Heat Transfer Analysis On Steam Injection Loop Pipe Network Of Oilfiled

At present, the steam injection heavy oil thermodynamic recovery type of Liaohe Oilfield is one boiler with one injection, this steam injection type is suitable to the oil wells which are disposed dispersedly, it is convenient for management and maintenance, but for the oilfield block in which the steam injection wells form a scalization, centralization and stabilization, this steam injection type has irreconcilable disadvantage, for example:the low efficiency caused by light load of boiler, the high cost of maintenance and management caused by the great quantity of boiler rooms. To solve this problem, a study on the applicability of ringlike steam injection pipeline net is significant to reduce the quantity of boilers and increase the load of boiler. To study new steam injection pipeline allocation, the suitable thermodynamic and hydraulic computing model must be defined, but there is no thermodynamic and hydraulic computing model applied in ringlike steam injection pipeline net nowadays. As an integrant part of pipeline net, the thermodynamic and hydraulic computing model of ground steam pipeline has a position of equal importance, but most models detach hydraulic and thermodynamic calculation from each other, do not consider the coupling effect between water power and heating power, so studying the energy loss model of ground steam pipeline which considers that coupling effect plays an important role to perfect thermodynamic and hydraulic computing model of steam injection pipeline.On the basis of literature consulting, site investigation and the existing studies, the flow and heat transfer state of steam in the pipe is analyzed and the energy loss problem of steam injection ground pipeline is researched in this paper. The hydraulic and thermal calculation model of steam injection ground pipeline is established, the calculation program is developed and the influences on pipeline heat dissipation is calculated and analyzed according to heat transfer, engineering thermodynamics, fluid mechanics etc.. Hydraulic and thermal calculation of pepeline is associated and restricted by hydraulic and thermal calculation model, the average density of steam and specific heat at constant pressure. And by means of graph-theory, the hydraulic and thermal calculation model of loop steam injection pipe network. Taking the steam injected of wellhead, dryness of steam, steam injection pressure etc. as constraint conditions, the sum of reduced cost of pressure drop and the reduced cost of investment and heat loss of steel pipe and insulation material as objective function, the parameter (diameter, thickness of insulating layer) optimization mathematical model of loop steam injection pipe network is established. Because the optimization mathematical model is a NP-hard, optimal objective function can not be directly solved. Compared with various optimization algorithm, the genetic algorithm is finally adopted to solve problem and the MATLAB is used to slove the optimal calculation program. In this paper, analysis of examples is given, the combination of diameter and insulating layer thickness that the cost of pipe network is lowest is obtained.Considering the coupling effect between hydraulic and thermal of ground steam pipeline, the new energy loss model of ground steam pipeline is given and carried out by experiments. On this basis, the hydraulic and thermal calculation and optimization model of loop steam injection pipe network is established and the analysis of examples is given. The research results in this paper provides reference function for the future design and transformation of heavy oil recovery steam injection pipe network.