Abstract A study of overpressuring is presented for the fold belt and foreland basin of Papua New Guinea (PNG), where pore pressures are known to be highly variable and compartmentalized. The project was initiated to identify a methodology for predicting pore pressures in PNG, as all the standard approaches to pore- pressure prediction had failed to provide adequate estimates. Ten wells were selected for this study, including normally pressured and highly overpressured wells. Central to this study were the Hides field wells. Pore-pressure data are presented from formation pressure tests (repeat formation tests and drillstem tests) and from kicks calculated from mud weights and shut-in drill-pipe pressures. By designing an interactive database, the pressure data were analyzed with respect to topographic variations, the corresponding geology, drilling, and electrical logs and by using drilling events. The pressure regimes in the overburden and reservoir sections were generally found to be unrelated. The reservoir pressures were analyzed using different methods both to evaluate the source of the pressures and to quantify the pressures. The problems encountered with pressure prediction in the shales in this part of PNG are common to argillaceous sedimentary rocks in uplifted regions. These include the absence of a recognizable normal compaction trend from log data, the presence of uplift, the potential influence of fracturing and shearing on overpressure development and on the compaction trend, and a water table several hundred meters below the drill floor. Poor-quality log data, due to the presence of wellbore damage, exacerbates the difficulties of overpressure detection and quantification in the shale formations. Data from the Hides wells are used to illustrate the effect of wellbore instability on pore-pressure prediction from electrical logs. No obvious correlation was observed between the pore pressures and the shale sonic transit times, resistivity, or other electrical and drilling logs because the sedimentary rocks where kicks have been observed during drilling do not display significant log anomalies. Standard methodologies of pressure detection based predominantly on a porosity-related anomaly cannot therefore be applied effectively in this region. Comparing well data was complicated by differences of well elevations, formation depths, and thicknesses. The use of the appropriate datum for comparing pressure data is crucial in identifying the cause of the overpressures. A geomechanical approach was used to assess the sensitivity of electrical and drilling logs to the effective stress in the shales in an attempt to circumvent the problems raised by elevation differences and highly variable formation thicknesses. The advantage of using effective stress is that it corrects for the effect of topography on the pore-pressure data. Preliminary results show that the logs have a weak relationship with effective stress. The important lesson from this study is that conventional pore-pressure detection techniques in shales cannot be used with confidence in tectonically active regions. The development of an interactive database that captures significant events and conditions in offset wells has proved invaluable in understanding the complexity of the pore-pressure regime in the Hides region and its impact on drilling. The approaches adopted here move some way toward more effective pressure-detection methodology in complex geological areas.