RESULTS OF RESEARCH OF CHEMICAL METHODS TO IMPROVE THE EFFICIENCY OF WATERTREATMENT FOR INJECTION INTO THE SYSTEM OF RESERVOIR PRESSURE MAINTENANCE

Abstract

The separated water from Preliminary Water Removal Unit isused as a working agent of the pressure maintenance system and, accordingly,the quality must meet regulatory requirements. Pumping waterinto the reservoir without preliminary preparation and considering thephysicochemical properties of water and porosity of the reservoir leadsto contamination of the bottom-hole zone of the well and to reducing theintake capacity of injection wells. Recovery of injection well performancerequires a lot of material and energy costs.The use of gravity sedimentation and oil sedimentation tanks make itpossible to obtain water with a content of petroleum products up to30-50 mg/l and mechanical impurities of 20–40 mg/l. The standardapproach to solving the problems of increasing loads and destruction ofstable oil-water emulsions is increasing the capacity of the treatmentfacility by building additional reservoir equipment. This approachinvolves a number of significant time and financial costs and does notallow to organize a solution to the problem in a short time.The influence of deoilers to the quality of water treatment has been studiedin order to provide deeper purification of reservoir water for thepossibility of obtaining water containing petroleum products andmechanical impurities up to the requirements of the OST-39-225-88.Deoilers do not dissolve or remove petroleum products. Deoilers enlargepetroleum productsby bringing them closer to each other. Then mechanicalimpurities and petroleum products must be removed from the existingwater treatment system. The research of the influence of deoilers forthe stabilization of the oil-water emulsion has been carried out.According to the results of studies of the effect of deoilers on the qualityof water treatment, with the use of all tested deoilers, the content ofpetroleum products in the water decreases and it is possible to obtainwater of the quality required by OST-39-225 under the conditions of oiland water treatment during the technological mode of operation of theUPS. At the same time, however, the supply of trapped oil to the pipelinein front of the oil sedimentation tanks leads to an increase in the residualwater in the treated oil. To minimize the risks of disruption of thetechnological regime at the UPS, the recommended ratio of incomingliquid — captured oil when using deoilers for water purification wasdetermined.