Emergence of Flow Assurance as a Technical Discipline Specific to Deepwater: Technical Challenges and Integration into Subsea Systems Engineering

Abstract

Abstract Flow assurance has emerged as a technical specialty, vital to the success of all deep water oil and gas developments. In recent years, significant growth of technical competence in flow assurance has been realized in the oil and gas industry, due to a broad recognition of the technical challenges specific to the operating environments of deep water. Strategies and methodologies have been developed to address solids control and management (e.g., hydrates, wax, asphaltenes, scale). New capabilities and tools have been developed to model and analyze the steady-state and transient thermal-hydraulic performance of systems in multiphase flow, in order to provide the key inputs into flowline sizing, insulation selection, and other elements of system design. Flow assurance has been recognized by many operators as a critical technical activity, present in all the phases of planning, project execution, operation, and production surveillance of deep water developments. Flow assurance analyses originate during exploration activities and continue throughout the entire life cycle of the hydrocarbon exploitation. In recognition of its systems impact, flow assurance has been integrated into a broad scope of the subsea systems engineering process. While the new developments in deep water progress into more challenging operating environments, flow assurance strives to deliver solutions needed for success. These new challenges inlcude cold-earth start-up with high water cuts, increased hydrate risks due to the hydrostratic pressure in the ultra-deep water flowline risers, management of asphaltenes, and long offset subsea developments (25 km and greater). These coupled with the ever increasing demand for highly reliable and cost effective solutions require innovative progression of flow assurance strategies. Competency in flow assurance is critical to companies that get involved in oil and gas development in deep water. Current and future developments in deep water challenge the industry to progress flow assurance technologies to enable successful and profitable development of an ever increasing portfolio of oil and gas accumulations in both deepwater and ultra-deep water around the world. Introduction Flow assurance is a structured engineering analysis process that utilizes the in-depth knowledge of fluid properties and thermal-hydraulic analysis of the system to develop strategies for control of solids such as hydrates, wax, asphaltenes, and scale. The flow assurance process, including its scope and the factors that drove its development are presented in this paper. The emergence of flow assurance as a discipline has been driven by the combination of the hostile environment, challenging fluid properties, and system reliability targets found in deep-water oil and gas production systems. The link between flow assurance and subsea systems engineering is discussed in detail. Flow assurance strategies typically involve a combination of equipment design/selection, operational methodologies, and chemical treatments. As a result, flow assurance becomes an integral part of the subsea systems engineering work-process, and must be integrated with the relevant elements of the asset-development cycle, such as concept selection, subsea project execution, asset operations and subsea system surveillance. To close this paper, a number of the new challenges, such as ultra-deep water developments, that will drive even further progression of flow assurance in the future, are reviewed.