Predicting Future Gas Lift Performance in a Mature Water Flooded Field ASME/API Gas-Lift Workshop 12 – 13th November 2001 Aberdeen, Scotland Predicting Future Gas Lift Performance in a Mature Water Flooded Field Tony Liao & Simon Bishop, BP

Miller Field

Location of Miller Field

Miller Field Background Discovered in late 1982 Oil was found 4,000 meters beneath the seabed in a water depth of 100 meters The field lies 270km NE of Aberdeen Estimated 240 million barrels of recoverable oil and 480 billion cubic feet of associated gas

Miller Field Background Oil production commenced in May 1992 Gas production following about two months later Brae field has been on production since 1983 Reservoir pressure in Miller has declined while Brae has been produced

Objective Predict performance of Miller field if 4 of 9 naturaly flowing wells are converted to gas lifted Provide BU and partners performance data to make production management decision

Study Methodology Match production & injection history of Miller field Integrate reservoirs, wells, and surface network in a completed system Tune well models against well test data Generate vertical lift performance (VLP) curves for all naturally flowing & gas lifted wells Generate well IPR curves Generate well performance curves based on VLP & IPR curves Predict field performance under different operation strategies and system constraints

Miller Field Schematic

Multi-Reservoir Model Consideration Pressure data showed distinct trend in each compartment Geological description clearly supported a multi-tank system Single tank Mbal model was tested but history match was not as good

Miller Multi-Reservoir Mbal Model

History Matching: Southern Tank

Simulation

Application of Integrated Model Forecast production from every well, every tank, and the entire reservoir Forecast water injection to each tank Evaluate the impact of converting certain wells to gas lift at a specified time

Miller Integrated Model: Production Forecast

Gas Lift Well Performance Curves

Application of the Integrated Model

Application of Integrated Model

Conclusion Converting four wells from naturaly flowing to gas lifted will be beneficial for the Miller field Cumulative oil production incremental is 1 MMB over 4 years Integrated study provided Miller Business Unit with technical results required for reservoir management decision