SOFREGAZ US

REQUIREMENTS FOR CAVERN

STORAGE

Paul Bieniawski

SPE Appalachian Storage Group

February 19, 1997

SOFREGAZ US

OUTLINE

• History

• Comparisons

• Cavern Storage Requirements

• Cavern Storage Operations

• Effect of Variables

• Questions

SOFREGAZ US

HISTORY

• 1961 Southeastern Michigan Gas converts abandoned

brine caverns in bedded salt to gas storage.

• 1963 Saskatchewan Power Corporation commences

operations of first caverns designed specifically for gas

storage in bedded salt.

• 1964 First cavern storage in Armenia.

• 1966 First cavern storage in West Germany.

• 1968 First cavern storage in France.

• 1970 Transcontinental Gas Pipe Line Corporation commences

operations of first caverns designed specifically for gas

storage in a salt dome.

• 1974 First cavern storage in United Kingdom.

• 1981 First cavern storage in Denmark.

SOFREGAZ US

COMPARISONS

RESERVOIR AQUIFER REEF MINE CAVERN

BASE GAS59% 67% 40% 28% 29%

CAPACITYPER

WELL 470 785 1,225 165 1,890

DELIVERABILITYPER

WELL 3,320 3,395 20,930 10,940 72,715

SOFREGAZ US

REQUIREMENTS

• Location

• Salt

• Caprock

• Raw Water

• Brine Disposal

SOFREGAZ US

LOCATION

• Acreage

• Proximity to Pipelines

• Proximity to Markets

• Proximity to Raw Water Supply

• Proximity to Brine Disposal

• Proximity to Utilities

SOFREGAZ US

SALT

• Salt Purity

• Existence and Nature of Caprock

• Existence and Nature of Interbeds

• Distribution of Interbeds

SOFREGAZ US

ADVANTAGES OF SALT

• Impervious to Hydrocarbons

• Very High Compressive Strength

• Ability to Yield and Divert Stresses

• Ability to Flow and Heal Fractures

SOFREGAZ US

LOCATION OF SALT BASINS

SOFREGAZ US

CAPROCK

• Not Present in Bedded Salts

• Exact Origin Unknown

• Believed to be Accumulation of Insolubles

Originally Transported in the Salt

• Usually Comprised of Anhydrites, Gypsum,

and Dolomite

• May be Highly Fractured with Numerous Lost

Circulation Zones

SOFREGAZ US

RAW WATER

• Fresh, Brackish, or Unsaturated Brine

• Sources

• Aquifers

• Rivers

• Canals

• Lakes

• Municipal Supplies

SOFREGAZ US

BRINE DISPOSAL

• Wells

• Chemical Feedstock

• Evaporation Plants

• Solar Evaporation

• Surface Waters

• Displacement

SOFREGAZ US

LEACHING OPERATIONS

SOFREGAZ US

DIRECT CIRCULATION

SOFREGAZ US

REVERSE CIRCULATION

SOFREGAZ US

CAVERN SHAPING

Top of Insolubles

Raw Water Injection

Brine Return

Blanket Level

Production Casing

Brine Return

Raw Water Injection

SUMP DEVELOPMENT CAVERN DEVELOPMENT

SOFREGAZ US

CAVERN MECHANICS

Sump Building Partially Cavern

BRINERETURN

INSOLUBLESWATER INJECTION

BLANKETLEVEL

BRINERETURN

WATERINJECTION

BOTTOMOF CAVERN

BRINE RETURN

BLANKET LEVEL

BOTTOM OFCEMENTED CASING

BRINERETURN

DEPTH OFORIGINAL HOLE

BLANKETLEVEL

INSOLUBLES

INSOLUBLES

Near Completion Developed Cavern Near Completion

WATER

INJECTI

ON

SOFREGAZ US

CAVERN OPERATIONS.

Injection

Facilities

Withdrawal

Facilities

Brine Pond

GASEXPANSION

BRINEDISPLACEMENT

GasHeater

PCR

GL

YC

OL

AB

SO

RB

ER

SOFREGAZ US

OPERATIONS (cont’d)

M

STORAGE

CAVERN

STORAGE

CAVERN

Injection

Facilities

Withdrawal

Facilities

SOFREGAZ US

EFFECT OF VARIABLES

• Minimum Pressure

• Maximum Pressure

• Insolubles Percentage

• Bed Thickness

SOFREGAZ US

MINIMUM PRESSURE

GRADIENT

0

0.4

0.8

1.2

1.6

0.1 0.15 0.2 0.25 0.3

Minimum Pressure Gradient, psi/ft

Ba

se

Ga

s, B

cf

SOFREGAZ US

MAXIMUM PRESSURE

GRADIENT

2.5

2.7

2.9

3.1

3.3

3.5

3.7

0.6 0.65 0.7 0.75 0.8 0.85 0.9

Max Pressure Gradient, psi/ft

To

tal C

ap

ac

ity

, B

cf

SOFREGAZ US

INSOLUBLE CONTENT

0

0.2

0.4

0.6

0.8

1

0 5 10 15 20 25 30

Insoluble Content, % vol

Ca

ve

rn V

olu

me

, M

illio

n B

arr

els

SOFREGAZ US

BED THICKNESS

0

0.5

1

1.5

2

2.5

100 150 200 250 300 350 400

Bed Thickness, ft

Ca

ve

rn V

olu

me

, M

illio

n B

arr

els

SOFREGAZ US

QUESTIONS ????