基于2D-DCT变换的MWD遥传信号泵冲干扰消除方法

A Pump Noise Canceller for MWD Telemetry Signal Based on 2D-DCT

遥传技术是随钻测量(MWD,measurement while drilling)系统中的一项关键技术,目前大多数MWD系统均采用泥浆脉冲方式进行数据传输。钻井现场噪声环境复杂,特别是泥浆泵的泵冲干扰,其强度较大,如果其频率落入脉冲信号的带内,则会对地面接收信号造成严重干扰。因此若不能对脉冲信号带内的泵冲干扰进行很好的抑制,则会限制遥传系统对各种工况的适应能力。提出了一种基于二维离散余弦变换(2D-DCT)的泵冲干扰消除方法,该方法将地面接收到的一维泥浆压力信号转换为二维信号,然后进行2D-DCT变换,从而能在变换域进行泵冲干扰的消除处理。

The telemetry technology is a core technology for measurement while drilling （MWD）, and at pres- ent, the mud pulse is used by most of the MWD telemetry system. The environment noise at the drilling field is very complex, particularly the mud pump noise. The magnitude of the pump noise is large, and if its frequency is inside the bandwidth of the telemetry signal, it will cause serious interference to the received signals on the ground. Hence, if the in-band pump noise cannot be suppressed, the ability of the telemetry system adapted to various working condition will be limited. A pump noise cancellation method based on two-dimensional discrete cosine transform （2D-DCT） is presented. One dimensional mud pressure signal received on ground is converted to two-dimension, and then the 2D-DCT transform is performed. In the transform domain, the pump noise can be cancelled.