Unpiggable Pipelines

Since the introduction of in-line inspection tools, there have always been pipelines that were considered unpiggable. Typically, it is a combination of various circumstances relating to pipeline design, operating conditions, and/or product properties that prevents a successful in-line inspection using traditional methods.

Colorful ROSEN Toolbox illustration where circles with different topics come together to form a solution.

The ROSEN Toolbox approach for your unique challenging project

We have dedicated an entire diagnostics division to finding ILI solutions to those challenging pipelines. With our global presence we provide tailored solutions, backed by more than 40 years of experience, expertise and comprehensive technology portfolio. 

As each challenge is unique, building a specific tool for each solution is not feasible. Therefore, a flexible approach is needed that can be adapted to each individual case: The ROSEN toolbox approach. It consists of complementing units, such as technologies, methods, and market knowledge, which together enable our Solution Experts to optimally address each challenge. A typical solution package consists of various elements, including:

  • Engineering studies and project management
  • Comprehensive pipeline preparation, cleaning and sediment profiling
  • The most suitable sensor technology, including MFL, UT, EMAT, EC, etc.
  • Specialized tools, including free-swimming, robotic, tethered, etc.
  • All necessary auxiliary equipment, including temporary traps, pumps, etc.
  • Tool tracking and monitoring systems
  • Best-quality data collection under adverse inspection circumstances

The ROSEN Toolbox 

Asset types and their typical challenges

Plant and process pipelines in a refinery with a white and red smokestack.

Pipelines with complex geometries and demanding operating conditions

Facility and process pipelines are used worldwide for efficient and safe product transfer. These pipelines transport crude oil, refined product, natural gas, chemicals, and lubricants, among other products in refineries, terminals, processing plants, etc. Not only do these pipelines often operate in high-consequence areas, they are also within close proximity to other systems. Facility and process pipelines typically travel within a facility or connect different facilities, thereby leaving the controlled area within the fence. The original design plans for these pipelines rarely considered the need for internal inspection.

Facility and process pipelines often present the following challenges:

  • Single or no access
  • Dual-diameter or multi-diameter design
  • Wide rage of wall thickness
  • 1.5D, miter, and back-to-back bends
  • Unknown cleanliness conditions
  • Low or no flow
  • Flow reversal not possible
  • Highly reactive and/or hazardous mediums
Piping system in the middle of autumn trees.

High amount of bends, including back-to-back and diameter changes

These systems often contain several interconnected pipelines with varying diameters, and are generally used to transport gas within the midstream or downstream sector. They often distribute gas at a low pressure to other terminals or industrial facilities, both within and outside of urban areas. The delicate balance between supply and demand of product relies on the efficiency of these assets. In addition, many of these pipelines are within close proximity of densely populated areas.

Although gas pipelines comprise the majority of pipeline networks, they often present unique inspection challenges, including:

  • Dual-diameter or multi-diameter design
  • 1.5D and back-to-back bends
  • Limited to no accessibility
  • Unidirectional operations with low flow and/or pressure
  • Heavy deposits such as black powder
  • Unbarred offtakes
Four pipelines in the middle of a desert.

Multiphase medium and limited to no access points for inspections

Infield, or gathering, pipelines transport fluids or gas from the well area to a point of collection. As fields age, low-pressure operating conditions can present significant challenges. These systems may experience extreme temperatures when transporting single ore multi-phase products. Infield pipelines may carry debris along with a mixture of oil, gas and water. Though many obstacles exist, particularly in low-pressure or low-flow lines, overcoming speed excursions during inspection is one of the main challenges.

Other inspection challenges relating to these assets include:

  • Onshore and offshore environments
  • Single or no access
  • Pipeline designed with no consideration for internal inspection
  • Wide range of wall thickness
  • 1.5D bends
  • Unknown cleanliness conditions
  • Single, low ore unidirectional flow, where reversal is not possible
  • Temperature variations
  • Wide range of operating pressures
Black loading pipeline in the sea to a tanker in the background.

Critical asset for demanding loading and offloading cycles

Tanker loading/unloading lines are unique pipeline assets in the oil and gas industry. In many cases, these pipelines connect shore-based installations to a subsea pipeline end manifold (PLEM). The PLEM is connected to the surface buoy by subsea hoses. The mono-buoy is then connected to the tanker using floating hoses to accomplish the loading or unloading process. As these lines are the point of export and/or import of hydrocarbons, and in most cases there are no alternative means, they are often deemed a critical element in an operator's network.

Loading lines often present the following challenges:

  • Single access
  • Dual-diameter or multi-diameter design
  • Wide range of wall thicknesses
  • 1.5D and miter bends
  • Unidirectional, low or no flow
  • Flow restrictions based on port loading and offloading schedules
  • Unknown cleanliness conditions
  • Coastal environment
  • Unusual pipeline design
Underwater pipelines in the sea, overgrown and swarming with fish.

Ensuring performance and environmental protection in a harsh environment

Pipelines can be submerged as far as thousands of meters below the sea, redefining extreme conditions. Their operation is typically coupled with great environmental risks, high costs, and harsh operating conditions. In addition, they are increasingly finding their way into the public eye. Our Solution Experts are extremely well equipped to cope with subsea pipelines' operating conditions and ensure inspections of the highest standards.

Some of the challenges include:

  • Wide range of wall thicknesses
  • Tight bends and/or mechanical deformation
  • Single or no access for internal inspection systems
  • Unbarred offtakes
  • Low flow and/or unidirectional flow
  • Dual-diameter or multi-diameter design
  • Extremely high-pressure

These assets often transport crude oil, gas, refined or multi-phase products, which are accompanied with their own set of challenges, including heavy debris or sour service. Subsea pipelines are often required to be inspected with minimal disturbance to normal operations.

Solutions for unpiggable pipelines

Our competence is built on more than four decades of company experience in the in-line inspection business. This allows us to not only understand the special requirements of challenging pipelines but also to provide successful in-line inspection and integrity assessment services for unpiggable pipelines.

Gain deeper insights into our expertise