SPE Projects, Facilities & Construction
Volume 5, Number 4, December 2010, pp. 218-224

Summary

Projects progress through phases of design, construction, installation, commissioning, initial startup, and operations. This paper addresses issues that arise at initial startup. Initial startup is defined here as the period when reservoir hydrocarbons are produced for the first time.

Initial startup of a subsea development is one of the most challenging periods in the operational life of the facility. Many issues complicate this period, including

• People issues. Many people from many teams are required to execute a startup; roles and responsibilities may be unclear and will change over the course of the startup; persons-onboard (POB) issues limit the number of people who can participate; personnel involved may not be fully trained in the operation of the facility.
• This will be the first time much or all of the equipment is used in live hydrocarbon service. Design flaws, commissioning omissions, and infant mortalities will reveal themselves.
• Preserving completion integrity requires low rates and slow bean-ups during initial startup because of high formation skin. Chokes designed for high rates and low pressure drops may not be capable of controlling the well at low rates. Also, topside systems designed for peak rates may not function well at low flow rates.
• Low flow rates and low initial temperatures result in hydrate risk, which may challenge the flow-assurance strategy.
• Completion and stimulation fluids returned during the initial well cleanup are corrosive and are difficult to treat. Typically, specialized water-treatment equipment is installed temporarily at topside to treat these fluids. The flowback fluids may also contain solids from the reservoir and from construction debris that may cause problems such as plugging small ports in control valves.
• Drilling, construction, installation, and commissioning activities [simultaneous operations (SIMOPS)] may still be in progress. The exact state of equipment items may be unclear and may change over the course of the startup.
• Reservoir engineers will seek to obtain reservoir information through well tests, especially pressure-buildup tests. Other data-collection efforts are important to validate the design and establish benchmarks.
• Some regulatory requirements apply specifically to the startup period.
• Special procedures are usually written for the initial startup. These will differ in important ways from the normal operating procedures. There is risk that there may be errors in the startup procedures, that operators may err in implementing the procedures, or that equipment designed for normal operation will not function well at the conditions imposed by the startup.
• Startup is one of the most hazardous periods in field life. Effective risk management is essential.

Careful planning is required to achieve a trouble-free startup. This paper describes the key requirements for generating effective initial-startup plans and procedures.

© 2010. Society of Petroleum Engineers

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History

• Original manuscript received: 23 October 2009
• Meeting paper published: 4 October 2009
• Revised manuscript received: 19 March 2010
• Manuscript approved: 17 June 2010
• Published online: 8 December 2010
• Version of record: 9 December 2010