Erosion Simulation Analysis And Life Prediction On Slotted Screen

In the process of oilfield development,whether sand control design is reasonable is very important for normal production of oil wells.If the sand control fails,it may cause the wellbore plugged and even may cause the well scrapped.The slotted screen is the most common sand control tool in mechanical sand control.In the current sand control design process,the selection of screening pipe parameters in the initial stage of sand control is mainly considered,but the influence of the screen erosion on the long-term sand control is rarely involved.Erosion is one of the main causes of slotted screen failure,and it is also the key factor to affect the life of sieve pipe.There are few researches on the erosion of slotted screens at home and abroad so far.This paper studies the erosion of slotted screens by numerical simulation on basis of the physical properties and production conditions in the field,and establishes the prediction model of the life of slotted screen This paper mainly solves these problems:(1)how to ensure the accuracy of the erosion simulation data;(2)how to determine the corresponding relationship between the slotted screen sand control life and the simulated data;(3)how to establish the life prediction model of the slotted screen.In view of the above problems,the following aspects have been completed:(1)On the basis of the existing erosion simulation experiments,the erosion simulation calculation of slotted screen is carried out by using the similar model,then the simulated data and the existing experimental data are compared in the same condition to verify the reliability and accuracy of the erosion model.(2)The four factors affecting the erosion of the slotted screen are analyzed by orthogonal test.Then the primary and secondary sequence which affects the erosion factors on the erosion of the slotted screen is obtained,and the range of the maximum erosion rate is determined.At the same time,by using the principle of single factor analysis,the erosion area is defined,and the location which the maximum erosion rate appears is determined,and the influence law of the four factors on the slotting erosion is obtained.(3)The maximum erosion rate obtained from orthogonal analysis and single factor analysis is used as the data basis for the establishment of the life prediction model,and the formula for the erosion width in per unit time and the maximum erosion rate is deduced.Using the failure criterion of the slotted screen erosion establishes the calculation model of service life.(4)Based on BP neural network structure,activation function and training parameters,the mapping relationship between production pressure difference,dynamic viscosity,particle size level,sand content level with slotted screen sand control life of the slotted screen is established,namely life prediction model.The error of the model is analyzed.In this paper,the influence of four factors on the erosion of the slotted screen is studied and the qualitative analysis is carried out,and the reference value is provided for the study of the erosion mechanism of the slotted screen.The prediction results of service life of the slotted screen under actual working conditions by using the life prediction model have certain reference significance for the design and implementation of sand control in the actual work over operation.