Pressure Transient Behavior of Immiscible Water Alternating Gas (IWAG) Injection with and Without Relative Permeability Hysteresis Effects

Autor: Mustafa Onur, Azeb Demisi Habte, Ismail M. B. Saaid
Rok vydání: 2015
Předmět:
Zdroj: ICIPEG 2014 ISBN: 9789812873675
DOI: 10.1007/978-981-287-368-2_1
Popis: Pressure transient tests can provide useful information for characterization and evaluation of reservoirs under secondary and tertiary processes if properly designed and analyzed. There are a number of literature concerning the injectivity and falloff testing of water or gas injection wells. However, the information available on immiscible water alternating gas (IWAG) injection tests is limited to falloff tests without considering the effect of trapped gas. In this study, the pressure transient behavior of IWAG injection and falloff tests with and without relative permeability hysteresis effect is investigated using simulated pressure data. The saturation distribution shows that gas relative permeability hysteresis increases the recovery of oil in IWAG injection. At early times, the pressure response of gas injectivity test exhibits the properties of the gas zone which is in contrast to the water injectivity test. The pressure-derivative curve of gas falloff test exhibits a long transition period with a half-slope before the late time radial flow. The pressure and pressure-derivative curves of the water injectivity test display a unit-slope line at early times which can mislead to conclusion of wellbore storage effects. It is shown that the hysteresis has a significant effect on the pressure and pressure-derivative behavior of an injectivity test, but less effect on a falloff test.
Databáze: OpenAIRE