气测录井井深异常预警与校正的可行性

Feasibility of warning and correction on gas logging abnormal depth

气测录井中基于误差扰动的井深异常跳动现象是客观存在的,如果能找寻到一个函数,用于有效地模拟井深随时间的变化规律.那么就可以建立以模拟函数为基础的井深异常点预警控制系统并显示异常井深点。作为数据处理和编制函数表的常用工具.拉格朗日二次插值法和最小二乘法能有效地模拟已知井深与时间点。拉格朗日二次插值法可插值确定未知点,该法适用于获得两个已知点之间的井深一时间值;而最小二乘拟合函数法适用于对某一钻进过程进行实时不间断模拟和预测未知值。以某煤层气普查项目地质参数井的实测数据为对象.分别应用两种方法进行分析.通过设置时间误差阈限判断出时间点井深异常,以此为基础建立的井深异常预警控制系统.既可以对异常点进行报警.又可有效校验并更正井深一时间数据。

In gas logging,there is an objective existence of the well depth anomaly based on error disturbance,if a function can be found,which can effectively simulate the relationship between well depth and time,warning and control system can be set up for abnormal well depth based on the analog function and abnormal well depths can be showed.As common tools for data processing and compiling function table,Lagrange quadratic interpolation method and least square method can effectively simulate the fixed well depth and time points.Lagrange quadratic interpolation method can be interpolated to determine the unknown point,this method is applied to obtain depth and time values between two known pointss and least squares fitting method is suitable for realtime and continuous simulation and predicting unknown values for a drilling process.Taking the measured data of geologic parametric boreholes from a coal-bed gas reconnaissance project as the object,the two methods were applied to analyze,the anomaly between two well depths was reflected by setting two well depth threshold values.Based on this analysis,the warning control system for well depth anomaly was established,it not only can warn the abnormal points,but also effectively check and correct the depth and time data.