基于井径变化的声波测井时差校正

环境因素，特别是井径的无规则变化，严重影响声波测井资料的可靠性，给声波测井资料的应用带来偏差。已有的各种校正方法在实际应用中或多或少受到一些限制，不能很好地消除由井径扩径引起的声波时差异常。为此，首先从理论上分析了声波测井仪器经过井径扩径段时的时差异常，得出测量时差随发射声系在扩径井段的位移出现规律性异常的结论；然后对比了同一口井中油基泥浆和水基泥浆的声波测井数据，实际测量结果验证了理论分析结果；最后提出了基于井径变化的时差补偿校正方法。实际处理结果表明，该方法能有效地消除井径扩径引起的声波时差异常。

Acoustic log moveout correction based on variation of borehole diameter.

Environmental factors (especially the irregular changes of borehole diameter) seriously affect the dependability of well logging data,which brings about some problems in application of acoustic log data.The existing correction methods have some limitations in actual application and so it cannot well correct the abnormality of moveout caused by the enlargement of borehole. First,the abnormality of moveout with sound wave logger passing the enlarged bore hole is theoretically analyzed,show- ing that there exists a regular change between the measured moveout and the displacement of injected acoustic system. Then,the acoustic logging data of oil base slurry and that of water base slurry in the same well are contrasted,indicating that the measured result is in good accordance with the theoreti- cal one.On the basis of this,the moveout offset correction method based on borehole diameter is proposed and used in practice,showing that the method can effectively remove the abnormality of acoustic moveout caused by hole enlargement.