In the upstream oil and gas production sector, unplanned production deferment (UPD) is defined as the conduit production flow deviation from technical potential due to unscheduled interruptions. Low UPD is a key indicator of a facility's operational excellence. High UPD reflects that a facility is facing frequent downtime of critical equipment, poor work schedule planning and execution, under-performing producer wells, inability to meet the facility's production targets, increased expenditure, as well as possible additional work-related stress among the employees. In this case study, UPD of a Malaysian upstream brownfield production facility is mostly affected by wells-related (33%), process-related (31%), and rotating equipment (25%). A clear framework has to be in place to resolve and address the UPD, with improvement recommendations detailed out for deliberation. The outcomes of UPD reduction efforts heavily depend on the integration as well as collaboration of people, processes and technology.