Abstract: The offshore fluvial sandstone are characterized by large individual sand body thickness, quick reservoir lateral change. In addition, the oil gas and water layers are interbedded in vertical, and the reservoirs are poor in connectivity in plane. In the light of these characteristics, through ten years of continuous exploration and development practice, a series of reservoir quantitative descrip-tion technologies have been developed and improved by Bohai Oil Field. These technologies can describe the sand body distribution. In offshore oil field, the exploratory well spacing is large, and well control degree is low, with little coring data. In this case, how to understand the horizontal distribution of reservoir is very difficulty. The reservoir description technology can solve this problem. Based on the well drilling data, reservoir description technology can find potential sand body. As more and more fluvial oilfield is developed in Bohai Oil Field, the reliability of reservoir description technique has been confirmed. A large mounts of examples show that reservoir description technique is effective technical means of prediction and description of reservoir in Neogene fluvial sand, Bohai bay. This technique can also be used to evaluate the similar geological background of fluvial reservoir for reference.