Oil Well Testing Handbook
Providing real-life examples and cases, this resource contains the basics of well testing methods as well as all of the latest developments in the field, including testing for horizontal wells.
TABLE OF CONTENTS Oil Well Testing Handbook
Chapter 10: Application of Pressure Derivative in Oil Well Test Analysis
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 new dimensionless pressure derivative grouping (p' D t D/C D). Thus, this new approach has combined the most powerful aspects of the two previously distinct methods into a single-stage interpretive plot. Use of the pressure derivative with pressure behavior type curves reduces the uniqueness problem in type curve matching and gives greater confidence in the results. Features that are hardly visible on the Horner plot or that are hard to distinguish because of similarities between a reservoir system and another are easier to recognize on the pressure derivative plot.
10.2 Pressure Derivative Applications in Well Test Analysis
Figure 10-1 illustrates the application of pressure derivative to homogeneous reservoirs, naturally fractured reservoirs, and vertically fractured reservoirs.
Figure 10-1: Well with wellbore storage and skin in a homogeneous reservoir ( SPE, [J. Pet. Technol. Oct. 1988]). [1]
[1]Economides, C. E., "Use of the Pressure Derivative for Diagnosing Pressure-Transient Behavior", J. Pet. Technol. (Oct. 1988), 1280-1282.
10.3 Pressure Derivative Analysis Methods
Bourdet et al. [3] developed a new set of type curves (see Figure 10-2) based on the pressure and pressure derivative. In Figure 10-2, at early time, the curves follow a unit-slope log-log straight line. When infinite-acting radial flow is reached at late time, the curves become horizontal at a value of...
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