Experience Using the First Commercial Pad and Probe Style Formation Tester WhileDrilling Service Has Led To Value Creation at the Valhall Flank Development

摘要

GeoTap(R), a new formation testing while drilling (FTWD)service, was introduced to the Valhall Flank Drilling campaignin May 2003. Introduction of this service was anticipated to bethe most cost effective solution for gathering pressure data onthese long horizontal wells. After the first well, the equipmentwas modified; and the rate of success increased from 20% to90 %. As of November 2004, the service has been run inseven wells. In this paper, we review the value the service hasadded to the drilling campaign and also review the experiencegained with the service during its first year.The drilling environment is dynamic with hydrostaticpressure constantly changing. The new tool offers thecapability to perform pressure tests in this environment withthe mud pumps on or off. As an essential part of FTWD jobplanning, estimates are made concerning the impact ofhydrostatic pressure changes and supercharging prior tologging a well. In most cases, these estimates show thatpressure data gathered with this service compare favorably toother pressure measurements, such as those gathered duringperforating and stimulating.The field examples presented demonstrate the fieldprocedures used to gather pressure measurements and theadded value from acquiring this data during the drill phase.Knowledge of the reservoir pressure distribution in these wellswas crucial to understanding flow dynamics across the fieldand optimizing well decisions. These data have also impactedperforation and stimulation procedures that would not havebeen foreseen using conventional wireline tests. The data havebeen used to optimize the drilling process by providing keyinformation for the TD decision.Finally, conclusions are drawn regarding FTWDtechnology today and regarding its future direction for theValhall Flank drilling campaign in particular.