these methods may significantly increase gas influx detection probability compared to the conventional cross-correlation method. Computer simulation confirms their availability.