Deploying LabVIEW to Monitor Pipelines at the Ormen Lange in the North Sea

Author(s):
Marco Schmid - Schmid Engineering
Harald Månum - Bjørge AS

Industry:
Oil and Gas/ Refining/ Chemicals, Energy/Power

Products:
Embedded Module for Blackfin Processors, LabVIEW

The Challenge:
Developing and installing a long-term monitoring system for a 120 km pipeline off the coast of Norway.

The Solution:
Using a custom, flexible system developed in LabVIEW and deployed with the Schmid Engineering ZMobile™ hardware deployment platform based on the LabVIEW Embedded Module for Blackfin Processors.

The Ormen Lange is the largest natural gas field under development on the Norwegian continental shelf. The pipeline traverses the Storegga rock slide off the coast of Norway, which is one of the longest rock slides to exist on a continental shelf. 

Extreme Conditions Require New Solutions

A massive mound of rubble has accumulated over thousands of years, causing an extremely rough seabed for laying natural gas pipelines. The installation of a real-time vibration monitoring system on the subsea pipeline is required to predict and quickly react to any damage.

The Norwegian high-tech firm of Bjørge AS, which specializes in intelligent underwater instrumentation and condition monitoring, has developed a long-term monitoring system entirely in LabVIEW  for installation at the Ormen Lange.

Schmid Engineering, a Swiss system integrator that offers solutions for mechatronics applications and embedded systems, is deploying this system using the Schmid Engineerig Zbrain™ hardware deployment system.

North Sea Requirements for Subsea Pipeline Monitoring System

The monitoring system must survive extreme sub-sea conditions including strong underwater currents, low visibility, limited power, Gulf Stream currents, water turbulence due to the uneven seabed, and changes in internal pipeline flow.

In addition to these extreme conditions, the project required a tight development timeline to meet production targets, a very low power off-the-shelf hardware deployment platform, and a highly reliable system with built-in logging capabilities.

Meeting Development Timelines with LabVIEW C-code Generation

With the LabVIEW Embedded Module for Blackfin Processors, one engineer was able to reduce development time by generating more than 50,000 lines of C code from the LabVIEW graphical environment in less than 12 months.

The graphical code and generated C code consisted of eight asynchronous threads, four of which required inter-thread communication. Based on Bjørgesurveys, 77 percent of respondents stated that an average embedded programmer can produce 1000 lines or fewer of debugged C code per month. With intuitive LabVIEW graphical programming, this engineer was able to produce more than 4-6 times the code predicted by this rule of thumb.

Deploying to Off-the-Shelf Embedded Hardware

Bjørge was able to deliver a software solution on schedule by combining LabVIEW software with an embedded Analog Devices Inc. (ADI) Blackfin digital signal processing (DSP) chip.

Using graphical programming techniques and the software tools in the LabVIEW Embedded Module for Blackfin Processors, Bjørge-NAXYScreated an application that compiles C code and targets off-the-shelf, embedded ADSP-533 Blackfin Processors from ADI. We combined this technology with the embedded expertise of Schmid Engineering, which built the ZMobile OEM core module, based on the ADI Blackfin processor, with built-in integrated nonvolatile and removable memory, power management tools and analog, digital and communications I/O.

Reliable Low Power Consumption Battery Operated System with Built-in Logging

It is a direct requirement from the government to monitor pipeline vibrations.

To record vibrations in all three axis directions, synchronized measuring points called clamp sensor packages (CSPs) are attached to the pipeline at regular intervals. An inertial master sensor package (MSP) installed on the seabed controls the CSP. This MSP also records water currents, salinity, temperature and pressure for complete characteristics. The links between CSP and MSP units are wireless through acoustic modems. The monitoring system offers three basic modes of operation.  

1. Long term data logging: The MSP wakes up at a configurable time interval, typically every three hours. At first, it measures the distance to each CSP for compensation purpose. Then, the MSP initiates distributed analog data recording at 10 to 20 Hz for 10 to 30 minutes by sending a group call to all CSP nodes. Next, the MSP starts reading water current, salinity temperature and pressure through serial interfaces. When logging has finished, the MSP processes the data and stores it to removable memory. After programming the next wakeup, the MSP and CSPs go to sleep and the whole process repeates. 
2. Event monitoring: In parallel with data monitoring, the lowest power, intelligent mixed signal circuitry continuously monitors all vibrations and water current levels for limiting values. If any CSP detects a high acceleration while asleep, it wakes up and sends a signal to the MSP to initiate the logging scheme.  Likewise, the MSP will wake up and initiate logging if a high water current level is detected while asleep. 
3. ROV rendezvous: A remote operated underwater vehicle (ROV) installs and maintains the monitoring system. Through acoustic communication with an ROV or a top side modem, engineers can change all vital parameters at run time, as well as upload sampled data or Fourier analyzed data for a requested time period. An ROV is able to request data from either a CSP or an MSP at any time and in parallel to its current mode of operation. This reliable communication interface is a key feature of the embedded hardware and software.

Built-in Redundancy

Redundancy is a big challenge in this system. Every action is monitored. In the event of an error, a node performs a self correction and informs its caller about the situation. All nodes communicate to decide if the error is within the node itself or any other nodes. If the real MSP fails, any CSP can become the new MSP to sustain the operation. The pipeline monitoring system has a lifetime of several years, and will be submerged for at least six months at a time; thus, the highest demands are placed on hardware and software reliability, in-program error handling and efficient energy management.

With the rugged conditions and size of the Ormen Lange natural gas field, tight timelines and innovative approaches were required to solve a variety of engineering challenges. Bjørge was able reuse off-the-shelf hardware based on ADI Blackfin Processors and apply graphical programming to generate the code required for deployment. With the LabVIEW Embedded Module for Blackfin Processors, our engineer generated more than 50,000 lines of C code from the LabVIEW graphical environment in less than 12 months.

Author Information:
For more information on this Case Study, contact:
Marco Schmid
Schmid Engineering
marco@schmid-engineering.ch

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