The Tangguh LNG gas fields are situated in the Berau Bay, Irian Jaya, Indonesia. An extensive exploration and appraisal program was performed from1994 to 1998 which resulted in the discovery of 14.4 TCF of proved gas reserveswith substantial upside reserve potential. The fields are currently at thedevelopment planning stage in support of the Tangguh LNG project, Indonesia'sthird major LNG center.

The objective of this work was to obtain a more accurate skin and non-Darcycoefficient (D) from exploration and appraisal well tests by accounting forcompletion effects. The impact of corrected D coefficient on welldeliverability reduced the number of forecasted development wells.

In Tangguh pressure transient analyses, skin and D coefficient from welltests were first calculated based on pressure data from gauge depth. Most ofthe gauges were placed in gauge carriers integral to the test string andanywhere from 125 to 300 feet above the mid-point of producing interval.Because the pressure drop in the completion from the perforations to the gaugeappears as additional skin, the deliverability of the formation could beunderestimated if this effect were not considered in the analysis.

After the pressure drop in the completion was correctly accounted for, thenon-Darcy coefficient decreased in all wells. The D coefficient correction wasparticularly significant in high transmissibility reservoirs and agreed withtheoretical D coefficient calculations. This increased the predicted gas welldeliverability.

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