BP's down hole instrumentation of the Khazzan tight gas appraisal wells provides a rare opportunity to quantify reservoir pressure and temperature dynamics. Several appraisal wells were initially tested for 3-4 weeks and subsequently shut-in for about a year. The continuous downhole gauge recordings of the resulting pressure build ups were then analyzed to quantify understanding of stimulation effectiveness, reservoir quality away from the wellbore, total producible connected gas, geomechanics and wellbore hydraulics. History matching of this gauge data provided confidence in predicting production profiles for full field development. This paper examines the pressure transient analysis (PTA) of one representative well in the field. The high quality build-up indicated that good quality rock extends to beyond the radius of investigation of the pressure transient and PTA did not reveal any barriers in an area of ~20 sq. km around the wellbore. The absence of boundaries and the possible extension of better quality reservoir have given BP the confidence to place an additional (and successful) appraisal well in the southwest of the block, thus extending the area that potentially will be a focus for early full field development. Installing permanent down hole gauges carried a high initial cost, but the value gained in quantifying subsurface uncertainty has proven the success of this technology application. It has also proved invaluable in executing hydraulic fracture stimulation. This high quality information boosts confidence in reservoir performance and long term deliverability leading to better informed business decisions regarding potential full field development.

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