An Education In Offshore Pipeline Construction. By Allyn Stott In the mid 1980s I had an opportunity to visit an offshore pipeline laying barge. Fortunately the weather was clear, warm, and just about perfect. We left early from Houston that day and arrived in Port Arthur in about two hours. I believe we met our transportation in the Brown and Root staging area. Our ride to the offshore pipe laying barge Within about 10 minutes after our arrival at B & R s facility, a helicopter landed on the outside of the fenced area where we were waiting. The pilot saw us and effectively hopped the helicopter over the fence and landed near us. After some paper work, we were ready to go. The pilot s last instructions prior to take-off were: If we should go down in the water, don t inflate your life preserver until after you leave the helicopter. This was a reassuring thought for the trip. The ride to the barge took perhaps 30 minutes and it was reassuring that the pilot could find that tiny barge in the vast area of the Gulf. Once airborne, we were able to see many idle jack-up-rigs in the Sabine River.
Drilling rigs idle in the Sabine River. Shortly after leaving the comfort of dry land and entering the skies above the Gulf, the pilot advised us that the small object on the surface was where we would spend the day. First view of the pipe laying barge (It looks so small).
A closer view of the pipe laying barge (lay barge) and its smaller supply barge. As we arrived at the barge, the pilot had to synchronize the helicopter with the rise and fall of the barge due to the water wave action. When we arrived, the water was relatively calm. The barge was a self-contained small town with sleeping areas, eating facilities, laundry, and the equipment to build a pipeline. They also had a library of videos for entertainment during non-working hours. We also met the Captain and several of the crew. In addition, I was introduced to the man that ran the laundry. Since I didn t speak Spanish, the engineer with me introduced me to him. Later, I learned that he told him that I was with the INS (Immigration and Naturalization Service). We didn t see him after that! The barge operation was ingenious. It had four sea anchors positioned off the four corners of the barge. By slightly adjusting the length of the anchor lines, the Captain is able to hold his position in the Gulf while adding the next section of pipe to the line under construction. The barge had a GPS monitor that allowed precise mapping of the pipe location for future work. When the anchor cable ran out, a tug boat would move the anchor forward and the crew would adjust the cable. This technique allowed the barge to remain in the same position until the next section of pipe was welded and ready to be put in the water. After welding each section of pipe, it was necessary to x-ray the weld to verify its integrity. It is easier to fix a weld before the pipe is put in the water. The x-ray machine was positioned on the pipe just above the weld. The x-ray camera would rotate around the pipe while photographing it. The image was developed and checked by an engineer and then the welded connection was coated with a rust resistant coating before lowering the pipe section into the water.. I am sure all these images are preserved in a file somewhere for possible future reference.
The bridge of the barge is its control center. Also, this particular section of pipe includes a cut-off valve (or side valve) installed on one segment of pipe (a pipe joint). Crain bringing pipe joints from the supply barge to the lay barge work area. Note the supply barge is moving up and down due to a shift in the wind. The Captain repositioned the barge to eliminate the crashing of the supply barge into the larger barge.
At one time the deck of the supply barge was a few feet above the deck of the lay barge. Then moments later, the deck on the supply barge was ten feet below the lay barge deck. I watched the crew transfer to the supply barge and load several pipe joints to the lay barge. I found one occupation I didn t want to do! Crew moving pipe sections to lay barge. This picture is looking down at the top of the pipes on the supply barge. The previous three pictures show the instability of the supply barge caused by the wave action in the Gulf.
Outside of the previously mentioned normal pipe coating, this pipe was also coated with a layer of concrete. The thickness of the concrete depends on the pipe diameter. The resulting weight of the concrete coating and the pipe causes the pipe to lay on the sea bed and prevents it from floating. Several pipe joints in staging area on barge This picture shows the concrete coating a little better. The ends of the steel pipe joints are cleaned and smoothed as needed for the welding process to the next joint. It is easy to see how the two pipe joints have been welded together.
The concrete coated pipe was laid on these rollers. After a completing a weld and coating, the lay barge moved forward causing the last pipe joint welded to be moved towards the back of the lay barge and subsequent entry into the Gulf, During the assembly process, the pipe sections are cleaned, welded, x-rayed for weld quality, coated, and finally moved into the Gulf. This picture shows where the cut-off / side valve joint was welded (no concrete pipe coating). During the pipeline construction, a cut-off valve / side valve is installed where it will connect to another pipeline. During our time on the barge, one of the cut off valves was installed in the line.
Section of pipe with prefabricated cut-off valve / side valve being positioned. Crew checking the installation of the cut-off valve / side valve into the pipeline.
When a valve is installed in the pipeline, a diver follows it to the floor of the Gulf to ensure it is positioned correctly. A discussion about the finer aspects of pipe laying (Note that safety helmets are always worn on deck.)
Unfortunately, I didn t receive a copy of his picture! Machinery to maintain position in Gulf.
The pilot said he would be back. Just in time as the weather is closing in. Our ride back to shore. The helicopter landing on a barge is a sight to see. The pilot must make the helicopter rise and fall with the platform on the barge. Then when he is synchronized with the motion of the platform, he lands with minimum stress on the helicopter or the platform. The day was a fabulous experience. I have a better appreciation for the men that construct pipelines, especially offshore. The quality of food at lunch was high and the size of the portion was large. Overall it was a super day that I won t forget. I do think I will continue working with computers, on dry land, in an air-conditioned office, and a little closer to home.