This document discusses well stimulation techniques used to increase oil and gas production. It describes two main types of well stimulation: acidizing and hydraulic fracturing. Acidizing involves injecting acid to dissolve rock and increase permeability. There are two types of acidizing - matrix acidizing below fracture pressure to remove damage, and fracture acidizing above pressure to create open channels. Hydraulic fracturing uses pressurized fluid to crack rock, with proppant like sand injected to hold the fractures open and increase conductivity. Both techniques aim to extend fractures and improve hydrocarbon flow into the wellbore.

1. SLBS ENGINEERING COLLEGE
WELL STIMULATION
Submitted by
BHAVESH KUMAR
14ESLPE007
Submitted to
Dr. R.K. BAWA
(ACADEMIC DIRECTOR)
DEPT. OF PETROLEUM ENGINEERING

2. CONTENTS
INTRODUCTION
TYPES
ACIDIZING
MATRIX ACIDIZING
FRACTURE ACIDIZING
HYDRAULIC FRACTURING
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3. INTRODUCTION
• Well stimulation is a well intervention performed
on an oil or gas well to increase production by
improving the flow of hydrocarbons from
the drainage area into the well bore.
• Well stimulation technique used for extending
the perforation tunnels and fractures.
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4. WELL STIMULATION
TYPES OF WELL STIMULATION TECHNIQUE
1) Acidizing
2) Hydraulic fracturing
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5. ACIDIZING
• Acidizing also termed as Acid Stimulation.
• Acid stimulation refers to using reactive acids
to increase permeability in wells.
• It dissolves various acid-soluble solids
naturally present in the rock matrix or as
formation damage.
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7. ACIDIZING
Two basic types of acidizing are
1. MATRIX ACIDIZING
2. FRACTURE ACIDIZING
It is characterized
by INJECTION RATE
and PRESSURE.
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8. ACIDIZING
 MATRIX ACIDIZING
• In Matrix acidizing acid is pumped into the
formation below the fracture pressure.
• It removes acid-soluble damage.
• This method is used for both sandstone and
carbonate formation
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9. MATRIX ACIDIZING
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10. ACIDIZING
 FRACTURE ACIDIZING
• In Fracture acidizing acid is pumped into the
wellbore, above the fracturing pressure of
reservoir rock.
• It creates long and open channels.
• It is usually carried out on carbonate
reservoirs, which have lower permeability
than sandstone
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11. ACIDIZING
 ACIDS USED IN ACIDIZING
• Hydrochloric acid (HCL)
• Acetic acid (CH3COOH)
• Formic acid (HCOOH)
• Hydrofluoric acid (HF)
• Mud acid (HCL-HF)
• Sulfamic acid (NH2SO3H)
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12. ACIDIZING
 Acid additives
• Surfactant
• Corrosion inhibitor
• Anti-sludge agent
• Suspending agent
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13. Hydraulic fracturing
• Hydraulic fracturing is usually termed as
fracking and hydrofracturing.
• This stimulation method have two major steps
1. Create crack in rock formation using acid
2. Proppant injection
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14. Hydraulic fracturing
• The objective of hydraulic fracturing is to
increase well productivity by creating a highly
conductive path.
• In Hydraulic fracturing rock is fractured by a
pressurized liquid, the conductivity is
maintained by propping with sand to hold
the fracture faces apart.
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16. Hydraulic fracturing
Composition of fracture fluid
• Water
• Proppant
• Gelling agent (guar gum)
• Foaming agent
• Compressed gases (N2 ,CO2, air)
• Corrosion inhibitors
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17. HYDRAULIC FRACTURING
STAGES
1. SPEARHEAD STAGE
2. PAD STAGE
3. PROPPANT STAGE
4. FLUSH STAGE
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18. • SPEARHEAD STAGE- Mixing water with
acid, used to clear debris and create path way.
• PAD STAGE- Inject fluid before proppant to
break the formation.
• PROPPANT STAGE- Injection of water and
sand and remains in formation.
• FLUSH STAGE- At last fresh water is
pumped into wellbore.
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19. Hydraulic fracturing
Proppant
• The proppant is a granular material that
prevents the created fractures from closing
after the fracturing treatment.
• Types of proppant
1. Silica sand
2. Resin-coated sand
3. Bauxite
4. Ceramics
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