Publications

Beta Field is a mature waterflood development in the Central Sumatra Basin, Indonesia, with the first production development in 1972 and the first water injection in 1992. The majority of field production has historically been from the Delta formation. Tango formation has had a long history of development under primary depletion beginning in 1977, typically as a vertically commingled secondary development target relative to the deeper Delta formation which has larger reserves and generally higher reservoir quality.

The initial five years of Tango production was consisted entirely of oil, with 0% watercut. In 1997, fluid production was ramped up with the sequential completion of up to 12 wells by 2004. However, in 2000 production began a continuous decline, and by 2010 the further development and re-completion activities in the Tango Formation were minimal due to activity being focused on primary production from the Delta reservoirs group. By early 2017, reservoir pressure in the Tango formation reached the minimum (fluid level) required to sustain fluid production using artificial lift by ESPs. However, reservoir-level watercut remained low at approximately 80%. At the start of the Tango optimization campaign in mid-2017, beginning with pressure restoration at three flank locations from vertical expansion of the existing waterflood, the Fluid in Fluid Out (FIFO) ratio remained subnormal due to massive infill producer drilling campaign in 2021-2022.

A comprehensive study and analysis using 3D reservoir simulation were conducted to evaluate the optimum waterflood management strategy for the Tango Sand and resulting to recommend drilling six new injector wells in the optimized locations. Based on the recent performance from existing producer wells, the newly drilled injectors proven to correspond to an incremental increase in oil production.