Abstract
The purpose of this paper is to analyze the advantages and disadvantages of using modern Wireline Formation Tester (WFT) tools to refine the geological information and classify hydrocarbon reserves using an example from the Yamal Peninsula.
In order to meet the GKZ reserve classification requirements it is necessary to have production from the reservoir which was traditionally done with the help of open hole DST tools. It has recently been allowed to perform this task with WFT tools. In this paper we will consider a through casing application in a multi-layer reservoir. The combined use of WFT and DST allows us to contrast and compare both technologies.
As a result of this work we will show that the WFT can deliver similar quality information as the DST allowing us to acquire a C1 classification, determine fluid contacts and confirm saturations. The WFT offers the additional flexibility of testing ‘missed’ layers. There are also important differences to be noted, most significantly the higher resolution of the WFT allows pinpoint determination of contacts, however the relatively low flow rates and volumes usually does not allow us to determine reservoir boundaries. The combination of WFT and DST technologies offers the best picture of the reservoir.
