Abstract
Kharyaga Object 2 is an oil bearing reservoir with a gross thickness of 160-250m deposited on a rimmed shelf system. Two domains can be distinguished: the platform margin (the barrier domain), highly fractured and karstified, and the platform interior (the back-barrier domain), almost fault and fracture-free, non-karstified, and which shows a matricial behavior. Both domains are developed.
As per current vision, flow behavior in the barrier part is mainly controlled by different dissolution features and a complex secondary porosity network. Field development started in 1999 and significant amounts of data were acquired (extensive use of down-hole gauges – MDT – PLT, well tests, interference tests, etc.). Integration of new data into the dynamic model required a rigorous history match process and an efficient workflow with a permanent link to the geological vision. A progressive match by steps (conductivity Å static pressure Å watercut Å vertical inflow performance Å well interference) helped to avoid being overwhelmed by the amount of data to be matched.
This elaborated matching scheme permitted, as a result, to distinguish and reveal the impact of all types of heterogeneities on the matching process (matrix, karst or fracture dominated) and calibrate a complex representation with a dual medium (matrix and secondary media, the latter merging various types of karst, faults and fractures).
Representing properly the field complexity required a significant number of cells, as well as the use of specific mechanisms (imbibition with hysteresis and gravity drainage). To simulate such sophisticated representations in a reasonable time, a new powerful software and high computational power were required.
As a result of the smart use of acquired data for the calibration of the dynamic model, a powerful tool for reliable production forecast and business management was developed.
