Analysis of Transient Pressure Tests for Olkaria Exploration Wells

Abstract

Analysis of transient pressure tests for Olkaria West wells shows that both infinite acting and double porosity models can be used to analyse the well behaviour and infer reservoir properties from fall-off steps of long enough duration, in wells where no siginificant thermal recovery occurs. The double porosity model gives better estimates of reservoir properties than the infinite acting model, for long fall-off steps in wells intercepting fractures. Semilog methods give fairly good estimates of reservoir transmissivity for the long fall-off steps but are highly inaccurate when used independently, especially for the short fall-off steps conducted in most of the wells. Double porosity models can also be used for recovery test analyses where two phase transients are not siginificant.