Pre-commissioning an oil and gas pipeline for field readiness requires a series of tests to ensure the structural integrity of the piping system before the final product is introduced. Chief among these procedures is the hydrotest, a pipeline flooding and pressurization process whereby water is introduced to test for leaks. Test water temperature must be stabilized and cooled to the pipeline’s organic temperature before the actual pressurization portion of the test can be initiated. The pipeline must then be drained and dried to complete the commissioning process.

One of the biggest challenges for pipeline construction companies is minimizing the time it takes to cool the test water. Hot ambient temperatures can result in water temperatures as high as 43.5 °C, and it can take up to 10 days for this water to stabilize to an acceptable temperature. Time spent waiting for test water to stabilize organically is often unacceptable to operators and their service companies, especially considering the high costs associated with keeping crews on-site.

Such was the case with an Aggreko customer when commissioning 4,600 feet of newly constructed pipeline in Texas. The water was stored on the surface in eight fracturing (frac) tanks, and its temperature needed to be reduced from 43.5 °F to 21 °C before flooding and pressurizing the pipeline. Once the hydrotest was completed, the water needed to be reflowed back into the frac tanks, and the full length of pipeline dried according to stringent moisture specifications.