Knowledge of reservoir rock wettability is crucial for the understanding of fluid displacement mechanisms and for adopting feasible solutions to enhance oil recovery. Highly sensitive to the strength of fluid–rock interactions, nuclear magnetic resonance (NMR) measurements are a well-suited candidate for in situ wettability determination. Changes in correlation coefficients between NMR porosity \(\left( {\phi_{\rm NMR} } \right)\) and transverse relaxation time \(\left( {T_{2} } \right)\) can be used as a diagnostic parameter to determine in situ wettability. This paper aimed to take advantage of this promising feature to specify the downhole wettability of an oil well running through two carbonate reservoirs. In this regard, the correlation coefficient between \(\phi_{\rm NMR}\) and \(T_{2}\) was first computed at each depth. As a superior technique in analyzing nonstationary signals, the wavelet transform was then applied to the correlation coefficient log to remove shale content. Finally, the wavelet transform was re-applied to the modified correlation coefficient log to derive the detail coefficients. Scrutiny of the detail coefficients revealed a strong correlation with experimental wettability results. The results obtained from this investigation indicated that positive detail coefficients are associated with water-wet, and negative ones with oil-wet media.

储层岩石润湿性的知识对于理解流体驱替机制和采用可行的解决方案来提高石油采收率至关重要。核磁共振（NMR）测量对流体-岩石相互作用的强度高度敏感，因此非常适合用于现场润湿性测定。NMR孔隙率\（\ left（{\ phi _ {\ rm NMR}} \ right）\）和横向弛豫时间\（\ left（{T_ {2}} \ right）\）之间的相关系数变化可以用作用于确定原位润湿性的诊断参数。本文旨在利用这一有前途的功能来确定穿过两个碳酸盐岩储层的油井的井下润湿性。对此，之间的相关系数首先在每个深度计算\（\ phi _ {\ rm NMR} \）和\（T_ {2} \）。作为分析非平稳信号的一种高级技术，然后将小波变换应用于相关系数测井以去除页岩含量。最后，将小波变换重新应用于修改后的相关系数对数，以得出细节系数。详细系数的仔细检查显示与实验润湿性结果有很强的相关性。从这项研究中获得的结果表明，与水湿润相关的正细节系数，与油湿润介质相关的负细节系数。