Making Better Wells with Autonomous Inflow Control Valves for Water Control in the Flank of the Bretaña Norte Oilfield, Peru. A Case Study.

Abstract

Abstract Making better wells is paramount to provide better reservoir drainage, achieve higher oil production and improve recovery factors, while supporting Oil and Gas (O&G) companies in meeting their emissions reduction goals. Reservoir management is one the most impactful areas to reduce CO2 emissions and target lower carbon oil in the O&G industry, particularly for heavy oil fields with water drive mechanisms where significant energy consumption is related to unwanted water production, treatment, and reinjection. In the last decade, several operators in South America have applied various inflow control technologies to tackle this challenge. Bretaña Norte is a heavy-oil greenfield located in a remote area of north-east Peru (18-19 °API and 25 cP). After a few initial appraisal wells, the field development strategy was designed around horizontal wells and advanced completions with autonomous inflow control devices (AICD). The presence of a bottom aquifer provides a water drive mechanism with strong pressure support, but it causes water production to reach unacceptable levels, negatively impacting oil production and CO2 footprint. As a part of a technology evaluation program, the Autonomous Inflow Control Valve (AICV) technology was selected for field trials due to its ability to autonomously shut-off water, based on the fluid properties. A reservoir simulation study was conducted, and its expected performance was compared to other AICD technologies installed in the field, indicating potential benefits related to better reservoir management. The AICV completion was installed in a horizontal well placed in the lower flank of the reservoir structure which was deemed a challenging well position due to its proximity to the oil-water contact. After the initial well clean-up, the well began production with 2% BSW (basic sediments and water) and increased as expected until it reached 50%, where a change in slope of the BSW% trend was noted, suggesting that the AICV started to control the water influx. Total fluid production rate remained very stable with the ESP pump frequency held at the minimum speed. Another change in slope was noted at 70% when the well entered a water-cut stabilization phase. A ramp-up phase started after 1 year of production at 80% BSW, which illustrated the selective choking capabilities of the technology as the water cut has stabilized to maintain steady oil production. Production results have accurately matched initial forecasts obtained in the simulation study. Based on more than two years of production results, the AICV well has outperformed all other technologies installed in the right flank of the oil field. Production trends indicate that the cumulative oil production of the AICV well will be >15% higher after 475 days of production compared to other AICD wells, while drastically reducing the water production by more than 55% in the same production period (>3,500 MBbl). These results clearly demonstrate the added value of the technology in terms of effective water control and reservoir management. Emissions reductions have been estimated in >1.3 MM CO2 metric tons/yr/well and >5 MM CO2 metric tons/year/well savings compared to AICD completions and stand-alone screens (SAS) completions respectively, due to the lower energy consumption associated with reduced produced water volumes.