Permeability is the cornerstone of any reservoir-flow modeling that leads to field development and production management. Typical sources of permeability include cores, logs, wireline formation tests [or minidrillstem tests (mini-DSTs)], and conventional DSTs. However, integrating various sources of permeability at different scales is problematic. Anchored in mini-DST-derived permeability, this study endeavors to integrate various sources of permeability, leading to reservoir description in a turbidite sandstone reservoir in the Sabah basin, Malaysia.
Pressure-transient-test data recorded during a mini-DST operation differed significantly from data gathered during a conventional DST. Even though test quality was excellent, interpretation challenges were numerous in this well. Consequently, multidisciplinary information was brought to bear for integration of data derived from mini-DSTs. Other sources of information included sidewall cores, spot pressure measurements, nuclear magnetic resonance (NMR), and microelectrical imaging logs. This case study demonstrates that, in this particular setting, the use of mini-DSTs was cost-effective and yielded the subsurface information required to plan field-development options.