Mercury in natural gas: delivering accurate reservoir sampling and analysis

Abstract

Natural gas is a critical part of the world’s energy supply and plays an important role in the transition to lower-carbon energy sources. The industry’s ability to process natural gas safely and efficiently will continue to rely on an accurate understanding of feed gas composition and contaminants, particularly in enabling future developments via existing infrastructure. Mercury is toxic to organisms, highly volatile and produced from hydrocarbon basins globally. Trace mercury concentrations in the hydrocarbon stream can potentially introduce liquid metal embrittlement hazards to industrial equipment, including cryogenic heat exchangers used to refrigerate liquefied natural gas. Inaccurate measurement of mercury levels can lead to adverse impacts measurable across the areas of health, process safety, environment, operations, waste disposal and decommissioning. Worldwide, significant project cost overruns and processing incidents have resulted from the uncertainty of mercury concentrations in hydrocarbon streams. Successful mercury management ideally begins early in a project’s lifecycle with development decisions informed by accurate measurement of mercury concentrations from reservoirs. Historically, this has been problematic, as mercury contamination and scavenging often result in a large range of uncertainty. The results from a multi-company collaborative study to reduce mercury uncertainty with new downhole sampling techniques will be shared in a case study, including production insights from the Julimar Field, west coast of Australia. The recommendations, procedures and operational best practices discussed will be applicable across the industry and beneficial to any party considering the impact of mercury in the development and processing of natural gas resources.