The Importance of Thread Compound Rheological Investigations in Providing Long Term Leak Resistance of Threaded Connections

摘要

Drilling and production activities use threaded connections to create long drill, casing or tubing strings. Thread compounds are used to protect the threads from galling and to ensure a constant and reliable friction coefficient, but also in some connections like API tubing and casing to seal the connection during the production phase. In thermal enhanced oil recovery processes, high temperatures are used to enhance the production. While the temperature of the injection fluids may exceed 300 °C, the production wells have a lower production temperature. This article shows for the first time unique experiments on thread compound viscosity as a function of temperature. The results show a dramatic change of the thread compound viscosity that affects its sealability function. The reduced viscosity of the thread compound changes the leak resistance of the tubulars used in thermal wells if they rely on the material to seal. Furthermore, we observed that some compounds lose their integrity at around 70 °C, which may also affect the break out behavior of the pipe connections.