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Sand-Vac and Well-Vac Well Cleanout Systems

Remove solids and liquids from ultra-low-pressure wellbores

Remove solids and liquids

The Baker Hughes Sand-Vac™ and Well-Vac™ systems use concentric coiled tubing (CCT) combined with a proprietary downhole switchable jet pump to remove solids and liquids from ultra-low-pressure wellbores that are not treatable with standard circulating methods. These cleanout systems isolate the fluids from the reservoir and allow continuous returns without the use of nitrogen. This is particularly advantageous for cleanout operations that require significant amounts of nitrogen or have issues related to supply, logistics, or platform deck space.

Used in extended-length producing intervals, these systems handle crossflow or thiefzone challenges that hamper conventional circulation cleanouts. The tools also incorporate optional built-in pressure and temperature memory gauges to collect accurate downhole data.

The cleanout systems use CCT combined with a proprietary downhole switchable jet pump to remove solids and liquids. Liquid pumped down the inner coiled tubing string through the jet pump nozzle creates a localized pressure drop that essentially vacuums out wellbore fluids and entrained solids.

Meet objectives in a single run

While deployed in the well, the system can be switched between multiple operating modes to achieve all of your objectives in a single run.

The Sand-Vac mode removes wellbore solids without using nitrogen. The Well-Vac mode increases the localized pressure drawdown to vacuum wellbore fluids, drilling mud, stimulation fluids, and other liquids from the reservoir. A high-pressure jetting mode diverts all fluids through high-pressure nozzles to remove consolidated sand bridges or pump stimulation fluids.

The combined flow enters the jet pump diffuser and recovers pressure from the nozzle to drive the return fluids to the surface via the CCT annulus. This system uses a single-phase fluid that enables the cleanout to be performed with simplified logistics and reduced costs when compared with circulating nitrified fluids.

Applications

• Ultra-low-pressure reservoirs
• Extended-length and horizontal producing intervals
• Well cleanup and unloading
• Production profiling
• Heavy-oil and sand-producing wells
• Operating areas that are constrained in the use of nitrogen due to costs and logistics

Features and benefits

• Multiple operating modes
    – Sand-Vac mode
      • Removes sand and solids in a single run
    – Well-Vac mode
      • Vacuums drilling mud, stimulation fluids, and other reservoir fluids
      • Enables production inflow profiling
    – High-pressure jetting mode
      • Passes through hard sand bridges
      • Enables effective stimulation fluids placement
  
• Powered by Baker Hughes CIRCA software
    – Optimizes time on location by providing accurate job design, simulation, tool setup, and safe operating guidelines
  
• Nitrogen not required
    – Eliminates logistical problems
    – Reduces costs

Forward- and rear-facing jets fluidize solids, which are then sucked through a screen section and sent to the surface via the CCT annulus.

First-Time Catenary CCT Sand-Vac Solution Exceeded Production Target By 185%

Malaysia, South China Sea

Results

• Recovered 15,650 lb of sand from four wells, with 11,900 lb being recovered in a single run
• Removed enough sand from the wellbores to surpass target production by 185%
• Recorded 112 days of incident-free operations

Challenges

• High sand production in all four wells prohibited production and access to producing zones in the lower completion
• Wells had been shut in for several years
• Low bottomhole pressures
• Restricted platform access and crane capabilities
• Jack-up boat availability

Baker Hughes Solution

• Deployed Sand-Vac cleanout system to remove debris
• Used advanced wireless catenary-style CCT
• Designed and built specialized CT connector to enable conventional operations like fishing and sleeve manipulation.