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 14: Injection Well Transient Testing and Analysis
14.1 Introduction
This chapter presents pressure analysis techniques in injection wells. The injectivity test and the fall-off tests are used to estimate the reservoir properties of injection wells in waterflood and tertiary recovery projects. The knowledge of reservoir properties and near wellbore conditions in injection wells is as important as in the producing wells. Injection well transient testing and analysis are simple as long as the mobility ratio between the injected and in-situ fluids is about unity and the radius of investigation is not beyond the water (injected fluid) bank. Figure 14-1 shows types of tests, limitations, and their uses.
Figure 14-1: Types of tests, their uses, and methods of analysis
14.2 Injectivity Test Analysis Methods
Figure 14-2 shows rate schedule and pressure response for injectivity testing.
Figure 14-2: Rate schedule and pressure response in injectivity test
Under Steady-State Conditions
Reservoirs with injection wells can reach true steady-state condition when total injection rate is equal to total production rate. Hall [1] has provided a method to analyze injection wells that assumes a series of steady-state injection conditions (Figure 14-3). Figure 14-6 shows that a plot of integral or its approximation versus cumulative water injection should give a straight-line with slope:
Figure 14-3: Water injection well showing stimulation effects under steady-state condition Hall [1]
Methods of Analysis Hall Plot
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If P D and s 1 are known, then k/ ? can be estimated.
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If P D and k/ ? are known, we can...
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