Effect of Oil Production Rate Profile and Production Time to Pressure Buildup Test Analysis

Determining of reservoir characteristics is parameter that needed in reservoir description. One of method to know reservoir characterisctics is Pressure Transient Analysis that is called Pressure Build-up Test. This method is based on superposition principle where need a simplified production rate and production time. Parameter of characteristics on Pressure Transient Analysis can be observed from horner plot, semi-log plot, derivative pressure and type curve matching. It is supported by geological, petrophysics, laboratorium and logging data. Parameters that can be known from Pressure Build-up test are permeability reservoir, skin, wellbore storage, reservoir aspect (model), boundary, average pressure (finite acting). To get the best result which representate reservoir condition,so it's proven by making hipotetic reservoir model as bounded (closed) reservoir.

Result of this analysis well testing shows that when pressure build-up test is tested without produce in constant rate before the test, so recomanded production rate which is most appropriate with reservoir condition is values of last rate production (qlast). Using (qlast) on production time equivalent can be applied because it produces same values. However, if We use all modified (multiple) rate, results will produce the values that is not appropriate with reservoir condition. If we test by producing on constant rate before the test, so recomanded production time is from the beginning of production not only from time of last constant rate. If we test by closing the well and produce on constant rate before the test, so recomanded production time is only since time of constant rate condition, not from the beginning of production. Wrong using of production rate and production time will produce different interpretation. more detail..
colected @abrar2009