HANDLING OF HYDROGEN SULFIDE AND MERCAPTANS IN OILFIELD PRODUCTION – A MATTER OF ECONOMICS

摘要

For the exploitation of oil and gas fields, operators face many challenges in the production, processing and handling of hydrocarbon resources to deliver products to markets within specifications in a safe, compliant, reliable and competitive manner. Associated gas from mature oilfields subject to enhanced oil recovery methods may contain high concentrations of acid gases such as H2S, mercaptans and organic sulfur species, and CO2. Treatment of the sour gases may add significant operational complexity and cost burden to the already marginal oilfield operations. The whole sustainability of the oilfield operations may depend on the ability to handle the gas and not necessarily the oil. In these applications, selection of a cost-effective solution to handle the sour gases is not a straightforward exercise. Multiple factors must be considered in the selection criteria: financial metrics; safety, environmental and regulatory requirements; capital expenditure; operational cost, reliability, operations complexity; technical requirements; potential impact to public, etc. Proposed solutions may be sensitive to changes in the operating envelope, therefore selected concept should be tested against reservoir performance uncertainties to develop risk mitigation strategies. This paper shares experiences with different producers and offers a decision framework to select competitive solutions for handling sour gas containing CO2, H2S and organic sulfur compounds, considering all potential uses for the associated gas. A comprehensive methodology was developed for conducting feasibility and conceptual studies to add acid gas treatment and handling capabilities to new or existing production facilities that are robust to technical or commercial risks and uncertainties.