ENVIRONMENTAL ISSUES IN PIPELINE FACILITY ABANDONMENT

Abstract

A condition of offshore production licences in Australia, as in most countries, is that the operator undertakes to remove all facilities including pipelines. Frequently, when decommissioning an offshore facility, the operator will seek to leave the pipelines in place to avoid the costs of removal. In order to obtain approval for in-situ abandonment, however, the operator must satisfy regulatory authorities that the pipelines pose no hazards to the environment or to recognised beneficial uses of the offshore zone. Potential hazards to be considered include mechanical or physical effects of the pipe on the seabed, chemical and water quality effects due both to release of residues of the contents of the pipe and to the degradation of the pipe walls and coatings by mechanical and chemical action, and ecological effects.

In reaching a recommendation in a particular case the above factors must be addressed, and it must be shown with reasonable certainty that recognised beneficial uses will not be disadvantaged. A strategy for reaching this position is outlined.