1. Field of the Invention
The present invention relates to an insulated conduit for transporting fluids which conduit has a negative buoyancy when positioned in a liquid. More particularly, the invention relates to a method of making such a conduit which will sink to the bottom of a body of water.
2. Description of the Prior Art
In many instances, it is desirable to insulate conduits so that the temperature drop of fluids flowing through the conduit is held to a minimum. Conduits carrying fluids from gas condensate wells are an example. Gas condensate as it is produced from a well is at a relatively high temperature. If the temperature drops considerably in the conduit used to transport the gas condensate from the well to a point of further use, additional liquid can condense and cause blockage of the flow line. In other instances, oil is produced from a well at a relatively high temperature at which it has a low viscosity and is easy to transport through conduits. However, if the temperature drop of the oil passing through the conduit is great, the oil can become viscous and difficult to move. The oil may also contain paraffinic constituents which can come out of solution if the temperature drops, adhere to the conduit walls, and cause plugging of the conduit. In other instances, it is desired to transport a fluid from one point to another point and deliver the fluid as near as possible at its temperature at the point of origin. Therefore, there are many instances in which it is desirable to insulate conduits used in transporting fluids.
Oftentimes conduits are submerged in a liquid. For example, oil and gas gathering conduits from offshore wells are located beneath the surface of water. Insulation material is characteristically of the surface of water. Insulation material is characteristically of low density. If an adequate amount of insulation material is positioned around the conduit, the insulated conduit may become buoyant and tend to float in the liquid which surrounds it. This buoyancy can be onerous if it is desirable that the conduit be positioned beneath the surface of the liquid through which it passes, such as along the bottom of a body of water.
It is an object of this invention to provide a process for constructing an insulated negative buoyancy conduit. It is a further object to provide such a process which may be easily carried out using known materials of construction. It is a still further object to provide a process for constructing such a conduit having a water resistant insulation. It is another object to provide a process for constructing such a conduit which has a first structure to prevent heat loss and an additional structure which protects the first structure from the surrounding liquid media. Other objects, advantages, and features will become apparent from a consideration of the following discussion and appended claims.