How Reliability for SAGD in Alberta Can Be Improved—And Lessons for Other Remote Operations
by Thomas Webster, on Thu, May 20, 2021 @ 14:05 PM
Steam-Assisted Gravity Drainage (SAGD) is an enhanced oil recovery (EOR) technology that utilizes a pair of stacked horizontal wells to recover bitumen from oil sands. Hot steam is produced in a boiler and injected into the top well, heating the bitumen, reducing its viscosity, and allowing it to separate from sand. The bitumen and condensed steam emulsion drain into the lower well to be pumped up and piped to an upgrader facility.
SAGD involves inherently inclement conditions that can lead to equipment failure due to the nature of the recovery process. High-quality materials of construction are important, as steam is injected at a high pressure into the well at a temperature of 300-340°C (572-644°F).
Rotating equipment reliability is essential in any oil and gas facility. It becomes especially important in remote operations, particularly those that experience cold weather, such as SAGD in Central and Northern Alberta. For such operations, appropriate measures should be taken to avoid failures, which can result in downtime and streamline any testing or maintenance procedures.
Improving Reliability for SAGD in Alberta
Downtime is a massive challenge for remote oil and gas operations. Even with the best maintenance plan, downtime happens. It is not realistic to eliminate downtime, but it is realistic to greatly reduce it with the right seal flush systems and proper planning. SAGD in Central and Northern Alberta relies heavily on rotating equipment, such as emulsion well pad pumps, water treatment pumps, boiler feed pumps, or transportation pumps.
Reliable seal support systems should be used to prolong seal life and prevent failure for such equipment. When operating in remote locations that experience challenging weather conditions, action should be taken to 1) streamline the maintenance procedures, 2) minimize mechanical failures, and 3) winterize equipment.
When challenging weather is at play, checks and maintenance may need to be performed on a more frequent basis to ensure equipment functionality. Thus, having a simple and clear-cut maintenance plan for rotating equipment and associated support systems is key to minimizing the time required for each planned or unplanned maintenance procedure and minimizing safety risks for maintenance personnel.
Easily accessible readable instrumentation for seal support systems can reduce the risk of operator error, speed up any upkeep required, and ultimately reduce unplanned downtime. Downtime can also be reduced through the implementation of systems that avoid disruptions by allowing instrument calibration, troubleshooting, and component replacement to be performed without halting operations.
Minimizing Mechanical Failures
As a general rule of thumb for SAGD, infrastructure components should be high-quality and corrosion-resistant. Therefore, proper material selection is important for SAGD equipment protection to prevent or slow corrosion. Depending on your application, materials include carbon steel, high-temp carbon steel (ZSML), monel, and stainless steel. Materials such as carbon steel and monel are often used in place of stainless steel as a result of the chlorides. As for other SAGD infrastructure, appropriate materials need to be utilized to prevent or slow the progression of:
- Erosion and erosion-corrosion from the presence of solids
- Flow-accelerated corrosion from high fluid velocities
- Localized corrosion from acidic gases and condensed water
Two critical failure points in SAGD are pumps and boiler components. Mechanical seals for pumps rely on support systems to provide lubrication to seal faces, control the pressure and temperature in the seal chamber, flush contaminants or buildup, and prevent leakage. However, seal support systems can be another potential leak point. Threaded connections should be avoided, and the number of connections should be limited as much as possible to reduce the chance of a leak arising.
Clean water is critical to efficient and reliable boiler operations. Higher quality steam results in a higher recovery factor and lower steam-oil ratio (SOR). As around 90% of SAGD water is treated and reused in the boiler, it is necessary to regularly test the treated water. If the water is not properly treated, solid plating can occur on boiler tubes leading to increased operating temperatures which may cause mechanical failure. Hence, a reliable sampling system that provides representative samples should be used.
With an average low temperature during January of -26°C (-14°F), winterization of equipment in Central and Northern Alberta is crucial for equipment reliability. Winterization can involve safeguarding piping, clearing steam lines of buildup, constructing shelters for frequently maintained equipment, and using heating boxes for instruments.
Freezing of water or gas in a pipe causes extreme pressure within the pipe and may cause it to burst. Consequently, pipes may be wrapped in suitable insulation materials such as fiberglass, vermiculate, phenolic or elastomeric foam to protect the pipe. These materials can handle temperatures as low as -30°C (-22°F). Alternatively, heat-tracing systems may be used to control the temperature along a pipe to prevent freezing.
Rely on Local Experts to Help Improve Reliability
Improving reliability for remote oil and gas operations in Central and Northern Alberta can be challenging, as there are many considerations at play. Whether you are looking to improve reliability for SAGD operations or other remote oil and gas operations, local vendors with deep expertise and experience increasing reliability in oil and gas operations should be consulted.
Proper selection of a seal support system may be one of the most important factors for reliable rotating equipment. If you are unsure if you have the right seal support system, it might be time to take a second look.
Edmonton Valve & Fitting is knowledgeable on the requirements to maintain seal support system reliability in the challenging Canadian climate and provides local Field Advisors who can help you ensure you have the right seal support system and recommend solutions to improve reliability.