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PETRONAS has carried out a development drilling campaign phase-4 with a total of 5 (five) wells in the East Java basin area from year of 2021 until early 2023. Based on offset well data from previous drilling campaign, there were challenges that affect drilling efficiency. The challenge during drilling was high stick-slip in the LST-I formation with its characteristic as thick massive limestone. Stick-slip caused extremely high operating cost due to increased bit wear, decreased rate of penetration, increased wear of the bottom hole assembly and Logging While Drilling (LWD) tools and increased operating time for wiper trip to polish the tight spots which can cause high level of friction between Bottom Hole Assembly (BHA) and wellbore walls. At the same time, high stick-slip will also be worse at high inclination (> 60°) especially in intermediate section (12-1/4” Hole Size) and horizontal section in production section (8-1/2” Hole Size) with thick zones of massive limestone. To overcome this problem and to improve drilling efficiency in the drilling campaign, PETRONAS was utilizing Top Drive System (TDS) Soft Torque, which was also assisting to mitigate high drilling torque.

TDS Soft Torque w designed to enhance significantly drilling performance by preventing the stick-slip effect. The Soft Torque rotary system was based on the world-wide accepted Shell algorithm which was developed to counteract drill string fluctuation. The algorithm precisely calculated set parameters for the drive controller by considering the behavior and conditions of the drill string and drive system dynamics. The combinations of the Soft Torque rotary system and top drive acts as damper for torsional vibrations. This results in a significant reduction of torque fluctuations and stick-slip behavior which in turn increases the rate of penetrations, protects the drilling equipment and result in significant cost savings. The system is also available as a retrofit package that can installed easily in the existing drilling rigs.

By utilizing TDS Soft Torque, it was proven that rate of penetration in thick massive limestone LST-1 was higher than without using TDS Soft Torque. Stick-slip level was in medium to low level which reduce the fatigue level of drill string. It was also noted that bit dull record was better than without utilizing the Soft Torque. In general, TDS Soft Torque reduced drilling time significantly which equivalent to drilling cost efficiency. This paper will show the comparison of drilling performance for each anti stick-slip tool/equipment in order to reduce high/severe stick-slip.