大通径桥塞压裂用可溶解球研制及性能评价

Development and Performance Evaluation of Dissolvable Balls for Large Borehole Bridge Plug Fracturing

为解决国内可溶解憋压球无法满足大通径桥塞压裂要求的问题,采用网络结构设计了以镁铝合金为基体并添加Zn、Cu等材料而形成的多元材料,以抗压强度、屈服强度、溶解速率为目标优化了材料中Zn、Cu的加量,研制了与大通径桥塞压裂配套用的大直径、高强度、可溶解合金材料及憋压球。经测试合金材料的抗压强度与屈服强度分别超过了430和330 MPa,直径89.027mm憋压球承压超过70 MPa,且喷涂防护膜后球体稳定承压达到6h;93℃条件下在3%KCl溶液中球体溶解90%体积所需时间约为92h;在胍胶压裂液中的溶解速率虽然比在1%KCl溶液慢,但200h也能溶解球体90%的体积。这表明,大直径可溶解憋压球能满足大通径桥塞压裂所需的高强度、快速溶解的性能要求。

In China,conventional dissolvable balls are not adaptable to large borehole bridge plug fracturing.To solve this problem,a large diameter and high strength dissolvable ball was developed.It is a multi-component system with magnesium alloy as matrix as well as Zn,Cu and other elements in a net structure.The Zn and Cu content was optimized to improve the system＇s compressive strength,yield strength and dissolution rate.Some tests showed that the compressive strength and yield strength of the system were over 430 MPa and 330 MPa,respectively.Pressure resistence capacity was over 70 MPa for the 89.027 mm diameter dissolvable ball made with the system.After coating the ball,pressures were stable for 6hours,and 90% of the ball dissolved in a 3% KCl solution at 93℃in about 92 hours.In gel,the ball would dissolve more slowly than in 1% KCl solution,and 90% of the ball was dissolved within 200 hours.We have concluded that the large diameter dissolvable ball can meet the requirement of high strength and rapid dissolution in large borehole bridge plug fracturing.