Acid Fracturing

Principles of Acid Fracturing

1Acid

Acid Fracturing Basics 

Acid is injected above fracturing pressure – A hydraulic fracture is created

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Limestone and Dolomite Fracture faces are dissolved and etched etche d – Conductive channels are created c reated

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Length of etched fracture – Determined by acid type volume strength lea!o" parameters reaction rate and spending rate#

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$"ectiveness determined by – Fracture length – Fracture conductivity

2Acid

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Candidates for Acid Fracturing

Cleaner limestone and Dolomite forma formations tions – &ust have good fractur fracture e containment to generate length

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Dirty carbonate roc!s '( )*+ solubility in ,Clare poor candidates – Acid etched channel .ill be impaired – /elease of insoluble material .ill plug the channel

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Chal! formations may not be suitable – 0oft unable to retain conductivity after closure

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ot applicable to sandstone formations – ,Cl even ,F .ill not adeuately etch sandstone

fracture face

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– &aterials released through dissolution .ill plug the fracture

%Acid

Acid 4 5ropped Fracturing Comparison Acid Fracturing

5ropped Fracturing

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$uipment67reatment

Less complicated

&ore complicated

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5roppant problems

o

8es

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5roppant 7ransport 5roblem o

8es

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Fluid Loss Control

5oor

Better

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Candidates 0andstones

Carbonates 9nly

Carbonates :

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/esidual Damage in Fracture

o 8es

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Fracture Length Achievable 0horter

Longer

3Acid

Factors overns fracture .idth and acid transport along length