Evaluation On Physicochemical Properties Of Sand Control Screen For High Temperature And Pressure Gas Reservoirs

In the mining of high temperature and high pressure gas fields at sea,due to the special nature of high temperature and high pressure,a series of problems,such as erosion and corrosion of mechanical sand control screens will happen,how to evaluate and optimize the comprehensive performance of mechanical screens under high temperature and high pressure is especially important.At present,most of the screen corrosion tests are aim at metal materials under normal temperature and pressure.The evaluation method is mainly weight loss,and the corrosion speed prediction model is mostly empirical prediction model.Screen erosion experiments are mostly single-point erosion,it is difficult to simulate the in-situ non-uniform inflow,and only the erosion damage time is used for performance evaluation,the systemized screen evaluation and preferred method are not formed.Based on the above problems,this paper designs an anti-erosion performance evaluation device for horizontal wells in gas reservoirs.Combined with experimental equipment test data,this paper proposes an evaluation method for erosion resistance of screen characteristics,and studies the erosion prediction model.At the same time,a new dynamic corrosion test device for screens was developed.39 sets of screen corrosion tests were carried out.With the new screen corrosion resistance evaluation method,the screen corrosion rate was calculated to correct the existing model;finally,the life prediction and case analysis of the mechanical screen are carried out in combination with corrosion and erosion evaluation.The results show that the factors affecting the erosion of the gas well screen include flow velocity,erosion distance,sand content,erosion angle and sand particle size.The new horizontal well mechanical screen erosion resistance evaluation device can test the anti-erosion performance of screen under different influencing factors.The corrosion of the screen in the gas field is affected by many factors,such as temperature,CO₂ partial pressure,CO₂ content,water-gas ratio and so on.With the increase of CO₂ partial pressure,the average corrosion rate of screen increases.When the partial pressure of CO₂ is 0-5 MPa,the corrosion rate increases slowly.When the partial pressure of CO₂ is>5 MPa,the corrosion rate increases rapidly with partial pressure.When the partial pressure of CO₂ is 14.5 MPa,the corrosion rate of the screen is almost ten times that of the CO₂ partial pressure of 1.5 MPa.The corrosion morphology of the screen is very different under the different experimental time.Corrosion is more serious with time;as the temperature increases,the average corrosion rate of each part increases first and then decreases.When the temperature is 140°C,the corrosion rate of each part reaches the maximum.When the temperature rises to 190°C,the corrosion rate decreases.As the water-gas ratio increases,the average corrosion rate of each part increases gradually.After the experiment,the corrosion of the base tube is serious and the rust is obvious;the outer protective cover is relatively slightly corroded,and the surface of the sample loses the metallic luster;the surface of the substrate before and after the corrosion of the sand-shielding medium 316L stainless steel has no obvious change;when the three components of the screen are formed as a whole,The interaction between the interactions makes the corrosion situation more serious.At the same time,this paper studies the corrosion rate calculation model of different parts of the screen based on the experimental conditions,and provides some theoretical basis for predicting the damage life of screens under different conditions.