Breakthrough Application of Encapsulated NaCl Polyamine High Performance Water Based Drilling Fluids System in Mahakam Field, Indonesia
Keywords:
Drilling fluids, drilling; polyamine, drilling fluid chemistry, drilling fluid formulation, surface section, shale, inhibitionAbstract
Pertamina Hulu Mahakam (PHM), operating in Mahakam Field, has been drilling 321 wells for swamp operation and 73 wells for offshore operation. Surface section of the wells were drilled using conventional Potassium Chloride (KCl) Polymer System as inhibitive drilling fluids is needed to overcome reactive clay formation. Failed to overcome reactive clay might cause wellbore instability problems which will increase potential shallow gas hazard. However, in 2022, price of KCl has soared to highest level by 200% increased due to its scarcity. This is a consequence of ongoing political issue happened in Belarus. The challenge presented as alternative water-based system should be implemented to replace KCl Polymer System to maintain well cost economically.
Study of Encapsulated Sodium Chloride (NaCl) High Performance Water-based Mud (HPWBM) System has been executed as an alternative to KCl Polymer System. The basic idea is to replace shale inhibition method from using Potassium Chloride to Polyamine. Extensive laboratory testing was carried out to evaluate the performance of Encapsulated NaCl HPWBM and ensure it can generate similar or better performance compared to KCl/polymer system. Using cutting samples from Sisi field, KCl Polymer Mud and Encapsulated NaCl HPWBM with various concentration are prepared and tested to evaluate its inhibition performance. X-ray diffraction (XRD) and Cation Exchange Capacity (CEC) analysis were conducted to identify the type, relative amount, and reactivity of shale minerals present in sample. Encapsulated NaCl HPWBM System has been applied successfully in 12 trial wells on offshore operation with total depth up to 1,800 meters. Through the implementation of Encapsulated NaCl HPWBM, dilution rate has vastly reduced by over 78% and hence, cost saving over $180K has been achieved. This has shown potential cost efficiency with more surface section to be drilled in this year.
