Flow assurance is a key aspect of offshore, particularly deepwater developments. Tremendous progress during the past two decades in the understanding of the issues and the required technology has enabled the developments be designed and operated with low risk of flow assurance problems. However, the problems have not been eliminated due to system component failures or un-designed for operating conditions. Real time monitoring of the production and transportation system can help significantly reduce the occurrence and impact. The present paper discusses the use of non-intrusive fiber optic technology for this purpose.
A series of fiber optic sensors for temperature, pressure, heat flux, strain, and acoustic measurements have been developed, which form the basis of the methods proposed in this paper for detecting the formation of hydrate plugs in pipelines, for determining the amount and location of paraffin deposition, for pig detection, and slug detection.
As one of the critical issues for deepwater oil and gas developments, flow assurance has progressed over the past two decades from mostly pipe sizing and flow pressure management to an integral part of the development and production process. Tremendous progresses have been made in the understanding of flow assurance issues and in the development of related technology. Operational procedures are commonly developed with flow assurance in mind. These progresses have enabled the deepwater development be designed and operated with low risk of flow assurance problems. Some subsea developments have been operated at almost no unplanned production shutdown.
However, the problems have not been eliminated due to system component failures or un-designed for operating conditions. Real time monitoring of the production and transportation system can help significantly reduce the occurrence and impact. The present paper discusses the use of non-intrusive fiber optic technology for this purpose.
Flow assurance is a cross-functional discipline with technical areas including multiphase flow and pressure management, thermal insulation, slugging issues, gas hydrates, paraffin deposition, asphaltene deposition, scales, erosion and internal corrosion, emulsion, etc. In this paper, we focus on gas hydrates, paraffin deposition, and slugging/liquid management.
As is well known, gas hydrates form under high pressure and low temperature conditions and can plug flow path during normal flow or during start-up. Gas hydrate plugging is a fast paced phenomenon, occurring as quickly as a few hours.
With the exception of a few special cases, for example high pressure or black oil systems, gas hydrate equilibrium can be accurately predicted (with an accuracy of about 2°F). The required amount of thermal dynamic inhibitors can also be reliably predicted with good quality hydrocarbon and formation water samples. These have enabled the determination of the time and location of potential hydrate occurrence in the system, thus making the hydrate prevention designs reliable.
New technologies such as low dosage hydrate inhibitors and active heating systems with heating medium or electricity have been developed and applied to offshore/deepwater developments. These technologies can reduce the hydrate prevention cost, simplify operations, and reduce remediation cost.
