The modern techniques of maintenance, repair and reconstruction of underwater oil and gas pipelines

Abstract

ough natural and artificial reservoirs, offshore oil and gas pipelines were analyzed. The modern detection
methods of waterworn sections in underwater oil and gas pipelines, the repair techniques of insulating covering
under water and new pipeline underwater insulation materials were studied. The analysis of innovative technologies
of addition and fixation of the waterworn, insufficiently buried sections of underwater pipelines were analyzed and
selected the most effective ones were singled out.
The authors considered the innovative technologies that can be used to eliminate the pipe wall defects in
coastal and streamway sections of underwater oil and gas pipelines. This is Aqua-Barrier system serving as a
portable temporary dam; the system makes it possible to dehydrate a small working area and drain 1,8 m deep
area; shaft wells, caissons, where corrosion defects are welded up and couplings are installed, replace defective
areas of oil and gas pipelines. The filling and sealing metal couplings, composite couplings, pipe elevation above
water, pulling a smaller diameter pipe into the defective pipeline (pipe-in-pipe method) techniques were studied.
The intratubal repair technique of hard-to-get-to sections, underwater passages of directional oil and gas pipelines and pipelines with microtunnels was proposed for application. The cases, when it is relevant to use a certain repair
technique were defined, their design features, advantage and disadvantages were considered, the constructive proposals
were made to eliminate complications during application.