Reservoirs of Ancient Lava Shaped Earth

Geological history has periodically featured giant lava eruptions that coat large swaths of land or ocean floor with basaltic lava, which hardens into rock formations called flood basalt. New research from Matthew Jackson and Richard Carlson proposes that the remnants of six of the largest volcanic events of the past 250 million years contain traces of the ancient Earth's primitive mantle -- which existed before the largely differentiated mantle of today -- offering clues to the geochemical history of the planet.

Scientists recently discovered that an area in northern Canada and Greenland composed of flood basalt contains traces of ancient Earth's primitive mantle. Carlson and Jackson's research expanded these findings, in order to determine if other large volcanic rock deposits also derive from primitive sources.

Information about the primitive mantle reservoir -- which came into existence after Earth's core formed but before Earth's outer rocky shell differentiated into crust and depleted mantle -- would teach scientists about the geochemistry of early Earth and how our planet arrived at its present state.

Until recently, scientists believed that Earth's primitive mantle, such as the remnants found in northern Canada and Greenland, originated from a type of meteorite called carbonaceous chondrites. But comparisons of isotopes of the element neodymium between samples from Earth and samples from chondrites didn't produce the expected results, which suggested that modern mantle reservoirs may have evolved from something different.

Carlson, of Carnegie's Department of Terrestrial Magnetism, and Jackson, a former Carnegie fellow now at Boston University, examined the isotopic characteristics of flood basalts to determine whether they were created by a primitive mantle source, even if it wasn't a chondritic one.

They used geochemical techniques based on isotopes of neodymium and lead to compare basalts from the previously discovered 62-million-year-old primitive mantle source in northern Canada's Baffin Island and West Greenland to basalts from the South Pacific's Ontong-Java Plateau, which formed in the largest volcanic event in geologic history. They discovered minor differences in the isotopic compositions of the two basaltic provinces, but not beyond what could be expected in a primitive reservoir.

They compared these findings to basalts from four other large accumulations of lava-formed rocks in Botswana, Russia, India, and the Indian Ocean, and determined that lavas that have interacted with continental crust the least (and are thus less contaminated) have neodymium and lead isotopic compositions similar to an early-formed primitive mantle composition.

The presence of these early-earth signatures in the six flood basalts suggests that a significant fraction of the world's largest volcanic events originate from a modern mantle source that is similar to the primitive reservoir discovered in Baffin Island and West Greenland. This primitive mantle is hotter, due to a higher concentration of radioactive elements, and more easily melted than other mantle reservoirs. As a result, it could be more likely to generate the eruptions that form flood basalts.

UK airports flight information: Volcanic ash latest

UK airports flight information: Volcanic ash latest

Tuesday, 24 May 2011

Passengers wait with their luggage at Glasgow Airport (PA)

The European air traffic agency Eurocontrol said that between 200 and 250 flights have been cancelled in Europe.

 The disruption is expected to spread to some northern England airports later today.

The eruption of the Grimsvotn volcano has already led to airlines cancelling a number of flights to and from Irish and Scottish airports.

 Shortly after 9.30am today, air traffic control company Nats said "an area of volcanic ash" was forecast to affect some parts of the UK between 1pm and 7pm today.

 Nats said airports remained open but that services from Londonderry, Glasgow, Edinburgh, Prestwick, Newcastle, Carlisle, Durham Tees Valley and Cumbernauld airports may be affected.

Nats said passengers should check with their airline before travelling to these airports.

The airports listed by Nats could all possibly experience high- level densities of ash.
Earlier Nats had said air services at Aberdeen, Inverness, Benbecula, Barra and Tiree airports could be affected until 1pm. The latest bulletin from the company suggested that these airports might be free of ash later today.

In the meantime, airlines have already axed many flights to and from Scotland, with British Airways not operating any flights between London and Scotland before 2pm.
Scots regional airline Loganair scrapped 38 flights and Irish carrier Aer Lingus said it had cancelled 12 flights to and from Glasgow, Aberdeen and Edinburgh.
British Airways announced that it would not operate any flights between London and Scotland before 2pm.
EasyJet also cancelled its flights from Glasgow until lunchtime.
At Glasgow today, most passengers whose flights had already been cancelled did not make their way to the airport.
Passengers with holiday companies Thomson and Thomas Cook were waiting for buses to take them to Manchester to pick up later flights.

The airport's cafes were packed and people sat on their suitcases or tried to catch up on sleep as they waited for news.

Guy McKinven, from the Clyde Valley area, was travelling with easyJet to Stansted to spend a week with his grandmother.
He said: "You see people shouting and getting upset, but there's nothing you can do.
"It is frustrating, but that's just the situation. EasyJet have been helpful and have told me I can have a refund for my flight.
Despite the flight cancellations today, there were hopes that the latest crisis would not have the same devastating impact as last year's Icelandic volcanic eruption which saw UK airspace shut down and thousands of air services axed.

Transport Secretary Philip Hammond said: "There is some early indication that the scale and power of the eruption might be subsiding a little bit.
"Perhaps it's a little bit too early to be absolutely sure about that, but clearly that's the most important thing. If the ash stops belching out of the volcano then, after a few days, the problem will have cleared, so that's one of the factors.
"The other is the wind speed and direction. At the moment the weather patterns are very volatile which is what is making it quite difficult, unlike last year, to predict where the ash will go."
He added that the public should be assured that airlines would only operate when it was safe to do so.
Ryanair said it carried out a one hour flight 41,000ft over Scotland this morning in the so-called "red zone" of the ash cloud from Glasgow Prestwick to Inverness, on to Aberdeen and then south to Edinburgh.

Aviation chiefs have deemed Scottish airspace "high ash concentration".

Ryanair said there was no visible volcanic ash cloud or any other presence of ash and post flight inspections revealed no evidence of ash on the airframe, wings or engines.

The low-cost carrier claimed the red zone was non-existent, mythical and a misguided invention by the UK Met Office and the Civil Aviation Authority (CAA).

Ryanair said it has written confirmation from both its airframe and engine manufacturers that it is safe to operate in the area.

"This morning's verification flight has demonstrated that the UK Met Office's 'red zone' forecasts are totally unreliable and unsupported by any evidence of volcanic ash concentrations whatsoever," Ryanair said.

Read more: http://www.belfasttelegraph.co.uk/news/local-national/northern-ireland/uk-airports-flight-information-volcanic-ash-latest-16003692.html#ixzz1TAcgSE19

supervisor Geologist Questions

Geology Questions?

BASIC CONCEPTS OF GEOLOGY

1. How long ago was the oil being extracted today formed?

The oil was roughly formed between 30 to 500 million years ago


2. Where do you find oil or gas in rock underground?


We find them in pore or fracture of rocks


3. What are the common reservoir rocks?


There are sandstone, limestone and dolomite


4. What sort of rocks are they?


They are mostly sedimentary rocks


5. What is meant by a trap?


A trap is a underground formation which prevent the escape of oil and gas contained in reservoir rock.


6. What is a cap rock?


Cap rock is non-porosity and impermeable to the fluids bellow


7. Do you think overburden pressure can force the reservoir fluids through the cap rock and up to surface if a hole is drilled through the cap rock?


Yes


8. How do oilmen know where to drill?


Generally speaking, that is the job for the petroleum geologist.


9. how can petroleum geologist locate the position where oilmen are to drill?


Petroleum geologist can use the result of seismic surveys (or even aerial surveys) to get information about rock features beneath the surface


10 when and how was the earth originated?


The earth is though to have originated some four to five billion years ago by condensing out of a cloud of cosmic dust.


11.what is the origin of igneous rocks?


Igneous rock is solidified from molten form called magma.(molten melt)


12.how many kinds of rocks have been considered so far?


Three kinds


13.what are they ?


they are igneous rock, sedimentary rock and metamorphic rock.


14.if metamorphic rocks are subjected to even more heat, they may be melted and become magma rocks, do you agree?


Yes ,I agree. (ignore and igneous inflame)


15.among igneous rocks, metamorphic rocks and sedimentary rocks, which one is more important to petroleum geology?


Of course,the sedimentary rock is more important than the rest.


16.why?


because most oil and gas accumulations occurs in sedimentary rock.


phenomenon appearance phenomena


17.where can we see some samples originally deposited in an ancient sea?


Some remains of marish shells can be found in some hightest mountains and in deepest oil wells.


18.what is the most common kind of deformation?


The most common kind of deformation is the buckling of the layers into a fold.


.are folds the most common structure in mountain chains


yes ,folds are the most common structure both in present and former mountain chains.


20.what are anticlines?


Anticlines are upfolds or arches structure of the mountain chains.


21.and synclines?


Downfolds or troughs are synclines.


22．Folds, usually,have only one form, is that right?


No. folds have many forms.


23.folds are often symmetrical, are not they?


yes and no. they may be symmetrical or asymmetrical


24.how do you describe faults?


Faults are described according to their present attitude by various names.


25.how many kinds of faults are classified?


There are four kinds of faults.


26.what are they ?


they are normal,reverse,thrust and lateral.


27.what are rotational faults and upthrusts?


Rotational faults and upthrusts are variations of normal and reverse faulting.


28.how many kinds of oil seeps are there in petroleum geology?


There are two general kinds.


29.what are these two kinds of oil seeps?


Seepage up --dip and seepage along fractures.


30.are there any other geophysical methods used to find suitable structure for petroleum accumulation?


Yes ,there are.


31.could you tell me what these methods are?


We can find favorable structures for petroleum accumulation using gravimeter and magnetometer .


32.what is porosity?


Porosity is a measure of the pore space in the body of reservoir rocks, usually expressed as a percent of a void space per unit volume of rock.


33.what is permeability?


Permeability is a measure of ease with which a fluid flows through the connected pore spaces of a reservoir rock.


34. is it important to predict sand trends in exploiting sandstone reservoirs?


Yes ,but not only the prediction of sand trends but also the prediction of pore space distribution.


35．What is needed to get a petroleum accumulation ?


there are three points in dealing with the question.


36.what is the first point,please?


Firstly ,there must be a source of oil and gas.


37.and your second point?


Secondly,the existence of a porous bed which is permeable enough to permit the oil and gas to flow through it the reservoir rock.


38.and the last one .


a trap ,which is a barrier to flow fluid so that accumulation can occur against it


39.where did oil and gas originated ?


oil and gas originated from decayed organic matter in sedimentary rock.


40．What does the word “migration”mean in petroleum geology?


After generation ，the dispersed hydrocarbons in the fine grained source rocks must be concentrated by migration to a reservoir。Such a process is called migration 。


41．How are the driving forces behind migration ？


the driving forces behind migration are provided by the weight of the overlying rocks，circulating of groung water and gravity。


42．What are those forces behind migration?


The driving forces are the forces necessary to expel the hydrocarbons and to move them through the more porousbeds or fractures to regions of lower pressure.


43．Do you think gravity plays some part in the migration ？


yes ，gravity plays a role of separating gas ，oil and water。


44．What about the distribution of fluids in a reservoir rock？


The distribution of fluids deponds on their densities and on the capillary properties of the rocks。


45．If a reservoir rock contains uniform pores，and if the pore are evenly distributed，what will the distribution of fluids be like in a trap， then？


In this case ，there will be three zones of fluids in the trap。


46．What are the three zones in a trap ，please？


An upper zone( or gas cap) ,a middle zone and a lower zone .


47．What are contained in the three zones respectively？


The rock pores in the upper zone are filled mainly by gas.


48．And the middle zone and the bottom zone？


The middle is filled mainly by oil and gas in solution and the lower water


49．Is there any water in the middle zone？


A certain amount of water always occurs together with oil in middle zone。


50．What is the usual proportion of water to oil in the middle zone？


The proportion of water to oil is usually from 10 to 30 percent。


51．Does water occur in the gas cap?


Yes ,it does.but the proportion of water to gas is frequently lower than the proportion of water to oil.


52．Is there a special name for the water found in the oil and gas zones？


Yes，there is。It is called “interstitial water”or“connate”


53．Does the crude oil in a trap contain natural gas in solution under pressure?


Yes ,it does. It is the local pressure and temperature conditions that keep the gas in solution with the oil.


54．How does the natural gas come from crude oil？


It is quite simple 。（quite） simple.when the crude oil rises to the surface ,the pressure drops. And-----


55．Oh ,I see,as the crude oil rises to the surface the pressure has dropped enough, the gas comes out of solution?.


Yes ，you are right。


56．Why are gas wells and most wells initially flowing well？


The basic production mechanism in naturally flowing wells is the result of pressure differences。


57．If the bottom hole pressure resulting from the hydrostatic head is lower than formation pressure the oil will move through the pores of the reservoir rock and out into the bottom of well bore ，is that right？


Yes ，you are right。


58．How many factors affect the flow rate of reservoir crude？


Four factors。


59. what are the four factors？


Bottom-hole pressure，formation pressure，rock permeabiliy，and the viscosity of the oil。


60．What kind of reservoir has the hightest permeabilities of all?


Of course the fracture d reservoir。


61．What is a wet gas？


If natural gas contains a relatively large quantity of the other heavier hydrocabons，it is called a wet gas。


62．Is there any other name for natural gas？


Yes ，there is 。


63．What is it？then？


it is called a dry gas。


64．What comes to the top of a well together natural gas？


Lighter liquid hydrocabons，and wanter。


65．In what technical terms that an oilman would use？


In suspension。






V．2 SAMPLING


1． What is sampling ？


Sampling is collecting cuttings at a certain place on a rig。


2． What are the cuttings?


Cuttings are chips of rock cut from the formation by the bit


3． How do the cuttings come out of the bore hole？


They are carried to the surface by the mud circulating up the annulus。


4． Where do you collect cuttings on the rig？


We always collect the cuttings from the shale shaker screen。


5． Whose job is it to collect the cuttings?


Of course ,sample catcher is.but during the initial period of drilling,the mud logger often gives a hand.


6. how does he know when to collect the cuttings?


The sample catcher is told for the collection each time by a mud logger.


7. and how does the mud logger know when to collect the cuttings?


He can respond to the buzzer signal given by the on-line system or he can observe the regular depth interval shown at a panel.


8． is that all?


Of course not。It also depends on the lag time of the cutting transit in the annulus。


9． By the way，what does a sample catcher collect the cuttings with？


Well，he offen collect cuttings with trowel。


10． How much cuttings does the sample catcher collect each time？


That deponds。Normally 500 gram is enough。


11． What should he pay attention to while collecting the cuttings?


To ensure that a representative sample is taken with minimum caving.


12.what is the next step after the collection ?


washing the collected cuttings.


13.why do you have to wash the cuttings?


In order to have a better look at them under the microscope.


14. is it difficult to wash the the cuttings.


Yes and no .it all depends on the rock areas that are drilled.


15.what do you mean by this ?


I mean that the cuttings drilled in hard rock areas,usually quite easily cleaned,but it is more difficult for those in areas and zones of loose sands and shales. tight


16.by the way ,how do you often wash and clean the cuttings?


We wash the cuttings in a sieve-stack..


17.why do you clean the cuttings in sieve-stack?


Because we want to collect the required grain size of cuttings.


18.then what are you going to do with these washed cuttings?


Some of them shall go for examination under the microscope ,and the rest shall be dried in an oven. furnace

What is mean groundwater

What is groundwater?

When rain falls to the ground, the water does not stop moving. Some of it flows along the surface to streams or lakes, some of it is used by plants, some evaporates and returns to the atmosphere, and some sinks into the ground. Imagine pouring a glass of water onto a pile of sand. Where does the water go? The water moves into the spaces between the particles of sand.
Groundwater is water that is found underground in the cracks and spaces in soil, sand and rock. Groundwater is stored in--and moves slowly through--layers of soil, sand and rocks called aquifers. Aquifers typically consist of gravel, sand, sandstone, or fractured rock, like limestone. These materials are permeable because they have large connected spaces that allow water to flow through. The speed at which groundwater flows depends on the size of the spaces in the soil or rock and how well the spaces are connected.





The area where water fills the aquifer is called the saturated zone (or saturation zone). The top of this zone is called the water table. The water table may be located only a foot below the ground’s surface or it can sit hundreds of feet down.
Groundwater can be found almost everywhere. The water table may be deep or shallow; and may rise or fall depending on many factors. Heavy rains or melting snow may cause the water table to rise, or heavy pumping of groundwater supplies may cause the water table to fall.
Water in aquifers is brought to the surface naturally through a spring or can be discharged into lakes and streams. Groundwater can also be extracted through a well drilled into the aquifer. A well is a pipe in the ground that fills with groundwater. This water can be brought to the surface by a pump. Shallow wells may go dry if the water table falls below the bottom of the well. Some wells, called artesian wells, do not need a pump because of natural pressures that force the water up and out of the well.
Groundwater supplies are replenished, or recharged, by rain and snow melt. In some areas of the world, people face serious water shortages because groundwater is used faster than it is naturally replenished. In other areas groundwater is polluted by human activities.
In areas where material above the aquifer is permeable, pollutants can readily sink into groundwater supplies. Groundwater can be polluted by landfills, septic tanks, leaky underground gas tanks, and from overuse of fertilizers and pesticides. If groundwater becomes polluted, it will no longer be safe to drink.
Groundwater is used for drinking water by more than 50 percent of the people in the United States, including almost everyone who lives in rural areas. The largest use for groundwater is to irrigate crops.
It is important for all of us to learn to protect our groundwater because of its importance as a source of water for drinking and irrigation.