Study On The Performance Of Water Injection Wells In Unconsolidated Sandstone Reservoir

Water flooding is also called “secondary oil recovery”,which is achieving oil by providing energy for the formation in the case of formation energy failure.Because of the weak cementation and the clay minerals in loose sandstone reservoir,formation around injection wells is susceptible to particle migration blockage,water sensitivity,and formation sand production,resulting in formation pollution and permeability decrease,which reduces water injection efficiency and negatively influences the oil production.By studying the dynamic production of injection wells in loose sandstone formation,the rule of formation pollution in the process of water injection can be obtained,and the advice for optimization of water injection operation and plug removal operation can be provided,so as to improve oil recovery.This paper analyses the dynamic production of injection wells in unconsolidated sandstone formation,which locates in Bohai region,and the rule of formation pollution around the injection wells is obtained.According to the given injection pressure and injection volume,the injection performance curves can be obtained,and the corresponding water injection indexes are determined,so that the production status of injection wells in different time can be inferred.According to the dynamic analysis results of injection wells,the permeability and radius of damaged zone in different time can be obtained,which provides the basis for the adjustment of water injection scheme.The studying results of this paper possess significant application prospect,the rule of formation pollution around injection wells can be obtained through dynamic analysis,so as to accurately predict water flooding efficiency,and provide the basis for the adjustment of water injection scheme.By analyzing the permeability and radius of damaged zone around the injection wells in different time,the pollution level and range at every moment can be obtained,so as to clarify the rule of formation pollution in loose sandstone reservoir during water flooding,and lay the ground for the plug removal operation.Method to dynamically analyze the pollution of injection wells is provided,which provides accurate guidance for the establishment of development plan.