The researchers studied the Sandakan Formation in East Malaysia to understand its sedimentology, depositional environment, and reservoir quality. They examined two outcrops and identified eight different types of sedimentary facies. Clean and massive sandstone was found to have good sorting and high permeability, making it a good reservoir. In contrast, interbedded sandstone-mudstone had poor reservoir quality due to its poor sorting and low permeability. The researchers concluded that the shoreface environment provided better reservoir quality compared to the upper offshore environment.