Sandy braided-river deposits with high net-to-gross sand ratios are commonly attractive reservoirs, yet internal lithologic heterogeneities, particularly the presence of low-permeability mudstone deposits, significantly complicate the development of such units. Previous work has focused on measuring the scale and distribution of mudstone deposits in outcrop analogs; however, because of extreme differences in scale, discharge, sediment load, and geologic history, the results of these studies are difficult to apply with confidence to a wide range of sandy braided-river reservoirs. Based on work in modern braided rivers (Niobrara and North Loup rivers, Nebraska) and ancient braided-river deposits (Kayenta Formation,...