Publications

Discovered in 1944 and producing since 1952, Minas has produced 4.4 billion barrels of oil for a recovery of 51 percent. Current production is 99 MBOPD and 5 MMBW/D (water cut = 98 percent). All produced water is injected into the reservoir and into disposal wells for zero water discharge.Primary production was aquifer-supported until the early 1970s when Caltex Pacific Indonesia (CPI) initiated a peripheral waterflood for pressure maintenance purposes. Next came an investmentintensive pattern waterflood (PWF) from 1993 to 2000 where hundreds of producers and injectors were drilled on 71-acre inverted 7-spot patterns.Despite all the drilling, Minas experienced a steep production decline in the late 1990s. Starting in late 2000 there was a renewed focus on waterflood management practices: water shut-offs, a reduction in commingled completions, and injector-producer alignment. High-resolution seismic significantly improved the success of infill drilling programs. An alliance improved the performance of the electricsubmersible pumps (ESPs). Reliability and operational excellence initiatives commenced with the facilities, operations and maintenance groups.The results have been dramatic. The oil decline rate flattened from 25 percent in 2000 to two percent in 2004 while infill drilling dropped by 85 percent.Water production and associated energy consumption decreased significantly. Run times for the ESPs increased by 50 percent, and more revenue came from less lost production combined with reduced operating expenses. Gas compressor uptime increased and unscheduled downtime decreased. The maintenance group started a proactive efficiency campaign and notably exceeded their target. Downtime of the electricity supply decreased. The reserves replacement ratio for 2004 was well over 100 percent. Minas is starting to change from a very mature waterflood to an asset with continued waterflood potential.