Introduction to gas hydrates Jarle Husebø, UNC NVC FVC

Classification: Internal 2012-08-23

Overview

• Gas hydrates (what, why and where)

• Gas hydrates as a future resource

• Production technology

• Gas hydrate production history

• Major players

• Statoil’s research strategy

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Gas Hydrates: What?

Natural gas hydrate is a

clathrate, an inclusion

compound, where gas

molecules are suspended

within a crystalline

structure of water

molecules. Natural gas

hydrates are stable under

high pressure and low

temperatures .

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Hydrate structures

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512

51262

51264

435663

51268

Structure I

Methane, ethane,

Carbon Dioxide…

Structure II

Propane,

iso-butane…

Structure H

Methane + neohexane,

Methane + cycloheptane

Hydrate stability window

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GHSZ: Gas Hydrate Stability Zone

GHOZ: Gas Hydrate Occurrence Zone

BGHZ: Base Gas Hydrate Zone

BGHZ

GH

SZ

Depth

Temperature

GH

OZ

BGHZ

GH

SZ

De

pth

Temperature

Base Permafrost

Gas Hydrates: Why?

0,1

1

10

100

1000

10000

1970 1980 1990 2000 2010

Est.

CH

4 in

hyd

rate

(1

01

5 S

m3)

Year

Conventional gas reserve

Most confident estimate

USA energy consumption over

1000 years at current rate

Sloan and Koh (2008)

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Reservoir quality

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1

2

3

Modified from Boswell 2009

Marine sands

Fractured muds

Mounds

Undeformed muds

Arctic sands 85-10,000 tcf gas

(≤ 2.8·105 GSm3)

(≤ 1.7·1012 boe)

~100,000 tcf gas

(~2,8·106 GSm3)

(~1,7·1013 boe)

Hydrate in sands • Gas hydrate resources housed in sand

reservoirs

• Shallow “conventional” reservoirs

1

Solid hydrate • Vein-filling, nodules and massive seafloor

mounds

• Low resource density/environmentally

sensitive

2

The “Background” • Disseminated gas hydrate in fine-grained

marine sediments

• Large volumes

• Very low (1-3 %) resource density

3

◄◄ Coarse-grained continental sand

◄ Pore-filling marine turbidite sand

Vein-filling in clay Nodules in clay Massive sea floor mounds

Disseminated in mud

Korea India GoM

China

Canada Japan Gas-hydrate-bearing sands

seem the most feasible initial

targets for energy recovery

Modified from Johnson (2011)

Gas Hydrates: Where?

Classificati

on: Internal

2012-03-12

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Modified from Hester and Brewer (2009)

Hydrates in the industry today

• Flow assurance

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Production strategies for gas hydrates

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• Pressure depletion

• Heating

• Direct exchange with more stable hydrate former (e.g. CO2)

(Fire in the ice, May 2011, DOE)

Pressure depletion

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• Advantage

− No need to add energy

− Pressure support from hydrate

dissociation

• Disadvantage

− Dissociation is endothermic and will

cool down the system

− Vast amounts of water produced with

the gas

− Removing hydrate from consolidated

sediments may compromise structural

integrity

Temperature

Dep

th/P

ressu

re

seafloor

Heating

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• Advantage

− Heating will counteract the cooling

during dissociation

• Disadvantage

− Need to add large amounts of energy

to the system

− Vast amounts of water produced with

the gas

− Removing hydrate from consolidated

sediments may compromise structural

integrity

Temperature

Dep

th/P

ressu

re

seafloor

Direct exchange with more stable hydrate former (e.g. CO2)

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• Advantage

− No dissociation of hydrate. Keeping

structural integrity

− Carbon neutral production process

− Long term storage of CO2

• Disadvantage

− Needs permeability/connectivity to

access the entire reservoir with CO2-

injection

− The exchange process is based on

liquid-solid diffusion and is inherently

slow (there are ways to speed this up)

Temperature

Dep

th/P

ressu

re

seafloor

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Hydrate timeline

1960 1970 1980 1990 2000 2001 2002 2003 2004 2005

1969

Messoyakha

starts

production

1971

Imperial oil

discovers

hydrates in

Northern

Canada.

Mallik site

1998

First hydrate

research well

at Mallik site

1999

Japan: Drilled

first offshore

hydrate

research well

Korea: KIGAM

initiate hydrate

program

Japan: MH21

was created.

Ultimate goal to

make offshore

production from

hydrates viable

by 2018

2001

2002

Mallik: Three

research wells

drilled. 470 Sm3

of gas produced

by

depressurization

2003

Alaska:

Dedicated

hydrate

research

well drilled

2004

Japan: MH21

phase 1. 32

wells drilled

offshore to map

the Nankai

Trough

Korea: BSR

indicating

hydrate in the

Ulleung basin

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

2006

India: NGHP

expedition.

Four separate

legs of drilling.

One site

showed 128m

hydrate

2007

Alaska: BP

drills hydrate

research well

China: First

hydrate

expedition.

Three sites

show hydrates

Korea: First

hydrate

expedition.

Three sites

show hydrates

2008

Mallik: Second

production test

finished

(initiated in

2006). 13 000

Sm3 of gas was

produced over

a six day period

2009

Japan: MH21

starts Phase 2

with goal of two

offshore

production

tests

2010

Korea: Drilled

10 sites. 10

LWD and 2

wireline logging

and vertical

seismic

profiling.

2012

Alaska:

ConocoPhillips

CO2 injection

test (Ignik

Sikumi).

Japan: Drilled

first offshore

production well

2013

Japan:

Offshore flow

test

2014 -

2014

Korea:

Offshore

production test

2015

Japan: Long

term offshore

production test

Alaska: BP

planning for

production test

(date uncertain)

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Hydrate players and activity

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• Increase research activity

on hydrate as a resource

using our extensive

knowledge of hydrate as a

production problem

• Evaluate possible long-

term production test

Statoil’s research strategy

Introduction to gas hydrates

Jarle Husebø

Senior Researcher Reservoir Technology

jahuse@statoil.com

Tel: +47 900 19 805 www.statoil.com

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