Publications

The Anambas Block in Offshore Natuna has witnessed a gas discovery first time in Lower Gabus formation from recently drilled well. Detailed Geomechanical modeling for well planning and implementing operational excellence during execution was the key behind this success. The main objective was to minimize the risk of lost in hole, finish the well within time & budget and drill the well safely with minimum spent on Non-Productive time. Considering an exploration setting, limited information availability from nearby offset wells to construct the geomechanical model was one of the main challenges. However, it was initiated as outmost priority to perform the pre-drill wellbore stability for well planning using regional understanding and post drilling updates with newly acquired data for further operational decisions.

This paper describes how initial 1D geomechanical model was built using limited available data from two offset wells (Well X drilled 1971 and Well Y drilled 2006) in Anambas Block and regional experiences. The model was used to perform pre-drill wellbore stability of well Z to optimize the drilling plan and minimize non-productive times related to borehole stability. Then the model was subsequently updated during drilling using the latest drilling and petrophysical information gathered from this new well. This during drilling update was utilized for the well deepening program which also provided a positive upside to the original well objectives and identified potential for further exploration opportunities in the deeper formations.

The outcomes and recommendations of this study were meticulously followed by drilling team during drilling the original well and for decision making while drilling the additional deepen section. The well was drilled deeper with full data acquisition and tested successfully which contributed to the well discovery. This effort contributed to operator’s success in an offshore exploration campaign by timely execution, under budget and with no reported HSE events.