7.2 Sand Control Techniques.pdf

Sand Control Techniques Reservoir Stimulation Techniques

Dr Sia Chee Wee (Petroleum Engineering Department)

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What we learnt in last lecture • Reason for Sand Production • Factors Affecting Sand Production • Formation Sand Characteristics and Classification • Predicting Sand Production • Sand Production Monitoring

Dr Sia Chee Wee (Petroleum Engineering Department)

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Content • Introduction • Sand Control Techniques • • • • • •

Reactive Techniques Resin Consolidation Standalone Screens Gravel Pack High Rate Water Pack Frac-Pac

• Summary

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Learning Outcomes • At the end of this session student will be able to understand the techniques for sand control

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Introduction • The objective of any sand control completion is to control sand while maintaining/maximizing hydrocarbon production • Various techniques are used in the industry, including reactive, mechanical and chemical • Selection of a particular technique for a well depends on many factors • • • •

Reservoir and wellbore conditions Availability of surface and downhole equipment Completion cost Etc. Dr Sia Chee Wee (Petroleum Engineering Department)

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Sand Control Techniques • Reactive • Surface Sand Handling • Rate Control

• Chemical • Resin Consolidation

• Mechanical • • • • • •

Generally Increasing Cost and Complexity

Slotted liners Standalone screens Pre-packed screens Gravel packs High rate water packs Frac packs

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Reactive Techniques Surface Sand Handling

• Allow sand to be produced and handle/ disposed at surface • Surface handling equipment is required

• Downhole equipment/ tubulars still susceptible to erosion and failure • Wellbore access can be impacted by accumulation of sand • Generally not feasible as a long term solution

Dr Sia Chee Wee (Petroleum Engineering Department)

Rate Control

• Restricted Production rate to minimize drag forces and likelihood of sand production • Cheap and easy option but results in lost production • Rate will need to be continuously reduced which is usually not viable economically

• Generally not feasible as a long term solution

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Resin Consolidation • Pump commercially available liquid resins into formation: • Epoxies • Furan (Including furan/phenolic blends) • Pure phenolic

• Consolidates individual sand grains and increases unconfined compressive strength • Increase in UCS must be sufficient to withstand drag forces at desired production rate Dr Sia Chee Wee (Petroleum Engineering Department)

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Resin Consolidation • Resin usually pumped in liquid form but can also be applied to the gravel (resin coated gravel) • Catalyst or curing agent required for hardening which can be mixed with resin or pumped separately (activates with time and/or temperature) • Treatment guidelines • Need a good cement job • Perforations and near wellbore should be cleaned to ensure resin treatment is effective • Ideal for short zones with uniform permeability

Dr Sia Chee Wee (Petroleum Engineering Department)

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Resin Consolidation Pros

• Good technique for marginal well with relatively low flow rates • Comparatively inexpensive and easy to install

• No hardware deployment required • Leaves wellbore open for large completion

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Cons

• Difficult to get good zonal coverage (limited to perforated intervals of 20 – 30 ft) • Limited to formation with temperature < 250 deg F • Generally leads to impairment of permeability • Careful treatment planning required as many stages involved

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Standalone Screens • Screens (no gravel pack) installed across producing interval: • Slotted Liner • Wire Wrap • Premium

• Screens allow hydrocarbon to pass but contain formation sand • Generally sized for D10 of the formation PSD to retain larger particles but allow fines to be produced Dr Sia Chee Wee (Petroleum Engineering Department)

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Standalone Screens • Sand control mechanism relies on formation of a natural sand pack • Larger grains form stable arches (or bridges) agains the filter with progressively smaller grains being held behind them • Generally used in formations with well-sorted, clean sands and relatively large grain sizes • The industry as a whole is trying to extend the application envelope of these types of completions

Dr Sia Chee Wee (Petroleum Engineering Department)

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Slotted Liners • Pipe with fixed size slots to prevent sand production • Manufactured by machining slot openings through oilfield tubular using rotary saws or laser • Slot available only in rage of 0.012” to 0.250” (increased cost for slots <0.02”) • Open flow area varies between 1 – 4 % • Generally used for low cost wells with large grained uniform sands Dr Sia Chee Wee (Petroleum Engineering Department)

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Slotted Liners Pros • Relatively simple solution good for low cost wells • Fized slot size good for wellsorted, clean sands with relatively large particle sizes • Comparatively inexpensive and easy to instal

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Dr Sia Chee Wee (Petroleum Engineering Department)

Cons Low open flow area results in higher pressure drops during production Expensive to manufacture with slot size less than 0.02” Natural sand pack is inherently unstable and can breakdown with changes in rate or shutdown Susceptible to plugging, especially in poorly sorted sands 14

Wire-Wrap Screens • Wire wrapped around a perforated base pipe with fixed gap between wires providing sand control filter mechanism • Gap size can be between 0.006” and 0.02”(typically keystone or house shaped) • Screen jacket can be slip-on or wrap-on type • Significantly higher flow area than slotted liners (6-12%) • Gap size tolerances are typically plus 0.001” and minus 0.002” Dr Sia Chee Wee (Petroleum Engineering Department)

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Wire-Wrap Screens

Dr Sia Chee Wee (Petroleum Engineering Department)

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Wire-Wrap Screens • • • •

Pros High open flow area results in low pressure drops during production Robust, proven design Fixed and controllable gap size Lower cost than premium screens

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Cons Lower flow area than premium screens Difficult to manufacture with gap size < 6 gauge Screen plugging could be an issue in poorly sorted sands or due to poor completion practices Limited applicability as standalone screens in non-uniform sands

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Premium Screens • Different types of filters offered by various companies:

• Multiple layers of sintered woven wire mesh that form a filter • Compressed stainless steel wool as filtration medium

• Gap size cannot be directly controlled but is quoted as an average value • Include a drainage layer to minimize erosion and pressure drop during production Dr Sia Chee Wee (Petroleum Engineering Department)

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Premium Screens Pros Cons • High open flow area (20 • Comparatively high cost – 40%) results in low • Relatively new, pressure drops during unproven technology production • Cannot replace gravel • Better plugging packs in all types of resistance than other reservoir types of screens • Better sand retention capabilities than other types of screens Dr Sia Chee Wee (Petroleum Engineering Department)

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Pre-Packed Screens • Layer of resin-coated gravel prepacked between two concentric screens • Can be used as standalone screen or in conjunction with a gravel pack • Gravel layer acts as a secondary or backup filter (e.g. in case of void in gravel pack) • Thickness and size of gravel can be varied for specific conditions • Not commonly used today Dr Sia Chee Wee (Petroleum Engineering Department)

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Pre-Packed Screens Pros • Gravel layer provides backup for voids in gravel pack • Cheaper than premium screens and gravel pack

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Cons Tend to plug easily, leading to high skins and eventual failure due to hot spots For a given basepipe, they have a larger OD than other screens Cannot replace the sand control effectiveness of a gravel pack Not commonly used

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Gravel Pack • Screen placed in the wellbore and the surrounding annulus packed with high permeability gravel • Gravel is sized to retain the formation sand and the screen is sized to retain the gravel • Gravel pack stabilizes formation with minimal impairment to well productivity • Complete packing of wellbore annulus is critical for preventing movment of formation sand Dr Sia Chee Wee (Petroleum Engineering Department)

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Gravel Pack • Alpha/Beta and Alpha/Alpha

• Brine carrier flud with low gravel concentration • Primarily used in horizontal open hole completions

• Slurry Pack

• Viscous carrier fluid with higher gravel concentration • Can avoid fracturing by allowing placement at lower pump rates

• Shunt Tubes

• Slurry pack with the use of shunt tube technology to overcome bridging

Dr Sia Chee Wee (Petroleum Engineering Department)

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Gravel Pack •

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Pros Generally accepted as the most successful and widely applicable sand control technique Proven effective in controlling sand production in poorly sorted and fine sands Provides an additional filtration layer via the gravel to contain formation sand Stabilizes the open hole

Dr Sia Chee Wee (Petroleum Engineering Department)

Cons • Expensive in comparison to standalone screens and resin consolidation • Successful design and execution may present challenges depending on reservoir/wellbore conditions • Requires pumping equipment which brings additional cost and logistical considerations

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High Rate Water Pack • Gravel packs pumped above fracture pressure to initiate small fractures in the formation • Aim to place very short (5 - 15 ft) and relatively thin fractures • Generally use brine carrier fluis at low gravel concentration • Important to pack both perforations and wellbore annulus with gravel to ensure success • Can be cheaper alternative to frac-packs in low cost wells Dr Sia Chee Wee (Petroleum Engineering Department)

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High Rate Water Pack •

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Pros Provides some of the benefits of fracturing (e.g. bypass near wellbore damage) Saves cost of fracturing fluids and breakers Minimizes risk of fracturing into proximate water or gas zones Preferred over frac-packs in wells requiring low cost completion

Dr Sia Chee Wee (Petroleum Engineering Department)

Cons • Can be more expensive, complex and risky than gravel pack • Requires the same equipment as a frac-pack, which brings additional cost and logistical considerations • Short, thin frac do not provide the high conductivity and and low skin associated with fracpacks 26

Frac-Pack • Simultaneous hydraulic fracturing of the formation and placement of gravel pack • Used primarily in cased hole wells with moderate to high permeability that are prone to sand production • Performed above fracturing pressure using viscous fluid with high gravel concentration • Typical designed for relatively short fractures (around 30-50 ft) with large width (>1”) Dr Sia Chee Wee (Petroleum Engineering Department)

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Frac-Pack • Bypasses near wellbore damage and creates a highly conductive path for fluid to flow • Lowers sand production by reducing flow velocity and drawdown • Potential to obtain negative skins and increases productivity • Can be more expensive, complex and risky than other sand control techniques Dr Sia Chee Wee (Petroleum Engineering Department)

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Frac-Pack • • • •

Pros Bypasses near wellbore damage Increases effective wellbore radius (can result in negative skin) Reduces sand production by lowering flow velocity and pressure drop Gravel pack prevents formation sand being produced

Dr Sia Chee Wee (Petroleum Engineering Department)

Cons • Increased cost, complexity and risk in comparison to other techniques • Not feasible in reservoirs without containment or those with proximate water/gas zones • Productivity limitations in wells with very high transmissibility (kh/m) due to presence of perforations

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Summary • A number of techniques are used in the industry to control sand production • Reactive techniques are usually not economically viable, so proactive techniques are required for longer term solutions • Chemical techniques are cheap and relatively easy to install but have limited applications (usually in marginal wells with low flow rates) • Mechanical techniques are the most commonly used with each having its own advantages and challenges • Technique selection depends on a number of factors including: • • • •

Reservoir conditions (permeability, pre/frac window, etc) Wellbore conditions (cased/open hole, deviation, etc) Cost Considerations Etc

Dr Sia Chee Wee (Petroleum Engineering Department)

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End of Section Thank You

Dr Sia Chee Wee (Petroleum Engineering Department)

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