1.0 Introduction
1.1 Overview of Well Testing
Well test analysis or pressure transient testing involves generating and measuring pressure variations with time in the well in order to estimate rock, fluid and well properties. Information that can be estimated from well testing include wellbore volume, damage and improvement; reservoir pressure (initial and average); permeability; porosity; reserves; reservoir and fluid discontinuities; and other related data1. These pieces of information are important in analyzing, improving, and forecasting reservoir performance. Well testing is considered essential in many phases of petroleum engineering.
Information from this test helps reservoir engineers analyze performance and predict future production under different operational mechanisms. Production engineers also utilize well test information to effectively combine injection and production wells in order to optimize reservoir performance. There are different well testing techniques such as pressure buildup, pressure drawdown, injectivity, falloff, interference and pulse tests. A single well can be used to perform well tests as well as multiple wells; these can be vertical wells, horizontal wells or a combination of both. This work focuses on interference testing in horizontal wells.
1.1.1 Interference Tests
When one well is shut-in and its pressure is measured while other wells in the reservoir are produced, the test is termed an interference test. The name comes from the fact that the pressure drop caused by the producing well(s) at the shut-in observation well “interferes with” the pressure at the observation well2. For this test, long duration rate modification in one well creates pressure interference in an observation well which can be analyzed for required reservoir properties.
1.1.2 Pulse Tests
Pulse Testing belongs to the family of multi-well testing methods. It requires the introduction of flow disturbances into a reservoir by alternately increasing and decreasing the flow rate at an active or pulsing well3. The effects of these shorter-rate pulses are investigated at the observation well. Each pulse can be an alternating period of production (or injection) and shut-in, with the same rate during each production or injection period.
…
