July 2018, Vol. 245, No. 7
Features
Getting into the Pig Launcher Groove
By Adam Bozick, Regional Manager, Victaulic
Pipeline pigging is an important part of ensuring reliable pipelines and, when done as part of a larger maintenance program, can significantly reduce the risk of line failure and downtime. Clearing buildup or blockages from gas hydrates, asphaltenes, iron oxides, scale or paraffin is just one way in which pigging helps manage line integrity. Pigging is also routinely used to identify damage from corrosion before it becomes a major issue.
This process, however, can be costly and time consuming with traditional pigging equipment.
Necessity of Pigging
In hydraulic fracturing operations, a site may have low elevation areas in the gathering system where liquids, chlorides, old chemicals or proppants can accumulate. Slugging from this can cause particular challenges for pigging, restricting flow in the pipeline and slowing production.
To avoid these issues, operators may utilize lay flat hose, which offer advantages in transport and storage volumes along with ease of handling. These hoses, however, can still present issues like ice and debris clogging them.
Any line, traditional or lay flat, that is not pigged frequently can become a danger. To avoid unplanned downtime for costly repairs, inline inspection should be planned and performed to ensure line integrity. Routine pigging is just one part of this, but helps ensure that lines are clear and leak-free. In some projects, lines may need to be pigged frequently. In those cases, and in remote areas that are difficult to get pigging equipment to and from, installing multiple pig launchers in the system may be helpful.
When Pigs Y
Traditional pig launchers for lay flat hoses in the field include a “farmer fitting” (flanged Y lateral) and various flanged valves. An 8-inch version of this system weighs somewhere in the neighborhood of 730 pounds. Go up another 2-inch for a 10-inch system, and that weight goes up to over 1,100 pounds. In the field, we know that weight (and space) equal money. Even getting this hefty equipment onsite can be a challenge; it requires additional coordination and cooperation with on-site and off-site crews, and they must wait for the appropriate weather conditions before shipping the equipment. The challenges don’t stop at logistical issues, either.
On the operations side, we know that flanged valves can be difficult and time consuming to install. They can also make maintenance of the pig launchers more difficult, as flanged valves are more difficult to disassemble and require a special tool. Cycling these valves a few times each week also wears away at the valve seat, incurring additional maintenance costs to maintain the valves.
It can be difficult, also, to source parts for pig launchers in remote locations. In a desperate attempt to get back online, operators may unknowingly source parts from a local supplier that is not CWS listed or that does not pickle and passivate their welds to prevent oxidation. This opens operators to any number of risks if the valves, fittings or pig launcher fail from not being welded to the minimum pressure code.
So, What Do We Do?
By simply replacing the bulky flanged connections of the traditional pig launcher system with grooved assemblies, operators can significantly reduce the weight of their pig launcher systems. The same 8-inch system is reduced to about 350 pounds, while the 10-inch system comes in at 575 pounds. For a site that needs ten pig launchers, this means a savings of over 3,800 pounds (or 5,250 pounds for the 10-inch version).
This weight reduction makes transporting the equipment easier and directly translates into fuel savings for the operator.
Pig launchers with grooves instead of flanges are much easier to operate. The enormous force that is required to open a flanged valve is eliminated by the better breakaway torque of grooved valves. The built-in “snipe” (a sort of cheater bar) makes it much easier to open and close these valves. The two bolts on a grooved system are removed with a simple impact gun.
When not in use, the grooved couplings can be used in other areas of the site – for example, when connecting pumps, valves and fittings to lay flat hoses during everyday operations. Of course, this simple assembly and disassembly makes pig launcher maintenance in grooved systems much easier as well, and reduces safety concerns.
Case Study
An operator in northern Alberta and British Columbia used a 10-inch, grooved pig launcher for a year. The older flanged system they had been using took two hours to install, per pig launcher. The new grooved system took only 10 minutes. Because of the flexibility and simplicity of the system, crews were able to utilize the same components from the pig launcher for lay flat assemblies and pump bypasses when the launcher wasn’t in use.
These grooved valves could be operated with much less torque and for longer periods between maintenance than the traditional flanged valves. When routine maintenance was needed, the crews could quickly get the system back online due to how easy the grooved system was to repair in the field.
The ease of operability, functionality and flexibility have led to the operator’s decision to use the grooved pig launcher assemblies at other sites.
Doing Things Differently
Operators are pushing, daily, to reduce their costs in a market where oil prices can vary widely. Without compromising safety, streamlined operations are a premium, which is encouraging operators and builders to improve asset efficiencies and invest in technologies with a higher ROI than what the status quo would provide. To do things better, we need to do things more efficiently – and that means doing things differently.
For the requisite pig launching systems of many operations, this may mean utilizing grooved assemblies instead of the traditional flanged designs that, while they still get the job done, do not offer the biggest bang-for-your-buck. Design changes that can disrupt that status quo are taking root, allowing engineers to look at problems from a different point-of-view to solve challenges more efficiently. P&GJ
Author:
Adam Bozick is a regional manager with Victaulic, a manufacturer of mechanical pipe joining and fire protection systems, where he works with customers in the upstream and downstream markets. He is a member of both the Construction Industry Institute and Rice’s Engineering & Construction Forum.
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