The permanent downhole pressure gauge is a class of tool recently harnessed in the industry. These tools are installed during the well completion and provide a continuous record of pressure changes during production. Permanent downhole gauges have the potential to provide more information than the traditional well test, which is carried out for a relatively short duration. Permanent downhole gauges may provide useful information regarding changes in reservoir properties or well condition with time as reservoir is produced.
However interpretation of permanent downhole gauge data is a new problem. Firstly, unlike the traditional well test where “disturbances” in reservoir (i.e. rates) are created and pressure and rates are both known, in the record from the permanent downhole gauge the changes in rates may not be properly known. Moreover, the dynamic changes in the reservoir, along with changes in the flowing temperature or in the gauge itself, make the data more complicated to interpret. Permanent downhole gauges are being applied widely now, yet there is still much to be done to capitalize fully on all the advantages they can offer.