深水完井液关键外加剂优选评价方法

在充分调研国内外文献的基础上,结合具体的研究实践,提出了深水完井液关键外加剂优选的评价方法。对深水完井液盐类物质的筛选除了检测其实际结晶温度(TCT)外,还必须对其压力结晶温度(PCT)进行检测,PCT的测定是由专用设备通过测量系统温度和体积的变化来确定的;对完井液水合物抑制性能的评价方法一般采用温度-压力法,即通过试验过程中温度和压力的变化来判断气体水合物的生成与分解,从而判别抑制剂性能的好坏;对缓蚀剂的筛选除了采用常规的腐蚀失重法进行评价外,还必须进行应力腐蚀开裂试验评价。

Optimized Evaluation Method of Key Additives for Deepwater Completion Fluids

In addition to considering the density,crystallization temperature,compatibilities of reservoir rock with fluids,corrosion and environmental protection in the design of the usual deepwater completion fluids,the brine crystallization,formation of gas hydrate and stress corrosion cracking(SCC) of downhole metal materials should be considered due to the high pressure and low temperature in deepwater environment.The additives which provided special properties for deepwater completion fluids,such as salts and corrosion inhibitors,were the key additives.Based on the predecessors’studies,this paper puts forward the method for testing the key additives and the true crystallization temperature(TCT),the pressure crystallization temperature(PCT) should be tested in the selection of salts used in deepwater completion fluids.PCT is tested by a special apparatus for determining the PCT by the changes of temperature and volume of the system.The temperature / pressure method,which judges the formation and decomposition of hydrate by the changes of temperature and pressure in experiments,is used as the method to evaluate the hydrate inhibiting performance of deepwater completion fluids.The test of SCC should be conducted for the selection of corrosion inhibitors and conducting the regular weight-loss corrosion test.