Jorge Garduno

OTC-26007-MS Top of Line Corrosion: An Evaluation of Critical Parameters that Drive Mitigation Methods and System Design in Deepwater Gas Systems

Top of Line Corrosion (TOLC) occurs in deepwater wet gas systems when water vapor condenses on the upper internal walls of the flowline due to the heat exchange occurring between the hot fluid and the colder environment. The condensed liquid becomes enriched by the corrosive species naturally present in the gas stream and assumes a low pH because it does not contain any buffering species such as bicarbonate or iron. The predominant concern is carbon dioxide (CO2), which reacts with water to form carbonic acid (H2CO3), although hydrogen sulfide (H2S) and organic acids can also present significant challenges and drive the corrosion process.

SPE-170824-MS Standard Operating Procedures (SOPs) as a Catalyst for Culture Change

Standard Operating Procedures (SOPs) for oil and gas production facilities are typically written by teams of subject matter experts including at least process engineers and experienced operators.  The team is tasked with identifying the most effective ways to operate the facility (based on safety, environmental protection and economic measures).  Operating the facility consistently in accordance with the SOPs should yield considerable benefits.

Yet, despite their obvious importance, often relatively little effort goes into SOP development and use.

SOPs are frequently developed late in the project, after the design is completed and construction is well underway.  They may be used for little other than operator training.  Following the initial facility startup, they may even end up on a shelf collecting dust.  In this environment SOPs have little influence on either the design or the operation of the facility. 

SPE 123790 - Planning and Procedures for the Initial Startup of Subsea Production Systems

2010 Summary, H.J. Duhon, J.L. Garduno, and N.A. Robinson, GATE

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.

Source: SPE Projects, Facilities & Construction, Volume 5, Number 4, December  2010

Copyright 2010. Society of Petroleum Engineers

SPE 123790 - Planning and Procedures for the Initial Startup of Subsea Production Systems

2009 Abstract, H.J. Duhon, J.L. Garduno, and N.A. Robinson, GATE, LLC

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.  These include:

  • People issues: a great 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 on board (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 rear their heads.
  • 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, topsides systems designed for peak rates may not function well at low flowrates.
  • Low flowrates 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.  Specialized water treatment equipment is typically installed temporarily on topsides to treat these fluids.

Source: SPE Annual Technical Conference and Exhibition, 4-7 October 2009, New Orleans, Louisiana

Copyright 2009. Society of Petroleum Engineers