春晓气田泥岩垮塌测井数据校正及应用

Calibration of logging data from mudstone washout intervals and its application in Chunxiao Field

由于存在部分泥岩井眼垮塌,东海春晓气田测井曲线砂泥岩阻抗部分叠置。针对这一现象,采用未垮塌段泥岩伽马与密度拟合关系校正垮塌段泥岩密度,声波时差经本区伽德那公式拟合后求取。通过泥岩垮塌测井数据校正前后对比、直方交会、岩石物理、正演及反演效果分析,认为校正后的测井数据比较真实地反映垮塌段扩径泥岩地层特征,储层与围岩波阻抗差异明显,为储层反演、砂体空间展布分析提供了有力依据。

P-impedance is partly superimposed in sandstone and mudstone in Chunxiao field due to hole washout at part of mudstone intervals. To solve this problem, the mudstone density at hole washout intervals is calibrated with the regression relationship between GR and density at washout intervals, and the interval transit time at washout mudstone intervals is calculated through matching with Gardner formula of the study area. Though comparison of logging data before and after calibration, and analysis of cross plot, rock properties, modeling and inversion results, it is believed that the characteristics of washout mudstone can be reflected in calibrated logging data. P-impedance differences are obvious between sandstone and mudstone, which provide reliable information for inversion and analysis of sand body distribution.