The use of the Electro-Magnetic Acoustical Transducer (EMAT) technology for crack detection by In-Line Inspection (ILI) tools has increased over the last few years. Rigorous validation of the technology leading from the initial application of EMAT inline inspection tools through to determining Probability of Detection (POD) and Identification (POI) has contributed to improved confidence and reliability. EMAT results are being utilized to determine SCC valve section severity, to review and modify hydrostatic test schedules and intervals and could potentially be implemented as a viable alternative to hydrostatic testing. This paper describes the development of an EMAT ILI based program and the related validation process applied by the vendor, pipeline operator and in-ditch personnel. This process is illustrated by demonstrating the performance of the EMAT tool in two 20″ diameter natural gas pipelines which have a documented history of SCC. The tool identified hundreds of features in the two pipelines which were validated both in the ditch and via detailed anomaly sizing.

Aerial leak detection by use of Differential Absorption LIDAR (DIAL) technology has become a viable technique for detecting, quantifying and pinpointing methane emissions from underground pipelines and operating facilities. This paper describes a number of leak detection survey projects performed throughout North America using the DIAL technology from a fixed wing aircraft. The technology was deployed: • In test situations designed to measure the detection capability and lower detection threshold; • In long distance, large diameter, high pressure natural gas transmission pipelines traversing extremely rugged terrain; • In medium pressure pipelines in populated, higher consequence areas. Results from each of the airborne DIAL leakage survey mission scenarios will be described.

TransCanada has a need to manage sections of the pipeline that are susceptible to stress corrosion cracking (SCC) failure by periodically performing hydrostatic testing. Since hydrostatic testing requires a complete service interruption, In Line Inspection technologies (operating in gas pipelines without liquid couplant) are being investigated as an alternate method to managing this hazard. This requirement resulted in a joint technology and tool development project involving GE Energy and TransCanada. The EmatScan® Crack Detection (CD) tool is designed to detect and size longitudinally oriented external SCC features in gas-filled pipelines. During autumn 2002, the EmatScan® CD tool was run in a 64 km section of the TransCanada system. In 2003, field correlation excavations were conducted to assess the accuracy of the tool. This paper describes the results from the correlation program conducted to validate GE Energy’ 36 inch (914 mm) diameter EMAT (Electro Magnetic Acoustic Transducer) crack detection tool.

Maintaining seal oil systems has traditionally been one of the biggest problems faced by operators of centrifugal compression equipment. This problem is compounded when highly toxic gases are being compressed. This paper describes the retrofit of a simple, effective, mechanical dry seal system which eliminated one sour gas operator’s problems. The retrofit resulted in a safe, easy-to-operate system, which vents no toxic gases into the environment. The retrofit was completed on a gas gathering compressor operating with hydrogen sulphide at a discharge pressure of 10,000 kPa (1500 psig), a discharge temperature of 150° C (300° F) and an operating speed of 23 500 rpm. This paper describes the operating problems encountered with the traditional seal oil system, the successful resolution of the problems with the mechanical dry seal system and operational data of the successful retrofit.

Mechanical dry gas seal systems were retrofitted into two centrifugal natural gas compressors which are located offshore in the Norwegian sector of the North Sea. The project was initiated after a fire and several gas explosions had occurred in the gas turbine lube oil reservoir. These incidents were a result of gas leaking from the compressor’s seal oil system and then migrating via the lube oil lines into the reservoir. The dry gas seal systems have eliminated gas leakage into the turbine lube oil reservoir, eliminating the hazard of gas explosion. The retrofits have also provided additional benefits including reductions in space and weight, reduced power usage, reduced maintenance, and elimination of seal oil consumption which had been up to 440 gal./day (2000 liters/day).