Numerical Simulation of Tertiary CO2 Injection at Ivanić Oil Field, Croatia

摘要

Tertiary CO_2 injection is planned at Ivani(c) oil field, Croatia, inorder to recover some of more than 12×10~6 Sm~3 (75 MMSTB)of remaining oil in place. The field was discovered and put toproduction in 1963, secondary waterflooding was started in1972, and today the field is facing a considerable decline in oilproduction and an increasing water cut.A revised geological model of Ivani(c) field, based on 3Dseismic data acquired in 1998, was used as a ground forbuilding a full field numerical simulation model. 40 years ofproduction history were matched sucessfully by using blackoil formulation. Compositional simulation was applied for 18tertiary injection scenarios, which investigated impact ofnumber and position of injection wells, number of CO_2 slugs,and prior repressuring of the reservoir on the predictedproduction profile and final tertiary oil recovery. All tertiaryinjection cases were compared to the base case of continuedwaterflooding. Simulation results indicate possibility ofrecovering more than 2.5×10~6 Sm~3 (15.7 MMSTB) of incrementaloil in 20 years of future production.One of the possible sources of CO_2 is the gas treatmentplant in Molve, Croatia, which daily releases into atmospherelarge quantities of carbon dioxide extracted from natural gasproduced in northern Croatian gas fields. Sequestering a considerableamount of this CO_2 in Ivani(c) oil field is a welcomeadditional benefit of the planned tertiary injection project.