Comparative Evaluation And Applicability Analysis Of Different Types Of Mechanical Screen

At present,sand production has become one of the main problems troubling the development of loose sandstone reservoirs.For sand production,sand control is the main solution,and mechanical sand control screen is widely used in oil and gas wells.There have been many kinds of mechanical screens for different and retaining mediums and structures,which have different adaptability for different reservoir characteristics.In order to select suitable screen for various complex well conditions and achieve the best sand control effect,it is necessary to study the influence law of different factors on the performance of different types of screen,and conduct the performance comparison and applicability evaluation of different screens,so as to provide direct support for the screen selection.Domestic and foreign studies have been carried out many optimization and performance evaluation methods of screens,but there are still problems of incomplete factors and poor versatility.In addition,there are few studies on the influence of formation sand uniformity coefficient and shale content on screen sand retaining performance.In view of the above problems,this paper based on sand control theories and laboratory experiments,comparing the different types of screens firstly;Then summing up the key factors affecting the blockage of mechanical screen,through experiments to study the influence of different factors;According to the statistical results of a large number of laboratory experiments,different types of screen tubes were determined under the condition of clear water and viscosityincreasing water of 5m Pa·s.For the application range of formation sand uniformity coefficient(1.5-15)and shale content(0%-30%),an evaluation chart of the suitability of selected screen tubes based on the characteristics of formation sand was drawn to provide a basis for the optimization of practical application of different types of screen tubes in the field.The results show that displacement time,fluid viscosity,flow rate,formation sand uniformity coefficient and shale content are the key factors affecting the plugging of sand retaining medium.Among them,the uniformity coefficient and the shale content have a synergistic effect on the blockage of sand retaining medium.The greater the uniformity coefficient is,the worse the sand retaining performance of the screen will be.On the premise that the screen can effectively retain sand,the argillaceous material will aggravate the phenomenon of blockage,reduce its liquidity and improve the performance of the screen.The experimental results show that when the formation sand uniformity coefficient is 1.5,the permeability decreases by more than 90% after the sand blocking equilibrium.When the uniformity coefficient is 15,the permeability decreases by only 10%-20% after the network media and metal wool media are balanced,and the permeability of gap media still drops by more than 80%,indicating that different types of sand retaining media have different sensitivity to the clogging of formation sand uniformity coefficient.The results of mechanical screen sand retaining performance evaluation show that the gap type screen has good applicability in the range of uniformity coefficient 8-15 and shale content 0%-30%.The screen type screen has good applicability in the range of uniformity coefficient 1-8 and shale content 0%-30%.According to the comprehensive analysis of experimental results,four sets of suitability evaluation charts of different types of screen pipes and sand retaining media based on uniformity coefficient and shale content were presented.