AAPG Middle East Region Geoscience Technology Workshop

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Two Kinds of Low Resistivity Pay Zones Identifications and Evaluations In South Sumatra Basin, Indonesia

Abstract

The South Sumatra Basin is the hydrocarbon prolific basin in Indonesia and also is one of highly explored basin. But in the recent years, some low resistivity zones are discovered in development wells. In this paper, two different kinds of low resistivity zones are showed in Low Tanglar Formation and Gumai formation. There are some strange phenomena in LRP zones in Low Tanglar formation. The resistivity of the pay zones is about 4 Ohhm. There is typical water zone according to regular petrophysical analysis, even water sample is collected by Formation tester. There are still high productive hydrocarbon zones proved by DST result. Further analysis showed reason of the low resistivity is because of deep invasion of high salinity mud according to well correlation and neighbor well production status. But the reason of the low resistivity zone in Gumai formation is different. The resistivity of pay zone is still 4 Ohhm with high gas reading. According to Petro physical composite analysis and well correlation, integrated by core analysis result. There are fine and glauconitic sandstone in Gumai Low resistivity pay zone, which caused high irreducible water saturation and low resistivity. The above low resistivity pay zones examples shows there are different reasons for LRP zones. The mud invasion correction is key for the LRP zones in Low Tanglar formation and high shale volume and high irreducible water saturation is key for the LRP zones in Gumai formation.