Gas Injection Optimization Technology Study For Gas Lift System In Zhanazhol Oilfield

High pressure gas is injected into the wellbore from surface and mixed with the produced liquid within wellbore.Depend on the expansion of injected high pressure gas,the density of the mixed fluid reduced and the fluid is lifted to the surface.The main systems including compressor stations,ground gas distribution station,single well production system,and the ground production system.The liquid production range of gas lift is rather wide,with a deep lifting depth.Also,there is no mechanical wearparts.So the operation and management is easy.And gas lift is one of the world's most widely used artificial lifting method.In the process of gas lift production,one of the key factors which always restricts the amount of liquid producing is gas supply.Especially when the scale of gas lift expanded,as a result of the big investment and long term construction for surface gas supply system,the contradiction between supply and demand is mostly remarkable.The scale of gas lift in Zananorl Oilfield in Kazakhstan has been expanded in recent years,and the water cut rising greatly.The contradiction between maintain of single well productivity and gas supply and the expansion of gas lift scale becoming more and more conspicuous.Therefore,how to reduce the injected gas liquid ratio and enhance sysetm efficiency of gas lift to achieve the stable production of the oilfield has become a urgent issue.In order to ensure the smooth operation of the massive gas lift production,we should consider the whole gas lift system as one unit to do optimization and improve the gas lift efficiency.Via the optimization of whole system,realize the improve of system lifting efficiency and save the injected gas.Gas lift system optimization is usually conducted under the condition of limited gas volume provided to meet the need of wells' largest gas injection;The lack of gas injection will certainly limite the production of oilfields,but if the gas can be assigned to each single well according to different proporations,the total oil production of system is often different.the object of system optimization is to study and get the suitable ratio of gas injection volume to each well,so that to maximize the system production.By using the characteristic curve of each single well,which is corresponding to the well production and injection volume curve.based on the characteristic curve of wells,we can accurately determine the capacity of a single well,so the characteristic curve is the theoretical basis of system optimization.The producing state of gas lift wells changes in the development of oilfields.Usually a gas supply system changes at the relatively stable circumstances.While the parameters of pressure and fluid features of gas lift wells are dynamic at the entire production cycles.By using the system optimization in the gas lift oilfields,that is put the factors such as the gas source,compressors,pipelines,wellheads,the well column,well' s capabilities of flow into a integral consideration and optimization.Through gas volume controlling,to make the gas lift production adapt the change of the entire oilfield.Bringing the good efficiency of entire production system.the use of system optimization techniques will have a big different result compared with single well optimization.The greater of the production scale,the more of difference.The system optimization can maximize the efficiency of the gas lift and enhance the level of development of the entire oil region...