随钻测井系统泥浆脉冲影响因素研究及故障诊断

Research to Influence Factor of Mud Pulse of LWD System and Fault Diagnosis

以无线随钻测井系统工具(MWD、LWD、旋转导向等)泥浆脉冲信号为研究对象,在分析泥浆脉冲器结构、原理以及信号传输过程的基础上,推算出信号衰减的主要因素,并结合现场施工经验总结出可能造成解码失败的各类干扰因素,最终归纳出一套针对泥浆脉冲信号解码故障的诊断方案。该方案通过观察压力波形图的微弱变化把故障进行分类,再根据转子转数、泵压、泵冲等参数的变化规律以及泥浆性能、返砂和水龙带抖动等综合信息逐步缩小影响因素的范围,快速准确地确定故障原因。经现场实践,参照该方案可以解决现场98%的解码故障。

This paper takes mud pulse signals of LWD,including MWD,LWD and geo-steering as the research object.Based on analyzing the structure and operating principles of mud pulsar and the process of signal transmission,it deduces the main factors of signal fading.Considering all kinds of interference factors that may cause decoding failure coming from field experience,we fi-nally sum up a set of failure diagnosis scheme for mud pulse signal decoding which has been used in engineering practice.This scheme initially categorize the failures by observing the changes of pressure wave,and then gradually conform the possible influence factors according to the variation law of RAP,pump pressure,pump strokes and the integrated information of mud performance,re-turn sad,hose jitter level.Finally the problem can be identified quickly and accurately,and 98 per-cent decoding failure can be confirmed by the scheme.