From Advanced Reservoir Engineering

1.5 Pressure Derivative Method

The type curve approach for the analysis of well testing data was developed to allow for the identification of flow regimes during the wellbore storage-dominated period and the infinite-acting radial flow. As illustrated through Example 1.31, it can be used to estimate the reservoir properties and wellbore condition. However, because of the similarity of curves shapes, it is difficult to obtain a unique solution. As shown in Figure 1.49, all type curves have very similar shapes for high values of C De 2 s which lead to the problem of finding a unique match by a simple comparison of shapes and determining the correct values of k, s, and C.

Tiab and Kumar (1980) and Bourdet et al. (1983) addressed the problem of identifying the correct flow regime and selecting the proper interpretation model. Bourdet and his co-authors proposed that flow regimes can have clear characteristic shapes if the pressure derivative rather than pressure is plotted versus time on the log log coordinates. Since the introduction of the pressure derivative type curve, well testing analysis has been greatly enhanced by its use. The use of this pressure derivative type curve offers the following advantages:

  • Heterogeneities hardly visible on the conventional plot of well testing data are amplified on the derivative plot.

  • Flow regimes have clear characteristic shapes on the derivative plot.

  • The derivative plot is able to display in a single graph many separate characteristics that would...

Products & Services
Flow Controllers
Flow controllers monitor and maintain flow-rate variables, typically in process applications.
Turbine Flow Meters
Turbine flow meters measure the rate of flow in a pipe or process line via a rotor that spins as the media passes through its blades.
Liquid Handling Pumps
Industrial liquid handling pumps are classified in many different ways, and are distinguished by the media pumped and the fluid motive mechanism (dynamic or displacement).
Pressure Sensors
Pressure sensors include all sensors, transducers and elements that produce an electrical signal proportional to pressure or changes in pressure.
Pump Controllers
Pump controllers monitor flow and/or level variables, and control a pump accordingly to maintain the desired levels. Pump control can include simply turning a pump on and off, or more advanced controls for pump speed, output pressure, etc.

Topics of Interest

1.6 Interference and Pulse Tests When the flow rate is changed and the pressure response is recorded in the same well, the test is called a single-well test. Examples of single-well tests are...

9.1 Introduction The pressure derivative application to gas well test analysis involves the combined use of existing type curves in both the conventional dimensionless pressure form ( P D) and the...

10.1 Introduction The pressure derivative application in oil well test analysis involves the combined use of existing type curves in both the conventional dimensionless pressure form (p D ) and the...

6.2 Pressure Buildup Behavior Curves Figure 6 2 shows pressure buildup curve shapes. As also shown in that figure, the fracture cases and large negative skin cases approach the semilog straight line...

11.1 Introduction This chapter discusses the quantitative use and applications of type curves in gas well test analysis. The most generally useful type curves have been selected and are included...