碳氧比测井钙质校正方法研究及应用

为了研究地层中的钙质对碳氧比测井含油饱和度解释结果的影响，针对大庆地区的地质条件，利用MCNP蒙特卡罗方法建立了脉冲中子全谱测井仪(PNST)的数值模拟模型，研究不同钙质含量、孔隙度、含油饱和度条件下碳氧比（C/O）和俘获Ca产额的变化规律，建立钙质对含油饱和度解释影响的校正方法，给出适用于大庆地区的碳氧比测井钙质校正公式，并将校正后的剩余油饱和度解释结果与取心结果对比。对比分析结果显示，经过校正的解释结果与取心结果符合度更高，表明该钙质校正方法能有效提高含油饱和度的解释精度。

Study and Application of Calcium Correction for C/O Logging

Calcium can bring interpretation difficulties to the remaining oil saturation, and it should be corrected in the practical application. In order to study the influence of formation calcium on interpretation of oil saturation with carbon/oxygen logging, a numerical model is set up using Monte Carlo method to simulate net inelastic and capture spectra measured by the Pulsed Neutron Spectral Tool (PNST) in a typical-size cased well in Daqing oilfield. The model is verified by the comparing the simulated results and the formation parameter simulation wells logging data. Variations of C/O and capture Ca yield under different calcium content, porosity and oil saturation are simulated, a correction method of calcium influence on interpretation of oil saturation is established, and a correction formula is deduced accordingly. The logging interpretation of a logging well in Daqing oilfield is compared with the coring analysis, it can be found that the corrected result has the higher conformity with the coring analysis. It shows that the correction method can eliminate the calcium effects and improve the interpretation accuracy of oil saturation.