This paper summarizes results from both coupon testing and full-scale testing directed at developing sealing systems to retrofit in traditional pipeline repair connectors and clamps so that they can undergo cycles of thermal heating and cooling without leakage. Significant findings from this effort are that elastomers extrude from seal cavities due to high thermally-induced swelling pressures exhibited by most elastomers, and that packer seals leak due to the loss of seal material. Coupon tests were conducted using elastomer discs to simulate the mechanics of full-scale packer seals of various grades used in pipeline repair tools. Finally, the project demonstrated effective sealing without high pressures and extrusion by using PTFE tape-wrapped die-cast graphite wedges to successfully seal against leaking and seeping of water and gas in annulus testing.
Ayers, R.R., Miller, J.E., Gage, E., Hebert, J., Wilson, I., “Effects of Thermal Cycling on Offshore Pipeline Repair Tool Seal Systems”, OTC-23143-MS, Offshore Technology Conference, April 30 – May 3, 2012, Houston, Texas, USA.