INTRODUCTION
The tools used for the In-Line Inspection of pipelines have changed dramatically in the last few years. These changes have not resulted from fundamental changes in the inspection technologies but rather from the evolution in data processing and storage systems. We can expect that this technological evolution will continue and will pave the way to even more advanced inspection equipment. This paper stresses the cooperative relationships being developed between the pipeline industry and the inspection community and shows how this cooperation is leading to successful research programs. Several of these programs are reviewed and speculations are made on & future development.
Pipeline inspection tools have changed. Inspection service companies have been telling the pipeline operators of the dramatic improvements in in-line inspection tools that have been made in the last few years. All of the service companies now operate what is commonly referred to as high resolution inspection tools. In this paper we will see where we are with current technology and describe briefly, the technological evolution that allowed us to get here. More importantly, we will look at some of the industry sponsored research currently underway that will guide tool development into the future. We will speculate on equipment and technology choices that may be available five or ten years from now.
CURRENT STATUS
Ten years ago, most of the equipment used for the in-line inspection of pipelines (pigs) used analog recorders to process and store information. These recorders were state of the art but were also severely limited in the channel capacity available for sensor information.
In 1986, IBM introduced the second generation personal computer, the IBM AT. This computer used an INTEL 80286 microprocessor running at 8 MHz. It had disk drives with a capacity up to 1.2 megabytes and hard drives up to 40 megabytes. Ten years later, in 1996, personal computers use INTEL 80686 microprocessors running at 300 MHz. They have 128 megabytes of random access memory and 4-9 gigabyte hard drives [I]. This digital evolution has also occurred in signal processing systems. We now have Digital Signal Processing (DSP) technology that is fast enough to capture digital information from literally hundreds of channels of input. Mass storage devices for data acquisition have also evolved to allow the capture of tens of gigabytes of data. It is this technological evolution which has changed the inspection equipment to that which we see today.
The most common inspection technique used for the inspection of pipelines is Magnetic Flux Leakage (MFL) [2-51. Even in the high resolution inspection equipment this is the most common technology. This is the same technology (MFL) that has been used since the 1960?s. The fundamental operating principles have not changed. The real difference between the current tools and the conventional tools is primarily related to the channel density available. We can now collect more information. The magnetic systems have, of course, been improved and sensor technology has evolved. But only because of the processing revolution can we take advantage of these new developments. This technological evolution will continue to spur development and let us take inspection equipment to the next level.
