TABLE OF CONTENTS Detailed reservoir information is essential to the petroleum engineer in order to analyze the current behavior and future performance of the reservoir. Pressure transient testing is designed to provide the engineer with a quantitative analysis of the reservoir properties. A transient test is essentially conducted by creating a pressure disturbance in the reservoir and recording the pressure response at the wellbore, i.e., bottom-hole flowing pressure p wf, as a function of time. The pressure transient tests most commonly used in the petroleum industry include:
pressure drawdown;
pressure buildup;
multirate;
interference;
pulse;
drill stem (DST);
falloff;
injectivity;
step rate.
It should be pointed out that when the flow rate is changed and the pressure response is recorded in the same well, the test is called a single-well test. Drawdown, buildup, injectivity, falloff, and step-rate tests are examples of a single-well test. When the flow rate is changed in one well and the pressure response is measured in another well(s), the test is called a multiple-well test.
Several of the above listed tests are briefly described in the following sections.
It has long been recognized that the pressure behavior of a reservoir following a rate change directly reflects the geometry and flow properties of the reservoir. Some of the information that can be obtained from a well test includes:
| Drawdown tests | Pressure profile Reservoir behavior Permeability Skin Fracture length Reservoir limit... |
