金属磁记忆检测井下套管应力集中的研究

金属磁记忆技术可有效判断应力集中区,对套管的损伤进行早期诊断.利用铁磁材料的磁记忆性,研制井下在役套管检测系统.该检测系统依据采集的磁记忆信号,可准确地判断套管的应力集中区状况.设计了井下磁记忆检测仪的系统硬件结构,给出核心传感器电路的研制方案,保证仪表可靠性和高灵敏度;针对井下复杂的环境,数据处理方面采用中值滤波和自适应小波消噪方法,以提高磁记忆信号的信噪比.提出了新的特征量诊断方法,保证可靠地判断套管应力集中危险区域.通过实验验证该方法的有效性和可行性.

On Testing Stress Concentration Zone of Borehole Casing with Metal Magnetic Memory

Metal magnetic memory(MMM) technique is an effective method to find stress concentration zone,which can provide early diagnosis for casing damages.A downhole casing detection system has been developed according to MMM.The system collects the magnetism memory signal liberating from stress concentrating area,hence fast and correctly to judge the stress concentration zone.In this paper,the hardware structure of the system is introduced,and some significant sensor circuits are given with high reliability and sensitivity.Farther,the adaptive wavelet denoising method and data smoothing arithmetic are applied in testing systems with MMM,the data are reserved and the noises of the signal are reduced.The new character of magnetic signals is proposed to estimate stress concentration zone.Lastly,the validity and feasibility of the method are demonstrated by experiments.