SITUATION: To loosen a drill pipe that had been abandoned by a previous driller. The pipe was stuck about halfway under the Mississippi River as it flowed though the Memphis, Tennessee area.
METRICS: The overall drill pass under the river measures 4994 feet through jettable formations of clay and sand. Once installed, the 12-inch OD steel product pipe will be operational.
OWNER: Wespac Pipelines, Memphis LLC
CHALLENGE: Reconnect the drill pipe, unstick it, ream the already drilled hole, swab it and install the product pipe, all within a narrow time window.
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NARRATIVE:
Despite the best of computer analytics and an experienced crew, horizontal directional drilling (HDD) under a river like the Mississippi, mandates heavy duty drilling equipment and a confidence level that can be earned only by having done it.
Prime drill conditions at one drill site can quickly segue to difficult boring conditions, and all within a short distance apart. More than one driller has been confounded by these mercurial subterranean changes.
The opportunity in Memphis came to a head when in spite of repeated attempts, the previous drilling subcontractor was unable to dislodge a stuck drilling pipe. And that’s when Environmental Crossings, Inc. was called.
“From the sound of things, we knew we could do the job,” explains Bruce Brasher, ECI Vice President of Operations. “But we also knew it would take our best equipment and people.”
As an incentive to not only gain the work, but also to substantiate its credibility, the company bid the rescue on the basis of completing the project in record time. It agreed to an aggressive day rate contract of 27 calendar days to complete the HDD project, while also performing the requisite clean up of the drill site; and disassembling the drill string of the previous contractor. As it turned out, that gambit paid off.
Called in to oversee the job were two of ECI’s most experienced drilling staffers: The first, a superintendent with 25 years in the business, had dozens of projects and over 15 miles of underground pipe to his credit. The second, an actual driller, had accumulated 17 years of experience with ECI and over the past six years had completed 34 projects around the world. Together they were an integral part of the HDD teams that had accumulated a total of over 1,700 crossings worldwide.
On the morning of March 24th, 2007, they and their team rigged up to free the drill string and complete the project. At the working end of the drill pipe was Rig No. 10 (“Big Gun”). With a million pound pull capacity, by late morning of the following day the team had not only unstuck the pipe, but started pushing drill pipe from the existing bore and pulled a total of 62 joints!
Two days later all of the stuck pipe was out of the 4994 ft. hole; reaming operations were set up and the drill string was cleaned out. Swabbing and reaming operations consumed the next few days, and on the morning of April 10th the crew started pulling transport pipe through the drill hole. Late that afternoon the pipe was pulled.
The customary housekeeping issues of site restoration and equipment cleaning, in addition to breaking down the former drill pipe and stacking it, occupied the next week-and-a-half. And on April 20th, 2007, less than one month from the project start, and on schedule as predicted, the general contractor okayed the site and ECI’s remaining staff returned home.
“No doubt most of Memphis was unaware of what was going on under the river,” observes Bruce Brasher. “But the professionalism and efficiency demonstrated by our HDD team was yet another example of why ECI is regularly contracted to make some of the world’s most challenging underground crossings.”
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