Tot siens? Of nie?
CBM = Coal Bed Methane
A.
B.
Will the Springbok Flats
survive
the exploration for it
and the production of it?
Will the people of the Springbok
Flats allow it?
The answers to these questions
need to be informed by what we
consider as responsible interaction
between man and the ecology.
Should we allow ourselves to be
the aggressors on the natural
resources that have the capacity to
sustain our livelihood, provided we
use it judiciously?
Gaan ons dit prysgee?
Ons kan vandag besluit!
What is this thing, Methane?
A valuable source of energy = a fossil fuel!
Derived of micro-organisms acting on ancient biomatter.
Providing oxygen to Methane creates a combustible mix!
Once ignited, Methane produces energy and two new molecules.
Burning Methane unfortunately produces CO2.
Just like burning coal does.
Man and his environment are interdependent
entities. The sustainability of this system
depends ultimately on the choices man makes.
The relationship between man and the
environmental phenomena is characterised by
the socio-economic expectations man has for his
day-to-day livelihood.
The higher man’s living standard the higher is the
impact on Planet Earth’s resources.
Methane is not scarce!
It is all around us and has amazingly different origins
Our world has a growing need for more energy to keep
the wheels turning for 7,2 billion people.
One form of energy presents itself
in the form of Springbok Flats Methane.
The problem is that we live on top of it
and that it needs agressive impacts on the environment
to get to it in order for it to work for us!
The question is, how are we to balance
our needs and the needs of the natural environment
with the needs of the fuel industry?
Next
Coal Bed Methane is natural gas trapped in coal seams underground. To extract the gas,
after drilling into the seam, it is necessary to pump large amounts of water out of the
coal seam to lower the pressure.
It is often also necessary to frack the seam to extract the gas. This results in methane
migration, toxic water contamination, air pollution, increased carbon emissions and a
general industrialisation of the countryside. Impacts that are specific to CBM include
depletion of the water table and potentially subsidence.
How Is CBM extracted?
Within coal beds Methane is contained in solution and on cleat surfaces and is held in
place by hydraulic pressure. To develop these unconventional gas resources, Coal-bed
Methane projects involve the dewatering of coal beds which result in the production of
gas at the surface. Lowering of the hydraulic pressure by withdrawal of water from
wells completed in the coal-bed, allows the Methane to be released and recovered.
Coal-bed Methane projects typically cover large areas of land with producers drilling
hundreds of wells. Horizontal drilling is used to reduce the impact of land access issues.
Development of Coal-bed Methane resources generally involves five phases:
Phase I
General exploration involving identification of coal-area, characterization of coal (rank,
thickness, extent, depth of coal-seam etc.), identification of suitable areas for drilling;
and core drilling and testing for gas content, gas saturation and permeability of the coal.
Phase II
Geology, geophysics and geohydrology.
Phase III
Pilot project to determine the economic viability of a site. Project economics are
determined by a number of factors: well flow rates, well spacing, cost of drilling and
development, developing costs, ability to dispose of water cheaply, good land access
and market access.
Phase IV
Phased development
Phase V
Abandonment, with or without rehabilitation.
Hydrocarbon traps will differ in permeability:
Conventional gas = highest;
Gas shales = lowest
Coal-bed CBM = less; Tight gas = even less;
Methane Storage in Coal
Coal serves as both the source rock and the reservoir rock.
Hydraulic pressure, rather than a pressure seal or closed structure (common
for conventional oil and gas fields), is the major trapping force for CBM.
Coal is extremely porous but has low permeability (connected openings).
Gas storage in coal beds is more complex than
in most conventional reservoirs.
Coal contains unique properties for gas storage that are
not present in other reservoirs.
Coal-bed Methane is stored in four ways:
1)
2)
3)
4)
as free gas within the micropores and cleats (natural fractures in
the coal);
as dissolved gas in water within the coal;
as absorbed gas held by molecular attraction on surfaces of
macerals (organic constituents that comprise the coal-mass),
micropores, and cleats in the coal; and
as absorbed gas within the molecular structure of the coal
molecules.
The quality of
a reservoir
rock is
determined by
its porosity and
its permeability
In some cases most
of the CBM gas is
adsorbed on the
surface of the coal.
Pumping to release
the pressure is
here one option.
But before you can start pumping,
you have to master the world of pressure control drilling.
If not, a surface blow-out will surely get your attention!
Made simple!
NOT huge, continuous "pools" of gas but rather minuscule pores
between the grains with CBM that make up the rock matrix
= "reservoir rock “.
The real world is however not this simple: underneath and on top!
We still need to live and farm there!
Successful and simple pumping depends mostly on sufficient saturation:
That is the percentage of sediment pore space in the source rock
occupied by gas hydrate.
1. What about contamination on top and beneath the surface by pumping?
2. What about cross contamination between aquifers?
What if the gasbearing coal layer is too consolidated and unpermeable and
will require gas flow to be stimulated?
1. One possibility to achieve this is to FRACK.
2. The other option is CAVITATION.
What if the presence of Uranium and Radon endangers safe extraction,
production and use?
What if safe separation of the Uranium/Radon complex from the
Methane/coal is not econmically viable at production scale ?
CBM “produced water” is to be managed through some combination of
treatment,
disposal, storage, or use, subject to compliance with DWA regulations.
One way to get rid of CBM “produced water”
ARID = Aquifer Recharge Injection Device
NB!
Aquifers
differ in
salinity
and other
chemical
qualities.
ARID tool in the well-bore above the coal-seam, shows pumping the water
from the coal-seam to a shallower aquifer that contains water of similar
quality, but presents the real threat of cross aquifer contamination.
http://www.bigcatenergy.com/CBM-Environmental-Issues.aspx
Grouting while drilling? Afterwards is too late!
Hydraulic fracturing is used as a primary means of
stimulating gas flow in CBM wells.
Another gas stimulation technique, unique to CBM wells, is
known as cavitation (also known as open-hole cavity
completion).
Cavitation is a similar phenomenon to opening a shaken pop
bottle, only on a much larger scale. Water, and air or foam
are pumped into the well to increase the pressure in the
reservoir. Shortly thereafter, the pressure is suddenly
released, and the well violently blows out, spewing gas,
water, coal and rock fragments out of the well. This action is
sometimes referred to as "surging", and it is accompanied by
a jet engine-like noise, which can last up to 15 minutes.
http://www.energyjustice.net/naturalgas/cbm
What are the challenges to produce CBM
by stimulating gas flow? Order
Disorder!
What are the options?
What are the downsides?
1. Fracking:
NEEDS A BIG LOT OF WATER PLUS LOTS OF CHEMICALS
2. Cavitation:
NEEDS A LOT OF WATER PLUS CHEMICALS
3. Pumping:
DISTURBS AQUIFER BALANCE;
CREATES CROSS-CONTAMINATION OF AQUIFERS.
GAS LEAKS AND CONTRIBUTES TO AIR POLLUTION.
Is it sustainable?
Do we want it?
Will our area’s socio-economic fabric survive it?
If dewatering stops, the coal seam and the well fill with water, which
automatically prevents the gas from being released.
Forever Resorts – Possible sources of heat
The water issuing from a hot spring is heated by geothermal heat,
i.e. heat from the Earth’s mantle. In general, the temperature of rocks
within the earth increases with depth.
The rate of temperature increase with depth is known as the
geothermal gradient.
If water percolates deeply enough into the crust, it will be heated as it
comes into contact with hot rocks. The water from hot springs in nonvolcanic areas is heated in this manner.
Warm springs are sometimes the result of hot and cold springs mixing
but may also occur outside of volcanic areas, such as warm springs.
Should we allow anybody to “play” around Bela-Bela’s hot spring?
CBM development has a huge "footprint" on the landscape and the process used to
extract Coal-bed Methane depletes local aquifers, causing groundwater levels to drop and
wells to run dry. The accumulation of Coal-bed Methane wells and associated compressor
stations, service roads, power lines and related infrastructure fragments bushveld habitat,
harms wildlife, and the ecology as well as the sense of place and the socio-economic
fabric. http://www.sagebrushsea.org/threat_energy_development.htm
Aerial view of the Jonah natural gas field, upper Green
River Valley, Wyoming, 2001 - SkyTruth
A close-up view you can smell!
http://www.alandoutoftime.com/mediaresources.html
Só sal dit
oor ‘n paar jaar
vanaf Buyskop lyk –
as ons nie wakker loop
en vasstaan nie.
Coal Bed Methane: The Evil Twin of Shale Gas
In common with other unconventional gas extraction, such as Shale Gas, CBM wells do
not produce large amounts of gas per well and production declines very quickly.
It is therefore necessary to drill large numbers of wells, covering huge swathes of the
landscape.
CBM exploitation began in the US and over 55 000 CBM wells have been drilled in the
last decade or so, mostly in the western states (Colorado, New Mexico and Wyoming in
particular).
In Australia, where it is known as Coal Seam Gas (CSG), over 5 000 CBM wells have
been drilled in Queensland in the last few years and the industry is aggressively
expanding into New South Wales.
In the UK CBM is more advanced than Shale Gas and full-scale production may begin
soon.
Over 44 percent of wells are leaking in an Australian gas field overseen by UK Treasury
director Baroness Hogg.
Kyk weer!
Aerial view of the Jonah natural gas field, upper Green
River Valley, Wyoming, 2001 - SkyTruth
Simply pumping depends mostly on sufficient saturation:
That is the percentage of sediment pore space in the source rock occupied
by gas hydrate.
1. What about contamination on top and beneath the surface by pumping?
2. What about cross-contamination between aquifers?
3. What about leaking gas and air contamination?
What if the gasbearing coal layer is too consolidated and unpermeable and
will require gas flow to be stimulated?
1. One possibility to achieve this is to FRACK.
2. The other option is CAVITATION.
What if the presence of Uranium and Radon endangers safe extraction,
production and use?
What if safe separation of the Uranium/Radon complex from the
Methane/coal is not economically viable at production scale ?
Finally ...
A.
B.
Will the Springbok Flats
survive
exploration for CBM
and the production of it?
Will the people of the Springbok
Flats allow it?
We have the Constitutional right to oppose it!
We no longer have to practise this in a vacuum because
The Bill of Rights of our Constitution since 1996
provides as follows in regard to the environment:
24 Everyone has the right
a. to an environment that is not harmful to their health or well-being; and
b. to have the environment protected, for the benefit of present and
future generations, through reasonable legislative and other measures
that
i. prevent pollution and ecological degradation;
ii. promote conservation; and
iii. secure ecologically sustainable development and use of natural
resources while promoting justifiable economic and social
development.
Mag jy hierdie verruil ...
of hierdie ...
of hierdie ...
vir dit?
http://beyondeconomics.files.wordpress.com/2013/01/fracking-field-4.jpg
Kom help dat ons kan saambou
aan die insig om ons gebied gesond te hou
en om ons te help om vas te staan
om CBM-produksie en ander myne
in hierdie gebied af te wend.
By understanding how to keep our area
healthy we will gain the knowledge
to remain steadfast
against wilful destruction.
En wat nou as die oopgroef Uraan- en
Steenkoolproduksie voortgaan?
Nog erger as met CBM ...
... is hoe die oopgroefmyne sal lyk.
Hier is een van die groot getal
oopgroefmyne
by Middelburg/Witbank!
Tot siens? Se voet!
Download

Coal Bed Methane - Waterberg Conservation Forum