Publications

Mahakam offshore wells are completed with both Gravel Pack and Cased-hole Completion. Progressive clean-up is required to start up the well and to avoid formation damage. Traditionally, well clean-up was performed through rig burner consuming 4 – 5 days of rig time. In order to reduce completion cost, alternative methods of clean-up are assessed without jeopardizing well integrity and productivity. Three alternatives of clean-up which are rig less, offline under cantilever and through production line were studied. Rig less clean-up can be performed by low-cost marine spread that offers significant saving compared to drilling rig. Offline clean-up requires simultaneous operation with drilling operation where safety concern shall be assessed in detail. Production line clean-up offers significant cost saving however some challenges i.e. eruptivity and surface line integrity shall be considered. Feasibility study of new clean up means were performed along with HAZID (Hazard Identification) & HAZOP (Hazardous Operation) workshop. Additional equipment, contract and operational cost are also evaluated to ensure excellent performance. By using retrofit stimulation vessel, rig less clean-up has been performed with significant cost and time saving. The main challenge was to retrofit clean-up equipment on compact stimulation vessel which was tackled by thorough study on marine, well operation and safety. As second phase of optimization, clean-up while drilling has been successfully conducted after detailed safety assessment including challenging layout for well intervention and well clean-up package. Finally, screening of wells allows selecting some candidate that can be flown directly through production line. This requires well eruptivity study and risk assessment of surface facility integrity. Special clean-up package was deployed to ensure no risk of erosion, corrosion and plugging from well effluent. To date over 20 days have been saved by using alternative clean-up methods. Well productivity and most importantly HSE objectives were successfully achieved.