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SCARPATM (Sand Conveying And Removal apPAratus) is a technology designed to remove sand and other solids from a production separator on either a continuous or batch basis. The system is modular in design which implies that it can be retrofitted into existing separators as well as being incorporated into new builds. The SCARPA™ system can convert a three phase separator into a true four phase separator or a two phase separator into a true three phase separator. The system has been developed for both topsides and subsea production separators.
Conventional methods of removing solids from production separators often involve:
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Allowing the solids to settle in the separator and remove manually during periodic shutdowns |
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Allowing the solids to settle in the separator and batch jet using conventional nozzle based jetting systems |
Conventional sand jetting systems are batch operated and comprise of a series of nozzles providing violent, localised agitation of settled solids to allow removal through drain points in the bottom of the vessel. These systems can cause the following problems:
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Re-mixing - of the oil and water phases as well as wide dispersal of the sand, leading to greatly reduced separator performance and significant sand carryover. |
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Erosion - where high velocity jets impact the separator wall. |
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Reliability - for an intermittently operating system dealing with a highly variable solids concentration. The periodic nature of the jetting means that sand progressively builds up within the separator, reducing the effective volume of the water pad, allowing time for deposits to consolidate resulting in possible corrosion and fluidisation problems. |
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High Discharge Sand Concentrations – which can have a major impact on the downstream receiving systems. Initial peak sand concentrations in the early stages of a sand jetting operation can be as high as 70%wt. High sand concentrations can cause blockage and sand carry over and are to be avoided to ensure a robust and reliable sand management solution. |
 Click image to enlarge |
The SCARPA™ system is a continuously or batch operating sand transport and removal system creating a low velocity flow which runs along the bottom of the separator through the use of specialised eductors.
Eductors are an established solids conveying device that use a small flow of high pressure motive fluid to “pump” a much higher flow, lower pressure fluid. Their suction from behind/ discharge in front format means that they can be hydraulically balanced to generate a dynamic layer of water of comparatively low velocity along the bottom of a separator. This prevents sand from settling and acts as an effective solids transport system with minimal vertical disturbance.
This “hydraulic conveyor belt” can be directed towards one or more discharge outlet nozzles in the bottom of the separator which themselves incorporate eductors, providing controlled ejection of the solids from the separator. Where fine solids are encountered, a SANDSHIELD louvered profiled baffle can be incorporated above the SCARPA™ eductors in the downstream section of the vessel to provide extra solids carryover protection.
The SCARPA™ system will maximise seperation and minimize downtime, offering the following benefits:
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Lower pumped flowrate requirement as fluid within the separator is used as the jetting fluid due to the use of SCARPA™ eductors. |
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No impact on the separator oil / water separation performance |
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Maximise separator water pad residence time as sand is not allowed to build-up when in continuous operation mode |
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No sand carry over to water and oil outlet streams |
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Reduced potential erosion and corrosion of separator |
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Sand is easier to remove as it has less time to “cement” in place. It takes considerably more “flux” to fluidise sand than to maintain its fluidity once fluidised. The “cementing” of oil wet sand over time only serves to exacerbate this problem. |
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Minimises and controls sand concentrations in outlet pipework which optimises the availability and performance of downstream sand handling equipment. Cyclone based receiving systems often experience solids carry over if the inlet solids concentration is above ~5%wt. |
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Limits the size and complexity of the downstream receiving equipment. |
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In the event of an unplanned process shutdown, high solids concentrations in any part of the process are to be avoided. |
In either continuous or batch mode, the SCARPA™ system needs less water, is much less disruptive of the oil/water separation process and removes solids more efficiently than a conventional jetting operation. Typically a longer flushing period is required in batch mode but sand removal operations are generally not time critical. Irrespective of the amount of sand in the separator, the SCARPA™ will not allow the discharged sand concentration to rise above a preset peak thus trading operation time for higher availability and reliability.
The patented SCARPA™ system represents the outcome of extensive research in this area by Cyclotech, including tests with transparent model separators.
Please contact us if:
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You are proposing to install a sand jetting system |
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Your sand jetting system is causing process upsets within the separator |
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You are having problems with your sand jetting receiving system |
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You wish to stop manually removing sand from your production separator on a regular basis. |
