Managing Field Production Decline Through Optimization Efforts

Abstract

Field X is located in the Gulf of Guinea. The field development strategy involved mid-flank oil production, peripheral water injection and crestal produced gas reinjection to enhance recovery from pressure maintenance and improved sweep efficiency in addition to compliance with a "No Flares" policy. The field's wells have cased hole frac-pack with intelligent completions (downhole gauges & interval control valves) enabling zonal control and real-time monitoring of pressures and temperatures. Drilling and completions of the wells in the field were executed in five (5) phases with the last well brought online in July 2019. Typical of mature field without developmental or infill drilling activities in the last six years, the field started experiencing natural production decline post 2019 drilling campaign. The decline in field production was exacerbated with increasing produced water, produced gas, sand production, and riser slugging. Additionally, Field X's oil production is further constrained by available gas compression capacity because the facility operates under a Zero Routine Flaring (ZRF) philosophy. All these challenges require innovative and proactive solutions with a focus on operational excellence and sound reservoir management practices. To address these challenges, the asset team leveraged existing Digital Oilfield (DOF) infrastructure and robust well Surveillance, Analyses & Optimization (SA&O). The DOF platform provides real-time data streaming, enabling proactive optimizations. To address natural field decline and optimal utilization of Field X installed (subsurface/subsea/surface) capacities, the asset team has embarked on various ingenious interventions to manage field oil production decline through rigless production enhancement activities. These interventions include acid stimulation (production uplift & completion preservation), reactivation of shut-in wells, Rate Change Protocols (RCP), Marginal Gas Oil Ratio (MGOR) testing, production riser re-alignment, Sand Free Rate (SFR) and sound reservoir management practices through balanced water/gas injection. Working cross-functionally (asset, operations, subsea, facilities, wells, etc.), robust production constraints management, continuous lookback for lessons learned and adoption of best practices were critical to successfully arresting production decline in Field X. Over the last five years, fifty (50) production optimization initiatives have been successfully executed with average annualized yearly production adds of ~7,730 BOPD and this has helped to flatten field decline rate to single digits. This technical work highlights all these production optimization efforts, best practices, and lessons learned from Field X.