Abstract

Hydrates have been a constant threat to subsea deepwater operations since pipelines were first used to transport multiphase fluids. Hydrate blockages in pipelines and processing equipment can cause deferment of production and as a result can cause millions of dollars in losses.

The extensiveness and complexities of subsea production systems and deepwater developments such as West Delta Deep Marine (WDDM) in Egypt pose huge challenges in implementing hydrate management strategies. In the past, unplanned strategies were implemented in WDDM due to a lack of Flow Assurance (FA) awareness and understanding, resulting in production deferment caused by hydrate formation or blockages. Operational Expenditures (OPEX) on hydrate inhibitors such as Mono Ethylene Glycol (MEG) and Methanol (MeOH) have been increasing significantly.

Since the implementation of Flow Assurance in WDDM, work has focused on key areas of the development that were hydrate prone, by making use of in-house software and industry good practice. A holistic view of WDDM including equipment and instrumentation was taken, along with the chemistry behind why hydrates form.

To minimise the deferment to production, hydrate monitoring, previously based on a single pressure reading in the flowline, was challenged and changed to the current technique which is based on flowline pressure drop across multiple elements such as flowline, infield line and valves. This has been made possible by implementing a monitoring system based on Pi linked to the control room, allowing engineers throughout the organisation to review a wide range of actual data in real time. As a result of continuous monitoring and optimisation, hydrates are no longer seen as a threat to WDDM production.

Various achievements and lessons learnt in managing hydrates in WDDM over the past 12 years, specifically in hydrate prevention, monitoring, and remediation plan has been compiled. As a result, a "WDDM Hydrate Management Strategy" has been introduced for the operation and future development of WDDM. This paper will share the significant lessons accumulated in WDDM from actual experience of operating the field.

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