The inspection project encountered several challenges, requiring the experience of the CPS crew in collaboration with the inspection tool provider to devise several innovative modifications in each of the separate sections of pipe.

Section 2 required 3 tool runs (Gauge Pig, Caliper Pig and Smart Tool). There were challenges blowing the 2-disc bidirectional Caliper Pig down to the receiver end of the line as the discs on the pig distorted while moving through the 90° fittings on the risers. This allowed the compressed air to bypass the discs, immobilizing the bidirectional Caliper Pig. A 2-Conical Cup Tow Pig was constructed onsite using tool parts typically carried on Canline’s 40,000lb Pulling Technology Unit, affectionately called “The Wicked Winch”, that was paired to complete the project. The inspection on Section 2 was changed to a unidirectional run, using a centering ball to aid in the positioning of the pig through the 4, 90° fittings to the end riser.

In Section 1, the CPS crew loaded and launched the newly created Tow Pig from the previous run. The Tow Pig ran flawlessly for the entire 2 miles, but it stopped 50 feet from the end due to an undetected tee in the line that created an air bypass issue. The CPS crew modified the Tow Pig, extending the length by approximately 6”, adding an additional 2 cups to allow the additional length to span the void space created by the tee. The CPS crew was then able to complete all 3 runs in this section.

After successfully completing Section 2 and 1, CPS crew attempted to blow the CPS Tow Pig down to the launch end of Section 3. The pig navigated 4, 90° elbows and 2, 45° elbows, totaling 270° of bends. However, after inspecting the Gauge plate on the tow pig, it was discovered that two of the underground 90’s were possibly short radius, preventing the Smart Inspection Tools from passing through. Consequently, the run was completed as a bidirectional tethered run. Although there was air bypassing the discs on the bidirectional pigs, the Gauge and Caliper runs were successfully executed. During the last Magnetic Flux Leakage (MFL) run, the tool stopped 100 feet short of the target on a weld. It was critical the client survey the complete length of pipe as it is classified as a “high consequence area” due to the close proximity of housing. The solution involved the client opening another bleed-off valve at the far-end riser to reduce the high back pressure caused by air bypass around the pig. The pig moved another 44 feet and stopped again on the next weld. The CPS crew assessed the situation and decided to close the two bleed-off valves, one 2” and one 4”. They built up the air pressure in the entire pipeline to 50 psi, then reopened both blow-down valves simultaneously, enabling the Smart Pig to finish its data collection without further issue.