钻柱振动信号特征及多次波成像

钻柱是连接地面和井底钻头及地层的通道,伴随着钻头旋转破岩产生的钻柱振动包含丰富的信息,通过分析在钻柱顶端采集的钻头振动信号能够获得钻头、钻具的工作状态以及所钻地层甚至钻头前方地层的岩性、地层压力等信息,进行井下诊断和钻前预测.钻柱是由具有不同横截面积的单元组成,截面变化引起的波阻抗差异使钻头振动信号沿钻柱传播时发生多次反射,形成钻柱多次波.利用单边反褶积自相关等方法对井场采集的钻柱振动信号进行了处理,得到了振动信号的特征、反射界面多次波成像和振动信号沿钻柱的传播速度以及钻柱的实际转速等,并与理论结果吻合较好,为钻柱振动录井和随钻地震技术研究打下了基础.

Features of drill string vibration signal and multiples imaging

Drill string is the medium connecting the formation and ground. Its vibration stimulated by the rotary bit contains a lot of useful information. It is possible to get the drill tools’ working condition and information of the formation that is drilled and will be drilled by analyzing the drill-bit vibration propagating in the drill string. Because different units of drill string have different cross section areas, the drill-bit vibration signal is reflected on the interface of changing cross section areas. By processing the drill string vibration signal with one-side deconvolved autocorrelation method, drill string image and drill string wave velocity are obtained. They match with the theoretical result very well. This provides a valid basis for the future drill string vibration logging and seismic while drilling (SWD) technology.