Introducing The Gemini Combo Tool
BJ Services announced the introduction of the Gemini system, a new range of combo tools that provide calliper, metal loss and mapping information in a single tool. In response to customer demand, BJ Services’ pipeline inspection services group embarked on an ambitious campaign to develop and deploy the Gemini combo tools, integrating existing technology and customer benefits found in the current fleet of Geopig and Vectra tools. Unlike conventional combo tools, the Gemini tool uses an active speed control with a gas bypass capability to run in high-speed gas pipelines to obtain both corrosion and deformation information without restricting gas flow or line speed, a feature common to the Vectra magnetic flux leakage (MFL) metal loss tools.
Drawing from personnel at BJ Services’ bases in Calgary, Houston and Pescara, the Gemini tool development team worked to meet the tight four-month deadline. Specialists from various disciplines, including electronics, mechanical and software development, contributed to the initiative. To date, BJ has successfully completed multiple inspections in high-speed gas pipelines with the Gemini tool for TransCanada Pipeline, ANR and Alliance Pipeline in the United States and Canada.
The Gemini tool allows pipeline operators to accurately size and detect corrosion features using the triaxial sensor technology that was first developed by BJ Services for Vectra MFL tools launched in the late 1990s. In addition to accurately sizing and detecting corrosion features, the unique design of the Gemini tool sensors effectively detects cracks in dents and other mechanical damage, including wrinkles, gouging and metal loss within dents. The tool also sizes and detects dents in the pipeline. The high-density calliper sensor spacing and high axial sample rate allows for accurate, effective strain in dent calculations to be performed for dent repair prioritization.
The standard inertial mapping unit on the tool makes it possible to calculate bending strain information, as well as provide accurate pipeline location information, a feature introduced by BJ Services in the 1980s for its industry-leading Geopig calliper tool. This capability can be critical; especially when the pipeline is located in a geotechnical unstable area, such as was the case during an inspection carried out on behalf of a client in California. The pipeline exhibited a potential for increased bending strain as the result of movement. The inertial unit provided accurate location information that was used to determine the pipeline’s centreline and to identify location anomalies.
The Gemini tool development campaign required that a new range of data storage and collection electronics be designed. The new systems can collect more than two terabytes of information about the condition of a pipeline, enabling a much higher sensor density than that of previous technologies. As a result, it provides increased detection and sizing accuracy. The development of the tool included integration of the data analysis with the existing BJ Services GeminiView viewing and analysis software. GeminiView software has been used for many years to analyze and view BJ’s Profile calliper, Geopig high-resolution mapping calliper and Vectra metal loss tools. The data integration has been seamless, allowing correlation of existing Geopig and Vectra system data sets with new Gemini tool data for Run2Run corrosion growth or other comparative analysis.
The 30- and 36-in. Gemini tools have been successfully deployed in the field numerous times. The 24- and 42-in. Gemini tools will be available in the coming months to meet customer and industry needs. Plans are in the works to develop additional sizes to complement the existing tools in the near future. BJ Services will continue to operate the high-resolution Geopig and Vectra tools for those customers who do not require combination technology.