Depositional environment characterization in deltaic system by utilizing core, well log and seismic attribute data, Northern Malay Basin

Abstract

The heterogeneity of shallow marine facies is quite hard to be solved. However, integrating all the data is essential to determine the details of facies distribution, whereas facies characterization is an important part that should be done before the petrophysical characterisation. This study aims to evaluate the reservoir depositional facies distribution using seismic well log and core data based on sequence stratigraphy concept, seismic interpretation, and seismic attributes, thus reducing the risk of oil exploration and improving the success rate. To ensure the objective is achieved, sequence stratigraphy interpretation has been done using integrating well log, core, and seismic data to identify the depositional environment. Distribution of coal helps to create well log correlation. Lithofacies and fluid have been interpreted according to core, test and log patterns, such as; gas sand, brine sand, shale, and coal. Based on the characteristic of logs, biostratigraphy and core data, five depositional environments have been interpreted in this study including in-distributary channel, delta plain (flood plain shale), crevasse splay, delta front shale (prodelta), and mouth bar. The interval of the target area is generally influenced by regression systems where on the lower formation is dominated by the transition depositional environment and changed to be dominant of delta plain.