Technical Note FlexSteel Pipe Transport, Installation, and Handling

Transcription

1 Technical Note FlexSteel Pipe Transport, Installation, and Handling Tech Note No. : TN_FlexSteel_113, Rev 0 Date : 20 February 2006 Prepared By : David Lenzer Approved By : Michael Case This technical note presents an overview of the typical packaging, handling, and installation scenarios for Wellstream s FlexSteel spoolable pipeline. 1. Introduction FlexSteel spoolable pipe (FlexSteel) is a durable and cost effective alternative to steel pipelines and other spoolable products. FlexSteel is designed to be installed on the surface, buried below grade, or submerged in compatible fluids to depths within the constraints defined on each pipe datasheet. FlexSteel is spooled onto transportation reels at the factory and typically shipped to the project site on a double drop flatbed trailer. The FlexSteel can be deployed between its connection points using a variety of methods. The most common installation methodologies are discussed herein. Once the pipe is installed, it should be pressure tested to verify it has not been damaged during installation. 2. Packaging FlexSteel pipe is packaged on 12 foot diameter steel reels as shown in Figure 2-1. These reels are approximately 8 wide and weigh up to 9.5 tons fully loaded. The empty reels weigh less than 2 tons. The pipe is spooled on the steel reels with two end fitting connectors already installed on the pipe. The pipe is pressure tested at the factory to verify the integrity of both the pipe and fittings prior to shipment. The spooling of the pipe results in one inboard (wrap closest to drum of reel) and one outboard end fitting that are tied off to the spokes of the reel. The reel and pipe are to be lifted using a spreader beam onto or off of the selected method of transportation (See Figure 2-2). The reel can also be lifted by a fork truck fitted with extended forks or a carpet rod (through center of hub) of sufficient structural integrity (See Figure 2-3 and Figure 2-4). Other means of moving the reels should be reviewed with Wellstream engineering prior to attempting to minimize the potential for damage to the reel, the flexible pipe, other equipment, or personnel. Report No.: TN_FlexSteel_113, Rev 0 Page 1 of 19

2 Figure Diameter Steel Reel Figure 2-2 Lifting with Spreader Beam Report No.: TN_FlexSteel_113, Rev 0 Page 2 of 19

3 Figure 2-3 Lifting with Fork Truck with Carpet Rod Figure 2-4 Lifting with Fork Truck with Extended Forks Report No.: TN_FlexSteel_113, Rev 0 Page 3 of 19

4 3. Transportation For most applications, the FlexSteel pipe will be transported over land by truck or trailer. Wellstream ships FlexSteel by truck to most locations throughout the US and Canada. Typical transportation equipment is shown in Figure 3-1 and Figure 3-2. Figure 3-1 Truck Transport Figure 3-2 Installation Trailer Transport Report No.: TN_FlexSteel_113, Rev 0 Page 4 of 19

5 4. Installation Methods FlexSteel may be installed as part of new construction or for rehabilitation of existing pipelines. It is anticipated that most applications for FlexSteel will include burial of the pipe some distance below grade; however, laying the pipe exposed on the surface is also acceptable as the product is designed for direct sunlight/uv exposure. The duration of this exposure is dependent on the UV stabilization package incorporated in the outer shield so please consult Wellstream for acceptable duration for your specific application. The keys to a successful installation are good communication and careful planning before arrival of the pipe/equipment/personnel. The ability to stage the pipe for proper deployment in the field is essential and is the main goal of the site evaluation that should be performed prior to the initiation of the installation campaign. Upon arrival of FlexSteel to the construction site, there will need to be a crane or specially fitted forklift that can support the 9.5 ton reels on location to unload and position them. As long as the planning is done up front to determine the location and orientation of the reels when offloaded, a crane is typically not necessary on-site during the installation. FlexSteel can be deployed using a number of different methodologies. The most common are from an installation trailer, A-frame structure, or Jack Stands. The reel may be either static as in a pull-in operation or may be driven along the route as the pipe is laid from an installation trailer or Flatbed/A-frame configuration. Some of the least invasive methods of installation include rehabilitation pull-throughs, directional drilling, and plough-in. The equipment and personnel necessary to support the installation is dependent on the specific project. In a typical pull-in scenario with the Wellstream technician and equipment on-site, the only need is for a piece of equipment (with operator) such as a front-end loader, backhoe, or dozer (side boom preferred) to pull the pipe, cradle it into position, and help maneuver installation aids (A-frames, jack stands, swaging machine, etc.). General laborers are beneficial as well (typically one required) to help with the manipulation of the installation aids and monitoring of the pipe route to minimize the potential for installation related damage. Examples of various installation methods are shown in Figure 4-1 through Figure 4-8. Report No.: TN_FlexSteel_113, Rev 0 Page 5 of 19

6 Figure 4-1 Lay Direct from Installation Trailer Figure 4-2 Deploy from Stationary Jack Stands Report No.: TN_FlexSteel_113, Rev 0 Page 6 of 19

7 Figure 4-3 Drag Into Position Figure 4-4 Pipe Layover into Ditch Report No.: TN_FlexSteel_113, Rev 0 Page 7 of 19

8 Figure 4-5 Rehabilitation Pull-Through (3 FlexSteel into 4 Steel) Figure 4-6 Rehabilitation Pull-Through (4 FlexSteel into 6 Steel) Report No.: TN_FlexSteel_113, Rev 0 Page 8 of 19

9 Figure 4-7 Plough-In Figure 4-8 Directional Drilling Report No.: TN_FlexSteel_113, Rev 0 Page 9 of 19

10 5. Installation Considerations and Aids FlexSteel can be installed using methods similar to any rigid or spoolable pipeline product. There are a wide range of installation aids that have been developed by Wellstream, clients, contractors, etc. to help facilitate various types of FlexSteel installations. This section provides a good cross-section of the types of equipment and what they are used for. With each installation scenario, selecting the proper aids is an important part of the planning process. Reel Staging and Positioning When installing from a static location it is important to keep two considerations in mind: Pay-off from the bottom of the reel. Pull at a slight angle away from the inboard end fitting. These are diagramed in Figure 5-1. Paying off from the bottom of the reel helps to reduce the tipping loads on the jack stands or A-frames. This also makes it easier to control the direction of the pipe as it is being deployed. By pulling at a slight angle away from the inboard end fitting, the pipe will naturally pull away from this fitting preventing it from becoming snagged during the deployment process. It is difficult to stop the deployment fast enough to prevent damage to the pipe if it gets caught under this fitting. Careful monitoring and taking precautions to push the pipe away from this region during unspooling will prevent any problems of this type. Understanding this will help decide where to place the reels when they are taken off the truck and what orientation they should be in to facilitate the installation. Figure 5-1 FlexSteel Preferred Reel Positioning and Pay-off Report No.: TN_FlexSteel_113, Rev 0 Page 10 of 19

11 Reel Support Structures Reel support structures must be stable for deployment and strong enough to support the 9.5 ton weight of a fully loaded reel. These structures may or may not include mechanisms for lifting the reels, braking during deployment to prevent free-spooling, and/or re-spooling. The most common types of reel support structures include: Installation Trailers A-Frames/Sleds Jack Stands Installation trailers are the preferred method in that they minimize set up time and provide the safest means of handling the reels and deploying the product. The trailer can be easily relocated to various sites and allows for easy repositioning of the reel. They also allow the option of laying the pipe directly or pulling off from a stationary point. A wide variety of trailers have been developed by both Wellstream and the installation contractors. Some of the trailers are simply A-frames on wheels that can carry and deploy pipe but require a crane to load/unload. Others incorporate a means of lifting the reels into place. The most advanced trailers incorporate a means of lifting the reels and an active braking/re-spooling mechanism. Some of the various FlexSteel installation trailers are shown in Figure 5-2. Figure 5-2 Installation Trailers A-Frames are another very stable means of installing the FlexSteel products. These tend to be continuous frames that the reels are set on. They can be mounted on a truck with Report No.: TN_FlexSteel_113, Rev 0 Page 11 of 19

12 the reels and taken to site allowing the pipe to be deployed directly from the A-frame on the back of the flatbed. Alternatively they can be lifted with the reel and placed in the proper configuration for a later pull-in. The A-Frames can be moved around to the reel locations and loaded on site for installation. Like trailers, some A-frames incorporate lifting and active braking/re-spooling mechanisms. Figure 5-3 shows some of the various A- Frame structures used for deploying FlexSteel on location. Figure 5-3 A-Frames Jack Stands are the most portable of the reel support structures. Relative to trailers and A-Frames, they can be moved easily to new locations. Jack stands require a stable footing and must be used with care as they can tip if overloaded or placed on uneven ground. Jack Stands are shown in Figure 5-4. Regardless of the type of system used, it is important that precautions be taken to assure the support structure remains stable. It is also necessary to assure some means of braking is available to avoid free-spooling of the reel which can lead to excess slack in the pipe and possible cross-over looping that can result in damage when pulled. Braking mechanisms can be built into support structure or as a separate device. As a last resort, two people can maintain tension on the pipe by holding back the reel at the spokes or using a 2x4 as a lever under the rim of the reel. These latter methods do not provide the uniformity of a true braking system and can be hazardous if care is not taken due to the momentum of the reel when turning. Report No.: TN_FlexSteel_113, Rev 0 Page 12 of 19

13 Figure 5-4 Jack Stands Report No.: TN_FlexSteel_113, Rev 0 Page 13 of 19

14 Pull Heads Various pull heads can be used to help pull the pipe into position. The pipe is delivered with shipping heads that have an eye bolt installed providing a limited amount of capacity for maneuvering the pipe into position. In many cases this is all that is necessary. However, in situations where the tension load on the pipe will be significant (more than about 2 tons), or where the load line is not directly in line with the pipe, an installation pull head should be used. These can be as simple as a padeye welded to a blind flange, or can be a full cover designed to protect the flange and end fitting from scrapes and impacts during installation. There are also specialized pull heads designed for pull-through operations where the standard ANSI flange is too large. Examples of some of the pullhead arrangements are shown in Figure 5-5. Figure 5-5 Pull Heads Report No.: TN_FlexSteel_113, Rev 0 Page 14 of 19

15 Choke Straps FlexSteel pipe can also be maneuvered using choke straps. While the loading here cannot be as high as using a pull head as it can damage the pipe if overloaded, it is a useful means of grabbing the pipe to pull into position. These straps can either be applied directly to the pipe or immediately behind the end fitting. When applied behind the end fitting, it is important to make sure that the loading does not result in bending where the pipe and end fitting meet to avoid forming a kink in the pipe that would need to be cut out. For straps directly on the pipe itself, since the polyethylene shield has a low friction coefficient, it is sometimes necessary to use duct tape or equivalent to get the strap to grab. Wellstream recommends a minimum of a 3 wide strap and 3 or more wraps to help distribute the load. Careful monitoring to assure the pipe is not necking down in the area of the strap will help assure no damage to the structure. Various strap configurations are shown in Figure 5-6. Figure 5-6 Choke Straps Report No.: TN_FlexSteel_113, Rev 0 Page 15 of 19

16 Installation Guides During the installation it is beneficial to have guides in place to help with the deployment of the pipe. These are used for making corners, routing around obstacles, etc. In general, the higher the tension load, the more guides are needed. FlexSteel is rated with a minimum bend radius (stated on data sheet and stamped on the pipe) which should not be violated for any reason as it may result in damage to the pipe. Ideally, a guide which meets or exceeds the minimum bend radius is used to assure this is not violated. However, this is usually not practical in the field. In the field, trees, dirt/gravel, vehicles, straps, and snatch blocks are more readily available and can be utilized for this purpose. Examples of various means of guiding the FlexSteel product around corners and obstacles are shown in Figure 5-7. Figure 5-7 FlexSteel installation guides Report No.: TN_FlexSteel_113, Rev 0 Page 16 of 19

17 Rehabilitation FlexSteel is an ideal candidate for pipe rehabilitation due to the ability to provide a quick, full structural repair (See Figure 4-5 and Figure 4-6). The 3 product will fit in a standard 4 steel line and the 4 can be installed in a 6 steel pipe. FlexSteel may also be installed in place of deteriorated pipes of the same or similar size using pipe bursting or pipe splitting techniques. Single pulls of up to 2km, including several sweeps, have been successfully completed. The primary limitation is the length of wire line that can be pushed through the pipeline to pull the FlexSteel into place. Longer pipelines can be installed in several segments with conveniently located bell holes at intervals within the capacity of the wire line equipment. 6. End Terminations FlexSteel pipe is typically shipped with ANSI 600 end fittings attached to each end. The pipe is fully hydro tested in the factory (1.3 x maximum operating pressure) to assure structural integrity. The end fittings are constructed of a grade of 316 stainless steel rated for extreme cold service. The flange is carbon steel and due to the lap flange arrangement is easily rotated to align the bolt holes at a given connection. A 316 stainless steel spiral wound gasket is recommended to assure no leakage problems. The end flange can be cut off to provide a low profile welded connection if desired. Typical end fitting connections are shown in Figure 6-1. Figure 6-1 FlexSteel end fitting configurations The end fittings are attached to the pipe using a double swage process. This process first expands the inside of the fitting (stem) to minimize any internal diametric deviations at the Report No.: TN_FlexSteel_113, Rev 0 Page 17 of 19

18 fitting. The external sleeve (ferrule) is then swaged down to develop the clamping force and fluid seal that ensures performance over the life of the pipeline (See Figure 6-2). End fittings can be installed on location using Wellstream s field swaging unit as shown in Figure 6-3. It is easiest to perform this installation with the swaging machine suspended from straps as this allows the machine to be tilted slightly and maneuvered easily making alignment with the pipe much easier. Swaging Process Interior Swage with Dolly Exterior Swage with Die Figure 6-2 End Fitting Swaging Process Figure 6-3 End Termination with Field Swaging Machine Report No.: TN_FlexSteel_113, Rev 0 Page 18 of 19

19 7. Gas Venting Permeated gasses are a consideration for all polymer piping systems carrying hydrocarbons. The rate of permeation is very small so typically this is not a problem. With single layered poly pipelines these permeated gasses dissipate directly into the atmosphere or ground surrounding the pipe. FlexSteel is a multi-layered product with an annular region between the inner and outer polymer sheaths where the steel reinforcement is. The construction is such that it allows the operator to control where these permeated gasses are transferred to. It is important that a path be provided to avoid pressurization of the wall of the pipe which can cause ballooning of the external sheath or collapse of the internal liner if the line is depressurized rapidly. Wellstream uses a proven technology of venting this internal layer through the end fittings. Jumper hoses at each end fitting connection allow this vent to be conveniently located at any point along the length of the line (Reference Figure 6-1). The gasses can either be re-injected into the gas stream, passed through to the low pressure side of a separator, flared, bottled, or even vented off in a safe manner. Wellstream can provide low pressure vent valves that will allow the gas to vent at a safe pressure directly from the end fitting. 8. Conclusion Wellstream s FlexSteel flexible steel pipe is a cost effective alternative to steel and other spoolable pipelines. It is suitable for a wide range of applications including gas and oil gathering, injection and flowlines, effluent disposal, etc. Installation may be accomplished by any of the methods normally used for installing other pipe products. Simple installation aids make the deployment process easy using readily available equipment. The product is durable, easy to handle, can be installed quickly, and will provide many years of maintenance free service eliminating the need for chemical treatments and cathodic protection systems. The product is suitable for above grade, underwater, and buried applications. All of these features help support why our customers consider FlexSteel the ultimate pipeline solution. Report No.: TN_FlexSteel_113, Rev 0 Page 19 of 19