T This research was motivated by the complexity of the facies in the research area which was carried out for the development of wells in the research area. Three wells were used in this study which had Well Log data, Core data, and Mudlog data. Stratigraphic sequence analysis was carried out which interpreted that the Gumai formation was in the transgressive phase and the Air Benakat formation was in the regressive phase, the system tract results analyzed occurred in the Gumai formation having a TST system tract and in the Air Benakat formation starting with HST and ending with the Highstand System tract. The first 3 markers were obtained from the 2 formations MFS 1, SB 1, and MFS 2. The depositional environment of the Gumai formation is interpreted to be in the tidal flat transition depositional environment in the Subtidal subenvironment and the Complex Bar facies which is dominated by Bar Fringe. In the Air Benakat formation it is divided into 2 intervals, namely the lower and upper Air Benakat formations, in the lower Air Benakat it is interpreted as an intertidal depositional environment with sea influence sometimes with the Complex Bar facies which is dominated by Off-Axis Bars, at the top it is interpreted as a depositional environment intertidal with slight marine influence with the Complex Bar facies dominated by Axis Bars. Petrophysical calculations include Vshale and Porosity calculations where these calculations are related to the facies in each formation and depositional environment and the appropriate results are obtained, namely the Gumai formation has poor porosity, sufficient in the lower Air Benakat, good in the upper Air Benakat