Abstract Field X is one of the hydrocarbons producing fields in the Kutai Basin which is one of the largest and deepest tertiary basins producing the second largest hydrocarbon production in Indonesia with 2.47MMBO oil reserves and 28.1 TCF gas. Based on qualitative analysis, the target zone in the four wells is estimated to be within the range of 1050 – 1400 ms. Sensitivity analysis was employed to determine the most sensitive parameters capable of distinguishing lithology within the formation. To ascertain the optimal number of attributes to be used, linear regression was employed, resulting in the selection of 12 attributes with a correlation coefficient of 0.919. Concurrently, log data was utilized for electro facies analysis. Electro facies analysis involved interpreting the shape of the gamma-ray curve, which indicated that the deposition setting in the four wells resembled a delta system. Additionally, rock typing was employed to classify rocks based on wet clay shale parameters, yielding information about the direction and more detailed settings of deposition. The results from the multi-attribute method, rock typing, and electro facies analysis, it was determined that Field X was deposited in a tidal delta to delta front environment, with a deposition direction from North to South.