Flow line bundle and method of towing same

Abstract

A flow line bundle assembly includes a plurality of conduits disposed within a tubular covering member. The tubular covering member is sealed at its ends before being placed in a body of water, so that the flow line bundle has a slight positive buoyancy when submerged in the body of water. Weights are then added to the flow line bundle to cause it to have a neutral buoyancy at a position slightly above a floor of the body of water. The flow line bundle is then towed from its point of construction, through the body of water, to the location where it is to be installed. During a first method of towing, if an obstacle located above the ocean floor is approached, a trailing tug increases a restraining force applied to the flow line bundle so as to lift it above the obstacle as the flow line bundle passes over the obstacle. A second method of towing maintains the flow line bundle at a constant depth below a surface of the body of water so that the bundle will clear any obstacles on the floor of the body of water. After the flow line bundle is connected between a subsea wellhead and a producing platform located within the body of water, the space between the conduits and the tubular covering member is flooded to sink the flow line bundle to the ocean floor and to provide heat transfer between the conduits and the tubular covering member.