Abstract

This SAGD development is a tie-back extension to an existing upgrader. Two parallel pipelines ship water and emulsion between the two facilities: water is piped from the upgrader to the SAGD wellpads at 130°C where it is heated through OTSGs before injection into the wells and a water/bitumen emulsion is then retrieved from the wells, to be piped back to the upgrader at 150°C where the bitumen is separated out.

The terrain between the two facilities is difficult with ca. 60% muskeg and several creeks, railroads and highways that require HDDs (Horizontal Direction Drill).

Given the high design temperatures and the mostly non-competent soil, an electrically traced ITP pipe-in-pipe was selected as the most robust solution. The following advantages in operation, construction and for integrity surveillance were identified by the operator:

  • Extremely efficient thermal insulation

  • Unlimited shutdown capability

  • Self-anchoring of the inner pipe to the outer pipe, reducing reliance on soil properties

  • Simple pre-tensioning using the heat-tracing system

  • Reduced thermal expansion, eliminating expansion loops

  • Negative buoyancy, eliminating the need for anchoring the pipeline

  • High integrity of the jacket pipe with

    • Leak before spill detection capability

    • Second-to-none leak detection sensitivity (x1000 relative to volumetric methods)

A key learning of construction during the winter of 2013 was that up to 1 km per day could be built.

The presentation will detail the system key elements, the rationale for its design and provide the lessons learned from the wintertime installation in a typical northern Alberta SAGD development, and in particular how the electrical heat tracing provides schedule control for the pre-tensioning.

The technology has the potential to significantly change the operation of oil/bitumen fields by eliminating the requirement for diluent. The heat tracing technology combined with an extremely efficient insulation allows transport of the hot fluids over unlimited distances.

In the wider picture, the pipe-in-pipe technology provides a means to achieve an extremely sensitive pipeline integrity surveillance with almost instantaneous detection of all but the smallest leaks (which will be detected eventually); it could be proposed as a reliable solution for difficult areas where enhanced scrutiny is deemed necessary, such as wetlands, HDDs, unstable terrain etc., at an installed cost that is not significantly higher than for a simple pipeline.

During the winter of 2012-2013, a first application of an Electrically Heat Traced Flowline (EHTF) based on pipe-in-pipe (PIP) technology was installed in the Fort McMurray area. It consists of two buried high-temperature lines to be operated by a major Canadian Oil&Gas Company at design temperatures of respectively 110°C and 150°C.

This technology has been selected by the operator because of advantages inherent to the technology and the project execution has demonstrated that this novel solution is compatible with the severe weather conditions and areas of northern Alberta. Moreover, careful planning and use of the heat tracing capability of the pipelines provides simple schedule control of the required pre-stressing of the pipelines prior to burial. The technology has the potential to significantly change the operation of oil/bitumen fields by eliminating the requirement for diluent and providing a means of tying satellite developments back to existing facilities. The heat tracing technology combined with an extremely efficient insulation actually allows transport of the hot fluids over unlimited distances.

From an integrity and environmental perspective, the pipe-in-pipe technology provides a means to achieve extremely sensitive pipeline integrity surveillance with almost instantaneous detection of all but the smallest leaks (which will be detected eventually); it could even be proposed as a safety feature on non-thermal pipelines for difficult areas where enhanced scrutiny is deemed necessary, such as wetlands, HDDs, unstable terrain etc., at an installed cost that is not significantly higher than for a simple pipeline.

The articles details the system key elements, the rationale for its design and provide the lessons learned from the wintertime installation in a typical northern Alberta SAGD development, and in particular how the electrical heat tracing provides a simple means of controlling pre-tensioning.

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