Interpretation and Reconstruction of Depositional Environment and Petroleum Source Rock Using Outcrop Gamma-ray Log Spectrometry From the Huai Hin Lat Formation, Thailand

Gamma ray logs are most useful in identifying subsurface lithology and interpreting depositional environments. This study highlights the use of outcrop gamma-ray along with observations total organic carbon (TOC) analysis to provide stratigraphic framework organic-rich rocks Huai Hin Lat Formation central Thailand. The reveals five sedimentary facies including (1) structureless sandstone, (2) structured (3) interbedded sandstone siltstone, (4) mudstone siltstone (5) calcareous mudstone. These can be grouped into two associations; mudstone-dominated sandstone-dominated associations. environment was interpreted as lacustrine basin-fill subdivided deep sublacustrine fan associated turbidity currents. gamma-log characteristics closely related lithologies controlled primarily by clay mineral compositions. Whist, spectral reveal more details on environments conditions. In this study, U concentrations is proven highlighting low K Th concentration successions due its ability fixed minerals materials under an anoxic condition. Thus, gamma suggested combine conventional log for recognition rocks.