North American Oil & Gas Pipelines

JUL-AUG 2018

North American Oil & Gas Pipelines covers the news shaping the business of oil and gas pipeline construction and maintenance in North America, including pipeline installation methods, integrity management innovations and managerial strategies.

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napipelines.com JULY/AUGUST 2 018 | North American Oil & Gas Pipelines 27 Triplet of Pilot Obstacles The initial concern arose when the local landowner moseyed over during rig setup and stated, "I hope this field doesn't flood 3 ft deep like it did the past two years right about this time. I'm hoping to get a soybean crop finally." Thankfully, the work area remained unflooded. How- ever, three of the five obstacles did occur during the pi- lot operations. First: It was observed that soil conditions were more variable than shown, and Gabe's encountered difficulty maintaining full drilling fluid returns back to the rig while piloting along the design profile. Unfortunately, drilling fluids started coming to the surface in an up- land area on the far side of the river away from the rig. After containing, pumping and trucking fluids back to the rig side for some time, approval was given to aban- don the 1,413 lf of pilot hole completed in soil and re- design the profile to enter the rock layer sooner to pro- vide additional overburden cover. Second: At the deeper alignment, Gabe's encountered a layer of expansive and naturally pressurized mate- rial that allowed drilling fluids to be absorbed into the surrounding soil, then was observed returning to the entry pit shortly after operations were shut down for the day. Gabe's held crew members on site overnight to maintain and store the returning fluids until the re- turned flow minimized. This cycle would result in up- wards of 31,000 gallons of drilling fluids, approximately the amount noted absent during operations, returning from the surrounding soils back into the entry pit with- in a 24-hour period. Third: Even with the deeper alignment, drilling fluids were especially determined to follow existing pathways of least resistance and continued to surface in the up- land area on the far side of the river. The pipeline opera- tor, Gabe's and Foltz determined that the best course of action was to continue forward with this pilot align- ment and install a fluid return line from that location back to the rig. Permitting a new HDD installation of a small diameter HDPE was too time-consuming. Luckily, an abandoned 16-in. steel pipeline river crossing was within the same right-of-way and owned by the same operator. With permission, Foltz excavated, benched downed to and opened the abandoned pipe on both sides of the river, and Gabe's mobilized a Vermeer 36x50 to rod through and pull in a 1,200 lf, 6-in. HDPE pipe. Drilling fluids were then able to be pumped through this 6-in. HDPE pipe, back to the rig's recycling unit. The pilot was then successfully completed. Rock con- ditions were encountered at 933 lf from the entry and ended 92 lf short of the exit. This resulted in 1,470 lf of the HDD to be in rock. Due to the setbacks during piloting, Gabe's began reaming on a 24-hours-per-day, 6-days-a-week basis to

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