关键词: 油基钻井液, 储层, 地化录井, 三维定量荧光, 核磁共振, 显微荧光薄片, 准噶尔盆地, 南缘区块

Abstract: In the southern margin block of Junggar Basin, oil-based drilling fluid has been more and more widely used in stabilizing the borehole wall, preventing formation water sensitive expansion and improving the drilling speed with its good lubricity and inhibition. Oil-based drilling fluid has a great impact on traditional mud logging, especially on the identification of fluorescence display in rock cuttings. Geochemical logging technology, 3D quantitative fluorescence technology, NMR technology and microfluorescence thin section technology are of great significance for the identification of oil-gas shows, oil property judgment and fluid property identification under the water-based drilling fluid condition, but they are greatly affected under the oil-based drilling fluid condition. In order to eliminate or reduce the influence of oil-based drilling fluid on mud logging and obtain reliable mud logging interpretation and evaluation conclusions, a series of mud logging technology identification means are summarized on how to accurately identify the strata oil-gas shows under the oil-based drilling fluid condition. The later oil testing results show that the discovery rate of oil-gas shows is up to 100%, the accurate rate of fluid property discrimination is 100%, and the accuracy of interpretation and evaluation is 77.78%. This method provides a reliable basis for the effective identification of hydrocarben reservoir by mud logging technology under oil-based drilling fluid condition.

Key words: oil-based drilling fluid, reservoir, geochemical logging, 3D quantitative fluorescence, NMR, microfluorescence thin section, Junggar Basin, southern margin block