The reservoir configuration of deepwater turbidite sandstone oilfields is complex, and the development conflicts are prominent. Studying the rules of water cut increase in oilfields can help identify the problems faced by oilfields at different stages, fully explore the internal potential of oilfields, and lay the foundation for subsequent optimization and adjustment of water injection and production. By using the actual production dynamic data of the oilfield, and utilizing the analysis of the distribution characteristics of the reservoir and the relationship between injection and production connectivity, as well as considering the water cut increase pattern after water breakthrough, the relationship between injection and production connectivity is divided into three types, and the water cut increase pattern of oil producers is divided into four types. The mechanism of water cut increase of oil producers is mainly controlled by the connectivity of the reservoir: for oil producers with single-period channel directly connected to water injectors with lobe, the reservoir development and internal connectivity are good, so the injection-production efficiency is rather good, resulting in a “convex rapid increase” water cut curve; for oil producers with multi-period sand bodies in staggered connection, the internal connectivity is good, but the physical properties and connectivity of the overlapping parts are poor, the water injection effect is slower, and the water cut increase curve shows a “convex relatively fast increase”; for oil producers with multi-period sand bodies in staggered connection and affected by fault barriers, the physical properties and connectivity of the reservoir are poorer, the water injection effect is much slower, and the water cut increase curve shows a “linear increase”; some oil producers are affected by the different water breakthrough time of different layers, and the water cut increase curve shows a “stepped increase”. Finally, based on a new water cut prediction model, a benchmark of four types of normalized model parameters is established to guide the subsequent water cut increase prediction of other oil producers.