Experimental Study Of Physical Modeling On Water Flooding Regulation In Tahe S80 Fractured-vuggy Carbonate Reservoir

With the growing proportion of fractured-vuggy carbonate reservoirs,the development of fractured-vuggy carbonate reservoirs plays a very important role in the replacement of energy resources in China.However,due to the complex types of fractured-vuggy reservoirs.random distribution of cavities and strong heterogeneity,the development of such reservoir is difficult and the recovery is low.Tahe Oilfield is the largest fractured-vuggy carbonate reservoir in China.water flooding is an effective way to develop it,but the effect in part of well groups become worse or failure.Therefore it is a problem to be solved to recognize the water flooding process,which can further develop such reservoirs more effectively.For the research of fractured-vuggy carbonate reservoirs,physical modeling experiment is a more effective method.Based on the investigation and summarization of a large number of documents,combined with the geology and development data of Tahe S80 block,the typical fractured-vuggy models were designed and manufactured.The experimental study of the water flooding regulation is carried out with the single and combined models.The main achievements of this paper are as follows:(1)Based on the summarization and analysis of geology,development and flow characteristics in fractured-vuggy carbonate reservoirs,according the geological data of Tahe S80 block,we designed and extracted three types of fractured-vuggy experimental models,including four large cavities,three fracture-vugs and three fracture-caverns.(2)Using the single fractured-vuggy experimental model to research the basic water flooding regulation of-injection and production position,influence of injection rate,injection production ratio and water injection mode.The results showed the best injection location for fractured-vuggy reservoirs is low position injection high position production,except for large vertical caves;Optimal injection rate is between 5ml/min and 20ml/min;Injection production ratio can inot be studied by using these fractured-vuggy experimental models;The time of water injection is shorter and the production well is closed for a long time,which is more applicable to large cavities and fracture-caverns,and the time of water in.jection is equal to the closing time has higher recovery in fracture-vugs models.(3)According to the water injection mode of the actual water injection well,the physical modeling experiment on water flooding experiment of the combined fractured-vuggy model is carried out.Through the analysis and selecting of the main f’actors in water flooding development.the adjustment experiment of water flooding is carried out after the experirment of combined fractured-vuggy model.The adjustment experiment of fractured-vuggy reservoir water flooding results showed that when the development of fractured-vuggy reservoir is to the late stage,using the original injection and production well groups can improve the oil recovery very little or no longer produce oil,but drilling more injection wells or oil wells is a good way to enhance oil recovery.