Abstract

The Seria field was discovered in 1929 and the present development concentrates on infill drainage and secondary recovery. The field consists of a number of faulted blocks and stacked reservoirs.

At the end of 1984, 196 wells out of a total of 750 were closed in for poor production and are candidates for recompletion on poorly drained or undrained reservoirs or for abandonment.

Cased hole logs, the Thermal Decay Time (TDT) and the Gamma-ray Spectrometry Tool (GST), have been used to investigate the fluid content behind casing in old closed-in wells prior to abandoning the existing completion. The TDT is used to identify gas bearing intervals, to optimise the GST logging, and the GST is used to identify unproduced oil.

Zones identified hydrocarbon bearing from the original open hole electrical logs and confirmed oil bearing with the GST have been successfully completed.

New operational and interpretation techniques have been developed and are presented in this paper together with some field results.