Study On Optimization Of Intermittent Pumping Working System In Low Permeability Reservoir

Low permeability reservoirs have become the main resource base for increasing reserves in China.The development of low permeability reservoir has become an important strategic basis for ensuring the sustainable development of China's oil industry.The Low permeability reservoir is poor in physical properties.Single well production is very low and difficult to product.When the pumping wells in the implementation of continuous production,due to lack of formation liquid,dry pumping phenomenon is widespread.Followed by reduced pump efficiency,increased mechanical wear,pump failure rate is high,while causing electricity waste.Intermittent pumping is an economically viable means for such oil wells.The use of this technology can ensure that the cycle of high liquid production conditions,the maximum reduction in electricity costs,improve the development of low permeability reservoirs economic benefits.In this paper,with the characteristics of low permeability,low production wells,Combined with the inflow performance relationship of low permeability reservoirs,variation law of working fluid level and pump efficiency analysis,based on the relationship between formation capacity and pumping capacity,established a coupling model of a stratigraphic inflow and wellbore outflow.Through the study of the reasonable intermittent pumping working system,the optimal intermittent pumping time,optimal intermittent pumping period,the range of working fluid level and reasonable allocation of switch well time are determined.The optimal working system can provide theoretical guidance for the practical application of intermittent pumping technology in low permeability reservoirs,and finally achieve the purpose of improving the economic benefits of low production wells.The study shows that the inflow of low permeability reservoirs into the dynamic model,considering the stress sensitivity,supply radius,crude oil viscosity and threshold pressure gradient,can truly reflect the law of low permeability reservoir effluent seepage.The actual production value is 1.14% less than the calculated value of the model,and the calculation accuracy is higher.The outflow dynamics of the wellbore are based on the law of pump submergence depth and pump efficiency,and the mathematical expression is fitted by empirical method.Coupling parameters of flowing sandface pressure and pump efficiency change dynamic in real time.The intermittent pumping coupling model is established in turn to carry out the three parameters of reservoir parameters,process parameters and economic parameters optimization to complete the optimization of the intermittent pumping working system of target block.Example application compared with continuous pumping,the cycle of liquid production is increased by 2.8%.Single well power consumption reduced by 70%.Single well increases oil profit by 7558 RMB per month.Electricity saves at least 3326 RMB per month.The optimal intermittent mining system is economical,efficient and feasible.