A new strongly inhibitive drilling luid system and its application to Dagu-1 well

A new strongly inhibitive drilling luid system is applied to solve the problem of sidewall stability of salt-gypsum beds and instable formations in Tahe Oilield. The basic formula of the system is determined and the laboratory experiment on the properties is conducted. Compatibility test is conducted on the emulsiied wax (RHJ-1), the emulsion polymer strength inhibitor (DS-301), and the well mud. The system is applied to Dagu-1 well, and the application result is analyzed. Research results show that the drilling system features in high compatibility with other drilling additives and strong inhibition, and prevents wellbore instability effectively. The suc- cessful application to Dagu-1 well is very important to the drilling operation in similar complex formations in the area.