Z-Seal expandable metal sealing technology project
A plug of the size required by the operator was not yet available and specifications to meet the parameters were drafted. These included having a maximum run in and retrieval plug outer diameter (OD) of 5.20 in. (13 cm) for operation within the liner inner diameter (ID) of 6.184 in. (15.7 cm), effectively achieving a metal seal expansion ratio of some 119%, significantly greater than traditional elastomeric sealing elements. Pressure and temperature requirements were not enormous at 7500 psi and 230° F (110° C), respectively. Material selection for the plug and seal had to be commensurate with the particular wellbore environment including the stimulation acid and H2S, such that nickel alloys were selected in order to provide for enhanced chemical resistance. Another requirement of the seal was to conform to the stringent requirements of International Organization for Standardization (ISO) 14310 V0 qualification.
Operational deployment
Once development and lab testing including passing the V0 qualification were finished operational deployment was undertaken. After six installations, where only one run could be classified as 100% successful a moratorium was placed on the plug use pending detailed engineering and operational investigation and subsequent re-development work based on lessons learned and actual operational experience. A number of areas for improvement were identified and a project team put in place. This project team was multi-disciplined and housed over three continents. A number of the issues were minor in nature and were relatively minimal in terms of time requirements and complexity to resolve. The more complex issues related to what became apparent as those created from the significant shock seen during both the setting and releasing phases of plugging operation.
Operational issues
Previous Page
|
Next Page
Page 2 of 4
Volume 68 Issue 9
September 2008
Add RSS Feed