Study On Optimization Method Of Water Injection Quality In Block M Of Dawangzhuang Oilfield

Oilfield water injection development is a more effective development method currently adopted at home and abroad.In the process of water injection development,as the amount of water injection increases,the cost of water treatment also increases,resulting in an increasing proportion of water treatment costs.Especially for low-permeability reservoirs,water injection is difficult and water treatment costs are high,and the contradiction between cost and economic benefits is increasing.In this paper,the M block is taken as the research object,and the water quality index is regulated to meet the problem of poor water quality compatibility in the reservoir to achieve cost-effective development.The main work carried out in this paper is as follows:Firstly,analyze the characteristics of the reservoir,clarify the mainstream throat radius and reservoir damage factors,prepare for the regulation of water quality indicators,and analyze the current water injection conditions to find the problems of water injection.Secondly,The theory of reservoir damage was studied.The laboratory experiments were carried out.The suspended solids injury experiment,emulsified oil injury experiment,injected water corrosion injury experiment and bacterial index control experiment were carried out.The compatibility high and low limit design was carried out,and the preliminary determination was made.Water quality indicator control plan for M block.Thirdly,The theory of water quality loss caused by water quality was systematically studied,and a water absorption capacity model was proposed.A set of procedures was developed,which can be applied to predict the water absorption capacity under the condition of the coexistence of suspended solids and emulsified oil.Through the example analysis,the results predicted by the water absorption capacity model can well reflect the change trend of the water absorption capacity of the M block water injection well,which has a good agreement degree and high reliability.Fourthly,based on the technical and economic evaluation,the water quality index was adjusted by the water absorption capacity model,and six sets of water quality index schemes were designed.The water treatment cost and the injection cost were compared,and the most economical and reasonable water quality water quality index scheme was selected.Finally,through the regulation research on the water quality of M block,the water injection problem of such low-permeability reservoirs in Dawangzhuang Oilfield is solved,which has a guiding role for similar oil reservoirs.