Consumers Energy, which is the largest natural gas utility in the state of Michigan and fifth largest in the United States, operates thirteen natural gas storage fields in the state as part of its Gas Transmission and Storage system. These storage fields consist of a network of storage wells connected via a series of short pipeline laterals and headers. Typical field configuration consists of one or two main headers with several laterals branching off to the gas storage wells. Due to the shorter line lengths (2.5 miles or less) and other operational conflicts, it is difficult to utilize conventional online smart pigging methods to assess the integrity of these laterals and headers. Based on the type (welded steel), average age, and operating conditions of the pipelines in these storage fields, an internal inspection method was desired. Consumers Energy has teamed with Baker Atlas to utilize their Vertiline wire conveyed MFL (magnetic flux leakage) smart tools to assess the integrity of these gas storage field headers and laterals. The Vertiline technology was originally conceived for down hole well casing integrity analysis, however, the application was found to be ideal for short section, limited access, and otherwise unpiggable pipelines. The Baker Vertiline technology can currently be used on pipeline sizes up to 24” in diameter, and larger diameter tools are under development. This paper will explore the process that Consumers Energy undertook to utilize wire conveyed MFL smart tools in its gas storage field pipelines. Field preparation for tool runs, running the tool and gathering data, and data presentation will all be reviewed. The advantages and disadvantages, techniques, capabilities, and technology of the wire conveyed MFL smart tools themselves will also be discussed, along with other potential applications such as use in analysis of pipeline river crossings, pipelines lacking pig launching facilities, and offshore production lines.
Investigation properties of high frequency welded steel pipes for natural gas transportation made of X60 steel