1. Sand Control Fundamentals & Design
D. Koukhani / A. Hooshmand

2. HOW SANDING OCCURS
In most sandstone reservoirs sanding occurs in two stages:
First, the rock fails mechanically in the near wellbore area because of changes in and redistribution of the stresses as the bore is drilled or produced. Mechanical failure does not necessarily mean immediate sand production.
Then after the rock has failed, viscous drag forces generated by the flow of production fluids erode the failed material into the wellbore and up the flow path to surface.
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3. Main Geological Characteristics of Sandstone Reservoirs
Sandstone minerals can be split into three main groups:
Detrital residue
Secondary detrital residue
Chemical precipitates
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4. Main Geological Characteristics of Sandstone Reservoirs
Sandstone minerals:
Detrital residue:
Contain minerals from a source rock that have been transported and deposited mechanically, with quartz and feldspar typical of this group.
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5. Main Geological Characteristics of Sandstone Reservoirs
Sandstone minerals:
Detrital residue
Secondary detrital residue:
Clays are representative of secondary detrital minerals that have also been transported and deposited mechanically.
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6. Main Geological Characteristics of Sandstone Reservoirs
Sandstone minerals:
Detrital residue
Secondary detrital residue
Chemical precipitates:
Minerals deposited from solution by chemical or biochemical processes.
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7. Main Geological Characteristics of Sandstone Reservoirs
1. Quartz:
Concentration range of 50 – 70% can form up to
99% of the rock.
2. Feldspar:
Concentrations of up to 12%, the next most
common sandstone minerals after quartz.
3. Heavy mineral
4. Cementing material
5. Other
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8. Formation of Sandstones
Sandstones, like all sedimentary rocks are produced by a combination of
Weathering of existing rocks (igneous, metamorphic and sedimentary-older sedimentary).
Transport and erosion of the weathered material and diagenesis.
Weathering results in the breakdown of the existing rock into smaller particles. These are then moved by wind, water, gravity or a combination of the three.
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9. Classification of Sandstones
Sandstones have been classified by various criteria such as particle size or shape, sorting, mineralogy of the grains or of the cementations material etc.
One common method uses the following classification by mineral content:
Arkoses
Greensands
Greywackes
Sandstones are also classified by their grain size:
Coarse Grained Sandstone.
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10. Particle Size Measurement
Wentworth scale is used to measure grain size:
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11. Particle Size Measurement
Methods:
There are two common methods used for determining the particle size distribution of a sedimentary rock:
Sieving
Laser Diffraction
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12. Particle Size Measurement
Sieving
Advantages:
Cheap & Usable
Key Disadvantages:
Not possible to measure sprays or emulsions
Measurement for dry powders under 38 microns very difficult
Clays difficult to measure
Not high resolution
Particles not very well dispersed
Needs at least 20g
Does not measure below 45 microns
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13. Particle Size Measurement
Laser Diffraction
Advantages:
Flexibility
Dry powders can be measured directly
Liquid suspensions and emulsions can be measured
Entire sample is measured
Quicker than sieving
Sample size depends on particle size but typically <1g
Measures average diameter of particles
High resolution
Key Disadvantages:
Equipment is expensive – specialist test facilities required.
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14. Comparison between LDS & Sieve Analysis
The four main parameters utilized from the grain size distribution analysis are D10, D40, D50 and D90.
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15. Sampling Methods
There are two fundamental methods of sampling sandstone reservoirs – downhole coring and surface sampling. These can be subdivided into:
Rotary coring
Sidewall coring
Bailing
Surface sampling of circulated or produced material
Samples can be obtained from:
Cores
Drill Cuttings
Junk Baskets
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16. Sand Face Completion
The choice of equipment which is run across the formation interval forms the sand face completion.
The selection will be based on whether the well is
Open hole or cased and perforated,
Vertical, deviated or horizontal,
and
Expected production conditions
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17. Sand Face Completion
Choices of completions for sand control across the formation face:
Screens
Frac-Pack
Gravel Pack
ESS / CHESS
Slotted Liner
Chemical Considerations
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18. Screens
Different types of screens that use a different filtering media exists:
Wire-wrapped screens
Have a base pipe with slots or holes around the circumference that is either single-wire wrapped or surrounded by cylindrical sieves of various mesh sizes.
Pre-packed screens
Employ a different filtering media. A layer of consolidated resin coated gravel is placed around the internal screen assembly and is supported by a shroud or external screen.
Premium screens
Premium screens are typically an all-metal design, with a metal mesh filtration media and a protective outer metal shroud.
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19. Wire Wrapped Screen
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20. Pre-Packed Screen
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21. Premium Screen
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22. Frac-Pack
Frac-pack is a sand control method by which a propped hydraulic fracture of limited length is created into a weak or unconsolidated reservoir.
Wells producing from unconsolidated reservoirs using frac-packs require lower drawdown pressures to produce.
The main reasons for using frac-packing as a sand control technique are:
By passing formation damage
Reduce water coning
Controlling sand production
Enhance productivity in low permeability formations
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23. Gravel Pack
In a gravel pack, the annulus between the wellbore and a base perforated pipe with wirewrapped screen, is filled with gravel.
Advantages
Productivity impairment can be minimized by design
Especially useful for heterogenous sands in long productive intervals
Disadvantages
Complicated workovers
Chemical compatibility of WBM and produced fluids
Risk of incomplete gravel pack leading to premature screen failure
Screen damage from erosion and corrosion is a major concern
Chemical compatibility of OBM and carrier fluid
Can be difficult to use in deviated and horizontal wells
Flow control and isolation is complex
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24. Expandable Sand Screen (ESS)
Unique approach to solve sand control problems.
Large OD expanded to contact the wellbore stabilizes formation.
System designed to resist erosion and plugging.
Large ID to maximize well intervention options.
Large and uniform flow area to optimize production.
Simple deployment minimizes operations costs.
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25. Slotted Liner
tubing sections with a series of slots cut through the walls in an axial orientation.
The main limitation of slotted liners is their flow area – an average of 3% and maximum of 6% is accepted.
Flow areas of more than 6% are detrimental to the tensile strength of the pipe.
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26. Slotted Liner Common Slot Profiles
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27. Chemical Considerations
Used in formations with little or no cementitious material.
A major benefit is that the wellbore is left free of obstructions.
Fundamental principle =
bond the quartz grains together using a liquid resin.
This will then provide an artificial cementing material between the grains.
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28. Expandable Sand Screens (ESS) Design & Construction

29. ESS Design 1 EST Base Pipe 2 3 Woven Filter Outer Shroud Slots open up
Sheets slides over one another
Slots open up
Expandable Base Pipe
UNEXPANDED
Overlapping Layers of Filter Media
EXPANDED
ESS has 3 main components, slotted base pipe, slotted outer shroud and filter media in between.
Outer shroud protects the weave during deployment.
During expansion the base pipe and outer shroud slots open up and thus expand. The filter media consists of overlapping layers and these slide over one another as the pipe expands.
It is important to note that the weave aperture of the filter media does note change during expansion – expansion is not critical to ensure effective sand control/clean-up/plugging resistance
Expandable Outer Protective Shroud
No change in weave aperture
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30. ESS Manufacture 3 LAYERS SANDWICHED TOGETHER EST Base Pipe Petroweave1 2
Outer Shroud 3
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31. Sizes Available External diameter post expansion 3 7/8” 4 1/2”
3 7/8” /2”
5 7/8” /4”
8 3/8” /8”
2 7/8” ESS
4” ESS
5 1/2” ESS
These sizes indicate the design limits of the ESS screen.
For information only: Expansion ranges are for maximum expansion with fixed cone. When ACE compliant expansion is used final OD’s are less than stated above because expansion is limited by the stroke of the pistons on the tool
3 1/2” ESS
4 1/2” ESS
4 ½” Csg. / 4” OH 7” Csg. / 6” OH /8” Csg. / 8 ½” OH
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32. Axial Compliant Expansion Tool
The ACE Tool is run
after the fix cone for
Borehole contact.
1800 psi hydraulic actuation
Compliant Expansion speed 10ft/min
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33. Compliant Expansion Benefits
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34. Value of ESS - NISOC Total Production = 10,500 bpd
Increase with ESS Screens = 5,200 bpd
= $208,000/day!!!
Project costs (excluding workover) recovered in 5 days
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