利用NMR技术判识混油钻井液条件下钻遇的油层

摘要

The use of oil-mixed drilling fluid application may potentially affect the discovery of oil layer, as well as the results of chromatography or spectrum surface logging. To study and quantify how the use of oil-mixed drilling fluid would affect the results of logging, high-resolution NMR surface logging while drilling technology was used to measure T2 spectrum and oil content with different levels of oil added into the drilling fluid. The results indicated that oil-mixed drilling fluid exhibited properties of oil in water, and could not blended with the oil layer. As a result, the T2 spectrum showed two independent peaks of oil. It is concluded that the oil layer can be identified accurately with the use of oil-mixed drilling fluid. In addition, by using the normalization method or external standard method, it was shown that the oil content of layer oil can be calculated in the drilling fluid. Field experiments were used to confirm the results of laboratory experiments.%混油钻井液对色谱、光谱录井技术发现和评价油气层带来了严重影响。为了准确识别和定量评价混油钻井液条件下所钻遇的油层，创新采用高分辨率核磁共振录井技术随钻检测钻井液T2谱及其含油率的变化。不同油品在钻井液中的混合实验结果表明，混油钻井液为水包油乳液，两种不同的油品在钻井液中难以混合，在T2谱上呈现相互独立的峰，据此可以直观、准确地识别所钻遇的油层；并可根据归一法、外标法定量评价钻井液中的地层油含油率。经现场应用，取得了与室内实验相一致的效果，证明了该项技术的有效性。