Introduction to gravel pack techniques

Gravel Pack 

Consists of sized particles placed in the annular space between an unconsolidated formation and a centralized screen.

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Open or cased hole.

Sand - Gravel - Screen

GP Hardware Main Components

Gravel Pack Installation 

Hardware is installed with : Rig Coiled Tubing (Snub-in) Wireline

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Gravel is transported by fluid in slurry form.

Cased Hole - Internal Gravel Pack Packer  Blank Casing

Screen

Gravel

Formation Sand

Perforation Tunnels

Cased Hole - with Service Tool Outer String

Inner String Service Tool

GP Packer Crossover Blank Pipe

Screens Sump Packer

Washpipe

IGP Considerations 

Isolate production from undesirable zones.

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Reliable drilling and completion methodologies.

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Requires efficient perforation system.

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Poor perforation pack may lead to low productivity.

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Easier workover compared to EGP.

Poor Perforation Pack Efficiency

Open Hole - External Gravel Pack

EGP Considerations 

Can be under-reamed, increasing wellbore area.

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No damage due to poor perforation pack efficiency.

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Hole stability is a concern while drilling and completion.

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Horizontal completions

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Water production control may become impractical.

Gravel Pack Systems 

Circulation

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Squeeze

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Wash Down

Circulation System 

Fluid may leak to the formation, circulate back to the surface or both.

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When pumping slurry, gravel will be placed inside perforation  tunnels and annular casing-screen.

Squeeze System 

Fluid leaks to the formation. No returns  to the surface.

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Fluid may flow inside  the screen.

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When pumping slurry, gravel will be placed inside perforation  tunnels and annular casing-screen.