T The "X" oil field is the working area of the KSO Pertamina EP - SE BWPMeruap located in the South Sumatra Basin. This research is specifically focusedwithin the Air Benakat Formation. This study uses facies and stratigraphicsequences by applying basic correlation method, calibration and analysis, whichwill give results in the form of (1) Determination of facies and lithology (lithofacies,electrofacies) (2) Determination of marker / sequence stratigraphy corelation (3)Depositional environment isopach mapping(4) Paleogeographic sequences andcross section that represents each ongoing chronology of each depositionalenvironment within. The data used in this study includes integration of 6 well logsdata, 1 drilling core data, 1 Side Wall Core (SWC) data.Interpretation of depositional environments, and sequencestratigraphical markers on oil field “X”, "HJ" stratum, among others, aredetermined by analysis of well log data. In the study area, the lithology obtainedconsisted of sandstone, shaly sand and clay stone which was obtained byelectrofacies log analysis carried out by six well logs and core obtaining lithofacies.Gamma ray log patterns are crucial for determining facies within the “HJ”stratum, dominant log patterns consists of serrated, bell shape, funnel and blocky.Based on the associations obtained, the depositional environment in the "HJ"stratum consists of the upper shoreface, middle shoreface, lower shoreface,estuarine channel and tidal mudflat. Along within the parasequence in the studywas divided into two (2) parasequences.