Unlocking Subsurface Hidden Potential in Tempino Mature Field: Opportunity and Challenge

Abstract

Tempino structure is one of the brownfield structures in Jambi. Air Benakat and Gumai Formation have been producing hydrocarbon since 1920s and currently the Tempino structure contributes about 900 BOPD to the oil production of Jambi Field. There are 218 wells in Tempino before the success of drilling T-219 well in 2021. The T-219 well produced more than 400 BOPD from the Gumai Formation as confirmed the hydrocarbon potential in central block, to be followed by 7 approved-wells proposed to be drilled in 2022-2023, a most aggressive activity in Tempino in the last 20 years. Only about 13 wells of Tempino’s wells penetrated the Gumai Formation. The drawback in assessing subsurface was due to data (availability, quality, and comprehensiveness) to the production analogue, as there was no particular problem with the reservoir distribution. Three simple ideas of well profile mapping, selective layer perforation method, and fracturing design are lessons learned from many wells whose performance was not as expected, ideas which were then implemented in T-219 wells. The data acquisition result of T-219 well was surprisingly indicating that the Gumai sand had oil occurrence, near virgin formation pressure, and around 20 meters shallower than estimated. The updated static and dynamic model showed a significant change to the previous model, as vertical seismic profiling (VSP) and pressure test data played a massive role. The latest model shows great potential of central block of Tempino, where T-219 well was placed. In contrast to the T-219 well, it is assumed that the following wells will have better properties and the production forecast with low uncertainty case. On the other hand, there is still a big question to be answered, as more than 100 meters of Gumai sand is considered to have vertical barrier as the porosity log shows several streaks of more-dense materials in the midst of the sand. When this question is resolved, the Gumai sand in Tempino will probably have a bigger estimate of hydrocarbon potential. The Lessons learned of this success story in discovering hydrocarbon in a mature field is to implement a novel approach and learn from the ideas of previous well proposals.