SPE Well Testing and Pressure Transient Analysis 2

Question 1

A pressure buildup test is shut in after a production time 'tp'. The Horner approximation works best when which condition is met?

Accepted Answer

Production time (tp) greatly exceeds shut-in time (Δt)

Answer

Shut-in time (Δt) greatly exceeds production time (tp)

Answer

Skin factor is zero

Answer

Wellbore storage coefficient is greater than 100

Question 2

Which reservoir boundary condition produces a doubling of the semi-log straight line slope in a buildup or drawdown pressure transient test?

Accepted Answer

A sealing fault (no-flow boundary) at some distance from the well

Answer

A constant pressure boundary (aquifer)

Answer

An infinite-acting reservoir

Answer

A high-permeability natural fracture network

Question 3

In a drill stem test (DST), the 'Initial Shut-In Pressure' (ISIP) measured at the start of the test is most useful for estimating which parameter?

Accepted Answer

Static reservoir pressure or pore pressure

Answer

Formation permeability

Answer

Skin damage around the wellbore

Answer

Wellbore storage coefficient

Question 4

What does the term 'pseudosteady-state flow' (PSS) describe in reservoir engineering and well testing?

Accepted Answer

Flow regime where reservoir pressure declines uniformly at a constant rate throughout the drainage area

Answer

Transient flow where pressure disturbance has not yet reached a boundary

Answer

Flow through a hydraulic fracture at constant bottomhole pressure

Answer

Multiphase flow in the near-wellbore region

Question 5

In a pressure falloff test performed on an injection well, which parameter can be derived using the same analytical methods as a standard buildup test?

Accepted Answer

Formation permeability and skin factor

Answer

Fracture gradient of the formation

Answer

Capillary pressure curves

Answer

Relative permeability endpoints

Question 6

Which deliverability test method for gas wells involves flowing the well at four different stabilized rates to establish a flow-after-flow curve?

Accepted Answer

Backpressure (flow-after-flow) test

Answer

Isochronal test

Answer

Modified isochronal test

Answer

Pressure buildup (Horner) test

Question 7

When analyzing a naturally fractured reservoir using pressure transient data, the Warren-Root model predicts what distinctive feature on the pressure derivative plot?

Accepted Answer

A dip (valley) in the derivative between two parallel semi-log straight lines

Answer

A unit-slope line indicating wellbore storage dominated flow

Answer

A doubling of slope indicating boundary effects

Answer

A constant half-slope indicating infinite conductivity fracture