The study looked at how sand deposits formed in a lake-like area, specifically in the Es_3 layer of a region called Bonan oilfield in China. By using geological and geophysical methods, researchers figured out the types of sand formations in this area: outer turbidite fans and fluxoturbidites. They found that these formations were created in a small sag near the source area. This helps us understand how sediment moves in this type of environment and how it accumulates to form sand bodies.