Block 61 Drilling Fluids Optimization Journey

Abstract

BP operates Khazzan & Ghazeer fields in the Sultanate of Oman with the aim to deliver safe, reliable and efficient wells. Efficiencies within drilling fluids design form part of a greater continuous improvement cycle to well delivery cost. With fluids spend contributing to a significant portion of the executed well cost (typically 15 % in Oman), fluids design changes hold the potential to yield positive cost savings (where well performance is maintained). This paper presents the areas of fluids design which were explored to reduce fluids spend as part of the continuous improvement cycle. Combined, the changes to fluids design evolved to reduce the fluids cost of Barik vertical wells to 6% of total well cost. All avenues of fluids design and the costs associated with the fluids operation in Oman were viewed as being in scope for change to maintain overbalance hydrostatic pressure on fluids spend. The methodology employed to reduce fluids spend can be described in four steps as per continuous improvement roadmaps; identify the cost saving project, the key enablers which allow the cost saving to be realized, risk/reward analysis where low risk/high reward projects were accelerated as priority and placed to the front of the queue for field trial and where a trial outcome is positive, the change is introduced permanently to the operation. This process worked well in continuously pushing fluid performance and reducing the fluids spend in Oman. The scope of change to fluids design was wide, with each ‘value adding project’ providing its own cumulative cost benefit. The projects which contributed to significantly reducing the overall fluids spend in Oman focused on personnel, fluid type selection, fluids formulation optimization, wellbore strengthening, fluid consumption and recycling, drilling fluids practice and brine selection. Reductions in fluids spend were accompanied with an improved well performance. Well delivery times being continuously observed to improve throughout the campaign (63 days vs 42 days). Whilst the fluids design is not directly responsible for this outcome, it does highlight that the changes made to fluids design positively influenced the improved well delivery performance. The drilling fluids optimization initiatives resulted in significant time and cost saving thus reduction in overall Barik vertical well drilling cost. Drilling fluids cost is reduced by over 55% without impact on safety and drilling performance.