Research On Inversion Of Scaling Thickness And Optimal Utilization Of Energy In Multi-source Branched Water Injection Network

Water injection is an important way to improve oil recovery and is also the most mature technology.With the oil field entering the high water cut period,the water injection volume is increasing and the scale-forming substances are more and more,which makes the scaling problem of water injection pipeline more and more serious.Pipeline scaling will reduce the flow area,resulting in increased energy consumption in operation.At present,the power consumption of water injection system in high water cut oilfield has accounted for more than40% of the total power consumption,and it increases with the increase of injection volume.In addition,pipeline scaling will also affect the life of the pipeline and the cost of operation and maintenance.Because it is buried pipeline,the scale thickness of water injection pipeline is difficult to measure,and the scale removal plan is generally made according to experience,which leads to high cost of scale removal and poor effect.If the scale thickness of the pipeline can be retrieved according to the production operation data,it will be helpful to formulate a reasonable scale removal plan for the pipeline,reduce the cost of scale removal,and at the same time help to formulate an optimal energy utilization plan for the water injection system and reduce the energy consumption of water injection.In this paper,the scale thickness inversion method and the optimal energy utilization of water injection pipe network are studied for the water injection system of multi-source dendritic oilfield.The main results are as follows:According to the process flow and pipe network structure characteristics of multi-source dendritic oil field water injection system,combined with binary tree algorithm and hydrodynamics theory,the corresponding hydraulic simulation calculation method is established.On this basis,the scale thickness inversion model of a single pipe and the scale thickness inversion model of the whole water injection pipe network are established based on the actual production operation data.According to the structural characteristics of the inversion model,a hybrid particle swarm optimization algorithm(PSO)is proposed by combining the penalty function method with PSO.According to the principle of energy balance,the energy analysis model of multi-source branched oilfield water injection system is established,and the corresponding energy consumption evaluation index is established.With the minimum energy consumption of water injection as the objective,the optimization mathematical model of water injection pump operation scheme of oilfield water injection system is established.The scale deposition thickness inversion,energy consumption analysis and evaluation of Shen2 Lian and Shen4 Lian water injection systems are carried out.The scale thickness inversion results show that the scale thickness of the main pipeline is generally greater than 10 mm,and the scale thickness of the branch pipeline is generally greater than 4mm,and the scale phenomenon is serious.The results of energy consumption analysis show that the two links with the largest energy loss are the loss of water injection pump unit and the loss of wellhead throttling.The energy loss of these two links accounts for more than 60% of total energy loss.According to the results of energy consumption analysis,the optimal transformation scheme of energy utilization of the system was formulated,which mainly included the targeted descaling of water injection pipe network,the replacement of motor of 3# water injection pump unit of Shen quadriple and the addition of frequency conversion device,the replacement of motor of 3# horizontal pump unit of Shen quadriple and the transformation of technological process of injection well,etc.After the transformation,the annual electricity saving is 1.0642 million yuan,and the energy saving effect is good.