Injection And Production Allocation Optimization Study On High Water Cut Reservior

Since the most of the developed oil field on land reach high water cut stage,the relationship of oil and water as well as the distribution of reserve oil will be more and more complicated,the formation heterogeneity being more distinct as the development going on.The imbalance of oil reserved and produced,the difficulty of maintaining oil production stable and low economic benefits make raising recoverable reserves,producing stably in a high speed and putting more reserves to use to be the urgent mission for a high water cut oil field.Faced with the challenge of low oil price,making full use of water injected to further improve oil recovery by reasonable injection and production allocation is the path to stabilizing the production for high water cut oil reserves.Sectors inside a well group is partitioned,and the field data after numerical simulation computation can be collected in a quantitative way and the production situation is characterized.Coefficient of variation of injection rate,permeability and well distance increase leading to the rise of inhomogeneity of well group development and residual oil saturation,resulting in decrease of oil recovery.As the single strorage coefiecient variation between well groups and the oil saturation variation in well group descreases,the oil recovery factor of the well group increases.Based on the transformation of dynamic streamlines between injectors and producers,a method to analyze the injected water flow direction in stratum.And the effectiveness of injection and production allocation is evaluated by the error between water allocated and the actual flow.Areas with high permeability,high bottom hole pressure deviation and areas having been acidized and fractured can obtain more injected water.At the same time,the existence of surrounding well groups can affect the allocation of injected water,decreasing the allocation of nearby area.Formation coefficient,pore volume,residual oil saturation,residual oil reserves and pressure are picked to determine the main control factor of injection and production allocation.A method accurate to sinle layer and single direction to allocate the injection and production volume is proposed.When taking the complicated influence of multi layer and multi well groups,a multi well group cooperative optimization method is put forward.While allocating the production,KH and residual oil reserves are the main factor and the the weight ratio is 4:6,varing as the water cut changes.Injection is allocated based on pore volume and corrected by oil saturation.When the injection and production is cooperatively optimized,the objective function is single storage coefficient variation and oil saturation variation.The method is applied on actual sector of Shengli oil field,proved to be effectively improve the high water cut reservoir development effect.