Fracking - moved from another thread

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9 years 3 months ago #34674 by Organix

Blueberry;457527 wrote: well, Organix, i don't know about you, but i would HATE living next door to a forrest of drill rigs or fracking sites[B)], and the possibility of that happening if you own land in Taranaki is getting more and more likely.

To each their own but a wellsite takes only a few months to drill and hook up, and it then becomes just a few innocuous and silent pipes sticking out of the ground. Dairy effluent, water requirements and fertiliser application are far greater and more permanent blights and dairying doesn't have the RMA restrictions that the energy sector does. Incidentally drill rigs don't come in "forests" - if they need to access several reservoirs they drill multiple wells from the same location.

And there is no point in getting excited about fracking. Under Taranaki geological conditions there is about 2km of rock between the hydrocarbon reservoirs (where the fracturing is carried out) and far shallower potable water aquifers so there is virtually nil chance of the the two coming into contact, but the raving anti-fracking brigade refuse to absorb that basic logic.

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9 years 3 months ago #456393 by Blueberry
'I'm no more evil than the other, so I must be good?"

I don't particularly care what name you want to put on it, Organix, I simply don't want any of that near me if I can help it. I'm not alone in that view. Still find it interesting that it's mostly people deriving their income directly or indirectly from the Oil and Gas business who are so vociferous about the "good" it supposedly does to our communities and how 'badly" some other industry has been behaving.

Comparing the nefarious practices from one industry to the destruction wrecked of another is of no value nor help and does not justify the destruction of the environment - no matter how many families it feeds in the short term.

[;)] Blueberry
treading lightly on mother earth

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9 years 2 months ago #457062 by igor
I'm sure that all those people who complain about the practices of the oil and gas industry still expect to be able to buy fuel for their vehicles.

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9 years 2 months ago #457152 by wandering free

Organix;457583 wrote: and far shallower potable water aquifers so there is virtually nil chance of the the two coming into contact, but the raving anti-fracking brigade refuse to absorb that basic logic.

When they frack don't they get 10% back-flow from the wells of the fracturing fluid, how do they store it or dispose of it. this is what Wikipedia says:- Fracturing equipment operates over a range of pressures and injection rates, and can reach up to 100 megapascals (15,000 psi) and 265 litres per second (9.4 cu ft/s) (100 barrels per minute).

Just me and the cat now, on 2 acres of fruit and veg + hazel nuts, macadamia, chestnuts and walnuts,
www.youtube.com/user/bandjsellars?feature=mhee

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9 years 2 months ago #457169 by Organix

wandering free;458423 wrote: When they frack don't they get 10% back-flow from the wells of the fracturing fluid, how do they store it or dispose of it. this is what Wikipedia says:- Fracturing equipment operates over a range of pressures and injection rates, and can reach up to 100 megapascals (15,000 psi) and 265 litres per second (9.4 cu ft/s) (100 barrels per minute).

Petroleum geology is a highly complex and continually developing field but hopefully I can outline a few of the basics.

Oil reservoirs exist where a fault line (as in the diagram contained in the above link), or other geological structure such as a domed rock layer has acted to trap hydrocarbons, thus accumulating them rather than them dissipating into surrounding strata. Such hyrocarbons and associated other fluids are held within rock layers, which are obviously less dense than the overlying 'cap' layer/s.

Once a likely reservoir formation has been located by seismic survey or other exploration methods a well is drilled into this zone and based on core samples and pressures encountered a decision to develop and 'flow' the well is made. In many cases factors such as previously undetected fissures in the cap rock can result in the hydrocarbons having been dissipated and lost over time rather than being trapped, and the well will be deemed 'dry'.

Where a hydrocarbon rich reservoir is found its upper and lower boundaries are identified. The steel pipe that makes up the finished oil/gas well will be 'perforated' by way of explosives at an planned depth within the identified zone so that the oil (or gas) can then flow from the reservoir rock, through these exploded perforations, into the well and up to the surface. These fluids are driven by the pressures within the reservoir which can commonly be in the region of 2,000 - 5,000 psi, and often much higher.

The fluids within the reservoir consist of an upper layer of natural gas, a mid layer of crude oil or 'condensate' (thin liquids much like kerosene) and an underlying layer of salty brine. All of these fluids are contained in tiny holes in the reservoir rock. The productive capacity of a reservoir is heavily dependant on the porosity of the rock (i.e. the amount of holes as a percentage of the rock volume) and the permeability (i.e. the interconnectedness of the holes).

Following the drilling of a successful well a period of 'testing' is usually carried out during which time the flow will be stopped and started for various periods with flow volumes, and pressures both on the surface and in the reservoir being monitored. The rate of pressure drop during flow, and the rate at which it recovers during non flow will indicate the potential size and flow rate of the well. As this testing requires unrestricted flow and the fluids released initially contain drilling debris it is usual to flow the well to flare during this time. Flaring is also the safest and most practical way to deal with such released gas and other flammable fluids. Any accompanying (unburnt) contaminants are captured in a specially constructed and sealed pit under the flare for subsequent removal and safe disposal (e.g. see 'reinjection' below).

To gain the best production from an oil reservoir the well is perforated within the oil zone. If perforated too high the gas will be released prematurely which will reduce the productive life expectancy of the well as this gas is what provides the pressure to push the oil to the surface. Perforating too low will result in an excessive amount of water being present in the well flow which as well as being economically worthless must also be dealt with, typically by way of being reinjected into an unproductive well under pressure.

All production wells will of course lose pressure over their productive life due to the draw off of well fluids. This can often occur when as little as 20-30% of the oil present has been extracted by 'primary' extraction methods. At this point a variety of 'secondary' extraction methods are available. The most obvious is to pump oil to the surface but this is only possible/practical in relatively shallow reservoir situations such as in the oilfields of the southern US where hundreds of 'nodding neddy' beam pumps are used.

For deeper reservoirs methods including gas reinjection are used which aim to repressurize the reservoir in order to push more oil to the surface. This has been a common strategy in the Taranaki oil industry where reservoir formations are typically 2 km or deeper.

Other strategies used to increase the volume extracted from a reservoir both in the short term and over the length of a well's life is to modify the reservoir's geological characteristics. This aims to increase the permeability of the reservoir so that the fluids flow more easily out of the rock and into the well stem (pipe). This can be done by injecting acids into the well which then penetrate into the fissures in the rock thus enlarging the 'capillaries' through which the oil can flow. This result can also be gained by forcing fluids containing chemicals and small particles into these same capillaries. This enlarges the capillaries by physical hydraulic force and the particles act to hold these fissures open once the oil/gas flow is resumed. This technique is known as hydraulic fracturing or 'fracking', and has been used in the NZ oil industry over the past 20 years or more.

Following a fracking procedure a quantity of debris is understandably expelled from the well which is dealt with by way of capture into a flare pit or similar as explained above.

The concerns from opponents to fracking regarding gas/oil/fracking fluid contamination of potable aquifers are virtually groundless under the conditions present in Taranaki as the hydrocarbon reservoir and aquifer stratas are separated by 2 km or so of rock at least. The dramatic 'flaming taps' portrayed in the video Gaslands can only usually occur in areas where oil reservoirs exist at relatively shallow depths.

Additionally the intention is to increase flow from the reservoir toward the well by limiting fracturing to within the oil bearing zone of the reservoir. If fracturing occurs beyond this zone it would prove very counterproductive as it would be contributing to the rapid demise of the well's economic life.

The 'escape' of drill fluids, including fracking fluids, to the environment by way of 'leaks' in the well pipe is also highly unlikely as due to the extremely high pressures present such a 'leak' would very quickly (i.e. immediately) become apparent with potentially explosive results.

Apologies for hijacking this thread but hopefully educational for many :)

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9 years 2 months ago #457205 by Hawkspur
Thanks for that information, Organix.
You succinctly explained something I had been meaning to read a bit about, so now I don't have to go wandering the internet (no-effort answers are the best) - until I come up with some more questions that is...[;)]

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9 years 2 months ago #457232 by wandering free

Hawkspur;458479 wrote: Thanks for that information, Organix.
You succinctly explained something I had been meaning to read a bit about, so now I don't have to go wandering the internet (no-effort answers are the best) - until I come up with some more questions that is...[;)]

Yes I go along with that, Thanks organix :) , all my reading had been on the US tight oil, and nothing like what is happening in Taranaki, I wonder what it's EROI is when you have to drill that deep though. just had to through that quesion in, I'm a stirring old bugger I know,[}:)]

Just me and the cat now, on 2 acres of fruit and veg + hazel nuts, macadamia, chestnuts and walnuts,
www.youtube.com/user/bandjsellars?feature=mhee

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9 years 2 months ago #457249 by Organix

wandering free;458507 wrote: Yes I go along with that, Thanks organix :) , all my reading had been on the US tight oil, and nothing like what is happening in Taranaki, I wonder what it's EROI is when you have to drill that deep though. just had to through that quesion in, I'm a stirring old bugger I know,[}:)]

2 kilometres is far from deep. Record depth wells exceeding 12,000m have recently been drilled on Sakhalin Island , north of Japan.

The costs of drilling oil wells , both in terms of monetary and energy return, escalate significantly due to not only depth but also when drilled offshore, in adverse climates (e.g. arctic), and if technically complex methods such as directional drilling are used (i.e. deviating from vertical to as much as horizontal - see above link).

Remember though that these costs will ultimately be paid for by the consumer, and as oil prices rise and technology develops the viability of wells (or regions) that are initially deemed uneconomical later become paying propositions. We as a species are addicted to this 'cheap' energy source which is essentially sunlight that was absorbed by plants living millions of years ago which were then fossilized deep underground. Watch HOME (93 minutes of brilliant HD movie) to see where I'm coming from on this.

So the reality of peak oil is that it will not be a case of the world waking up one morning to no more oil, but will be of the costs of finding, drilling, extracting and processing ever more scarce reserves in increasingly difficult locations eventually putting this energy source out of reach of we who consume it. The current world recession combined with advances in fracking techniques have given peak oil a breather, for now, but it has far from gone.

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NZ & AU distributor of Eco Wood Treatment stains and Bambu Dru bamboo fabrics and clothing

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9 years 2 months ago #457256 by belinda_h
Could we maybe move the fracking debate to another thread? This is supposed to be about organising a road trip. Please?

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9 years 2 months ago #457270 by LongRidge
You might be correct belinda, but if you happen to be concerned about fracking then this discussion might get a buyer less concerned about an region where fracking occurs. Personally, I'm hugely more concerned about one of the caldera exploding, and Taupo is the most overdue of the 9 recognised calderas in the world. When the last decent sized volcano exploded (Krakatoa), the sound could be heard 10000km away, and the dust caused all sorts of problems. When Taupo goes, I hope the wind is not a northerly!

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9 years 2 months ago #457382 by wandering free
I think discussing fracking might be interesting to some one from Canada, I for one wouldn't want to live near them, especially now oil prices are rising and the development of marginal fields becomes profitable, NZ's oil fields are in decline and it is only with fracking that the last dregs are recovered, even then on the world stage we have scarcely 3 months worth of reserves. just been reading the German military assessment of world oil, http://www.energybulletin.net/sites/default/files/Peak%20Oil_Study%20EN.pdf
from 2.1 it gets interesting.

Just me and the cat now, on 2 acres of fruit and veg + hazel nuts, macadamia, chestnuts and walnuts,
www.youtube.com/user/bandjsellars?feature=mhee

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