一种无固相高密度封隔液的开发与性能评价

Development and performance evaluation of a solid-free high-density sealing fluid

针对高温高压井开发需要高密度的封隔液来平衡地层压力和油套管间的压差问题,采用原料易得、溶解性好的焦磷酸钾和磷酸氢二钾复配的无机盐作为加重剂,缓蚀剂、除氧剂作为辅剂,制备了无固相高密度封隔液TS-12,并对其进行耐温、结晶、流变以及耐腐蚀性能评价。结果表明,封隔液TS-12耐温可达180℃、结晶温度为-19℃,且封隔液为缓冲体系,可抵抗酸性气体CO_(2)干扰;封隔液TS-12为牛顿流体,高密度条件下流动性好,易于泵注;封隔液TS-12对不同类型的井筒钢材的腐蚀率都小于0.076mm/a,具有较好的应用前景。

In response to the need for high-density sealing fluid in the development of high-temperature and high-pressure wells to balance formation pressure and pressure difference between oil and casing,an inorganic salt composed of potassium pyrophosphate and potassium dihydrogen phosphate,which were easy to be obtained and have good solubility,was used as a weighting agent.Corrosion inhibitors and deoxidizers were added as auxiliary agents to form a solid-free high-density sealing fluid TS-12,with a maximum density of 1.8g/cm~3.The temperature resistance,crystallization performance,rheological performance,and corrosion performance of the sealing fluid TS-12 were evaluated.The results showed that the sealing fluid TS-12 had a temperature resistance of 180℃and a crystallization temperature of-19℃.The sealing fluid was a buffer system that can resist the interference of acidic gas CO_2.The rheological properties indicated that the sealing fluid was a Newtonian fluid with good flowability under high-density conditions and easy to pump.The corrosion rate of sealing fluid TS-12 on different types of wellbore steel meets industry standards and has broad application prospects.