Linear Time

Linear time or square root time, is used to analyze linear fracture or linear channel flow data. Linear fracture flow can occur in infinite conductivity fractures, and linear channel flow can occur in long, narrow reservoirs.

The constant rate solution for linear fracture flow data is:

For oil and water:

For gas:

The constant rate solution for linear channel flow data is:

For oil and water:

For gas:

Based on these definitions, linear flow data is displayed as a straight line on a plot of pressure versus square root time (p vs. Dt0.5). For a complex sequence of flow rates, the superposition linear time function is used instead.

For buildup data, linear equivalent time is used as defined below: