Study On Mechanism And Characteristic Recognition Of Water Channeling In Heavy Oil Reservoirs With Bottom Water

Steam huff and puff is an effective way to exploit heavy oil reservoirs.However,the existence of bottom water can lead to water channeling and low reservoir recovery.Therefore,it is important to study the characteristics of water channeling of bottom water,to analyze the influence factors of the range of water channeling and the intensity of water channeling,and to optimize the treatment of water channeling to improve the development effect.According to the physical property and relative permeability of the reservoir fluid,a numerical model is set up to analyze the variation of water cut and the ratio in the way of linear flooding,spot flooding and multi point water flooding,which can be used to identify the water channeling model in the field.Through single factor analysis and orthogonal numerical experiments,the influencing factors of water channeling area and water intensity were analyzed.Based on the characteristics of steam huff and puff and the seepage law of bottom water,a coupled mathematical model is established to predict the breakthrough time in the development process,and the sensitivity analysis is carried out.Finally,a geological model and numerical model are established to optimize the parameters of nitrogen injection and nitrogen foam injection,so as to provide guidance for on-site water channeling control.The results of numerical model study show that,unlike the regular reservoir water channeling principle,the water cut shows a slow increasing trend in the steady production period of each cycle of puff and puff at point like water channeling.The water cut increases to a higher level in a short time and keeps stable at linear water channeling.The water cut increases at a greater speed and gradually decreases at a higher rate of water.the heterogeneity and the height of water repellent to the bottom water has a great influence on water cahnneling area.And among geological factors,the longitudinal permeability and the water body size affect the intensity of the water channeling greatly.The biggest influence of injection production parameters on bottom water channeling intensity are steam injection intensity and drainage volume.The prediction results of mathematical model are in good agreement with field data,which can be used to predict the water breakthrough time of horizontal wells quickly.According to the optimized scheme,the periodic oil production of water flooded well can be greatly enhanced.