Application of Elemental Logging in Geological Determination of Strata of Jurassic in Dibei Area

The Jurassic in Dibei area is a set of terrestrial coal-bearing deposits, and the main reservoir is Ahe Formation. The great difference of pressure coefficients between the target bed and its upper and lower coal seam may lead to pressure differential sticking or malignant loss sticking. Therefore, the key to geological determination of strata is to accurately identify the top boundary of Ahe Formation. According to the analysis of the correlation between the content of elements in cuttings and minerals, the paper establishes the discriminant criteria of sandstone, mudstone and coal seams based on single well, and key layer determination methods (such as curve characteristics, sandstone element characteristics) are summarized. Field application shows that not only lithology identification is more accurate, and the determination for the top boundary of Ahe Formation is better. Relying on XRF element logging technology, lithology can be identified quickly and accurately, which has certain promotion and application value.