Research On Oil-water Separation Of Acid Fracturing Fluid

Acid fracturing process as the main measure of oil yield,the latest treatment process will produces a large fracturing fluid recovery,which has the characteristics of high viscosity,high acidity,high stability and high COD,it is difficult to separate oil and water.In this study,acidification fracturing fluid treatment and oil-water separation are investigated based on previous studies,treat acid fracturing from Tianjin Dagang oilfield with hydrocyclone technology and chemical dehydration technology,the experimental study of chemical viscosity reduction,hydrocyclone oil removal and chemical dehydration were carried out.Acid fracturing fluid gel breaking experiments are performed using the chemical oxidation method,the experiments of gel breaking shows that the optimum condition are that,the concentration of FeSO₄ is 0.02%,the concentration of H₂O₂ is 0.03%,the pH is 5,the reaction time is 25min,the reaction temperature is 45,the highest reaction efficiency is more than 81%.The demulsification of acid fracturing fluid using RH-3060 and static experiment required RH-3060 concentration is 500 ppm,dynamic experiment for 150 ppm;the use of LE-26 of crude oil dehydration,the concentration of LE-26 is 200ppm,dehydration rate of overall compatibility with RH-3060 can reach 84%.According to the experiments of structural parameters,the operating parameters and physical parameters of the hydrocyclone are carried out.The experiments of hydrocyclone tests show that the optimum structure parameters for 3 cone sections,guide vane angle of15°,6mm overflow diameter and 930mm tail pipe length;operating parameters for the3.5-4.5m3/h,overflow rate is choosed according to the specific content,the overflow rate is10%in this study.The fracturing fluid is broken after 48h,the viscosity is 3.2mPa·s,the separation efficiency can reach above 80%.When the viscosity is 10.1mPa·s,overflow port diameter is 8mm,the volume of 0.75 m³/h,the separation efficiency can reach 82%.Under the optimal structure parameters and operation parameters,gel breaking 48h,using two-stage hydrocyclone series processing site fracturing fluid,the highest efficiency is 98%and underflow oil below 1500 ppm.The separation efficiency prediction model is built base on the above experiments.Based on the above experiments,a set of acid fracturing fluid treatment technology is designed,and the accuracy of the aquifer model is verified.