Monday, May 30, 2011

What The Last Man On The Moon Picked Up

Harrison Schmitt was the last man on the moon and he collected soil samples.  These languished in a drawer for 40 years. Recently Erik Hauri,  a staff scientist in geochemistry at the Carnegie Institute for Science and his student Tom Weinreich from Brown University examined these samples and found that tiny moon crystals contained inclusions of magma. Using an ion microprobe they were able to measure the amount of water in these magma inclusions and make an estimate of how much water may be present in the interior of the moon - trapped in such crystals.

The answer is a lot... about the amount of water in the Mediterranean sea... but it is dispersed and there is no efficient way to collect it in useful amounts.  According to Prof. Hauri the water in the lunar magma inclusions is in amounts similar to water expected in the Earth's upper mantle.

On Science Friday Ira Flatow discusses this discovery with Erik Hauri and what it means for our understanding of the evolution of the earth and moon system and specifically the implications for the origin of water on early earth and the moon.

The presence of water ice in craters near the north and south poles of the moon was known from recent remote sensing sorties by spacecraft from U.S  and India. Erik Hauri speculates on how this water in the lunar craters came to be.. is it of very ancient volcanic origin, sourced ultimately from the magma he measured?.. that water may be billions of years old since volcanism was present only in the very early history of the moon.. or is that water a later addition, plastered on to the surface of the moon by comets and meteorites?..

There is still much to learn about lunar evolution.

Listen / Transcript

Monday, May 23, 2011

Couple Of Articles On Earthquakes

Not all writing by journalists on earthquakes and earthquake prediction border on sensationalism and unsupported speculation. Here is a sensible one by Christina Reed in Discover Magazine...

Also over at Ars Technica John Timmer summarizes the finding of three studies aimed at understanding the mechanics of the recent Japan earthquake, now officially known as the Tohoku-Oki quake.

Monday, May 16, 2011

India Basin-Wise Shale Gas Estimates

Sometime back I had posted a graphic of Indian sedimentary basins and the potential of shale gas from these basins. Currently India has reserves of about 38 trillion cubic feet (Tcf) of conventional natural gas i.e. gas stored in pore spaces of coarser permeable sedimentary rocks like sandstones.

I had mentioned that shale gas i.e. natural gas trapped in very fine grained, impermeable shales might add substantially to the existing conventional natural gas reserves. I did not have any numbers to put out at that time.

Now the U.S Energy Information Administration (EIA) has come out with a report (51 mb) on global shale gas potential that includes some Indian sedimentary basins as well. The report has been prepared for the EIA by Advanced Resources International, a company based in Virginia, U.S.

About 70 shale formations from 48 basins in 32 countries were studied. Here is the global summary in terms of shale gas potential. The report only partially estimates shale gas resources since it excludes Russia and the Middle East. It also excludes offshore basins and many other onshore basins for which data is not available:

Although the shale gas resource estimates will likely change over time as additional information becomes available, the report shows that the international shale gas resource base is vast. The initial estimate of technically recoverable shale gas resources in the 32 countries examined is 5,760 trillion, cubic feet, as shown in Table 1. Adding the U.S. estimate of the shale gas technically recoverable resources of 862 trillion cubic feet results in a total shale resource base estimate of 6,622 trillion cubic feet for the United States and the other 32 countries assessed. To put this shale gas resource estimate in some perspective, world proven reserves of natural gas as of January 1, 2010 are about 6,609 trillion cubic feet, and world technically recoverable gas resources are roughly 16,000 trillion cubic feet, largely excluding shale gas. Thus, adding the identified shale gas resources to other gas resources increases total world technically recoverable gas resources by over 40 percent to 22,600 trillion cubic feet.

Global consumption of natural gas was estimated to be about 100 Tcf in 2009 and is projected to increase to about 156 Tcf by 2035.

Do read the summary and the report (51 mb) to get an idea about the methodology for estimating shale gas resources. 

For India, data adequate enough to generate estimates of shale gas was available from 4 sedimentary basins. These were from the Cambay Basin, the Krishna Godavari Basin, the Cauvery Basin and the Damodar Valley Basin. These basins are estimated to contain about 63 Tcf of recoverable shale gas.

There are many other sedimentary basins which remain relatively unexplored for their shale gas potential.

Image below shows the assessed sedimentary basins along with other basins which are though to contain shale gas but for which adequate data is not yet available.

Below is a basin-wise breakdown of the shale gas estimates along with graphics of the basin structure and prospective blocks within the basins.

Cambay Basin:

This is an elongate intra-cratonic rift basin of late Cretaceous-Cenozoic age situated in western Indian state of Gujarat. The formation of interest is the Palaeocene-Eocene Cambay black shale. Technically recoverable shale gas is estimated to be about 20 Tcf.

Krishna Godavari Basin:

A Late Permian to Tertiary age basin in eastern India consisting of a series of horst and graben. The prospective formation is the Permian age Kommugudem shale. Technically recoverable resources are estimated to be about 27 Tcf.

Cauvery Basin:

The Cretaceous-Cenozoic Cauvery basin in south eastern India is another basin with horst and graben structures and prospective shales. The formations of interest are the early Cretaceous Andimadam Formation and the Sattapadi shale. Technically recoverable resources are about 9 Tcf.

Damodar Valley Basin:

This basin is part of the "Gondwana" basins of India characterized by their mostly non-marine sedimentary fill and narrow graben structures. Although filled with mostly Late Permian to Triassic terrestrial sediment, there is a significant thickness of a marine shale known as the Barren measures, so called as it is barren of coal. The technically recoverable resources from this shale are estimated to be 7 Tcf.

Below is a table summarizing the geological and shale gas attributes of the basins of interest.

As the report makes clear, these are initial estimates (not proven reserves) based on available data on shale formations from basins that already have seen substantial exploration for oil and conventional natural gas. As more focused exploration for shale gas continues from these basins and as more basins are explored these estimates of shale gas resources will likely change.

Update [ May 17 ]: [ Just a quick clarification on terminology. In the table above three estimates of gas are given. GIP is Gas in Place and it refers to the total gas content of the shale formation as estimated from geological attributes. Risked GIP is a fraction of GIP after applying certain success factors i.e. using information available of the productivity of the formation and other factors that might limit its development. Finally, Risked Recoverable is the fraction of Risked GIP that can be technically recovered. That is the amount - 63 Tcf- I have used in this post.

There are reports in the media claiming for example that shale gas in India has been estimated to be about 600 - 2000 Tcf. These refer to Gas in Place estimates and are comparable to the GIP estimates in the EIA report. They are sometimes improperly referred to as reserves (amount of resource that can be exploited economically at any given time). These large amounts mentioned in some media reports are not proven reserves but an estimate of the total gas content stored in the formation. Out of that only a fraction will be technically recoverable.]

India produced about 1.4 Tcf in 2009 and consumed about 1.8 Tcf.  These shale gas resources as they are realized will add significantly to India's hydrocarbon reserves.

Some broad issues to think about:

1) Will a shale gas policy allowing for exploration and exploitation be put in place quickly?

2) Will concerns about leakage of fracking fluids and methane into groundwater be addressed thoroughly and transparently.

3) Besides contamination of groundwater, there is also a concern of water usage. Wells drilled into shale require large amounts of water to be pumped in during the process of fracking i.e hydraulic fracturing of the rock.  How will conflicts of water use with farmers and affected communities be resolved?

Update Jan 5 2012: In a recent assessment (USGS Fact Sheet India Shale Gas 2011) of the Cambay, Krishna Godavari and Cauvery provinces of India, the United States Geological Survey has downgraded shale gas resources from 63 tcf estimated by the Energy Information Agency to 6.1 tcf. Downgrading shale gas resource estimates is not unique to India. Revisions are going on all over the world and is probably due to the observation that production from shale gas wells falls significantly after the first year or so of extraction. So their performance over the long term may not be able to match up the initial surge.  For example, the prolific Marcellus Shale from eastern U.S initially estimated to contain 410 tcf of gas again estimated by the EIA has been downgraded to contain about 84 tcf of technically recoverable gas by the USGS.

The India revision is analogue data and was developed using estimates of ultimate well recovery and success ratios from various U.S. data. This figure might itself be open for revision as more focused exploration is undertaken in these various basins.

Wednesday, May 11, 2011

Darwin: His Illnesses Finally Diagnosed?

After his voyage on the H.M.S Beagle 1831 - 1836, Charles Darwin suffered for ill health for the rest of his life. The reasons given were parasitic infections and stress. At a recent Historical Clinicopathological Conference organized by The University of Maryland School of Medicine in Baltimore and the Veterans Administration Maryland Health Care System, diagnosticians narrowed the field to three ailments: chronic vomiting syndrome, Chagas disease and Helicobacter pylori, or peptic ulcers.

I was familiar with Chagas disease being one of the suspects. Long back I saw a medical forensic documentary on Darwin where Chagas disease was considered the best fit for his symptoms. There was even an attempt to search for the parasite by trying to recover blood thought to be Darwin's which had spilled on one of his letter possibly through a paper cut... Nothing came out of that attempt.

As for his stress and vomiting syndrome, historians who have written about him suggest that the internal conflicts he was having about the implications of his theory and personal tragedies like the death of this son may have much to do with it.

The medical diagnosticians however say that the stresses and vomiting would probably have disappeared if his other parasitic infections were taken care of. ..  There is enough room for doubt about this.. Darwin had a worrying nature. He agonized over everything.. details of his work, the opinion of his very religious minded wife and the health of his children.. He may have been living in the idyllic English countryside but he had much to worry about. Just curing him of parasites may not have been enough to get rid of the stress.

One final thought... why has this case not been featured on House?  It would have made a great episode..solved perhaps when Gregory House himself was receiving treatment for psychiatric disorder.. or better still with House bursting into the Historical Clinicopathological Conference with a smirk and the answer..

What drama!

Tip: Short Sharp Science

Monday, May 9, 2011

A Long View Of The Age Of Oil

I took this from Ursula Goodenough's post on NPR's Cosmos and Culture blog.

Source: Steve Mayfield

Friday, May 6, 2011

New Indian Wetland Protection Rules May Be Unwieldy And Unworkable

India has a voluble and energetic Minister for Environment and Forest in Mr. Jairam Ramesh who speaks the language of people participation and transparency in matters of protecting India's environment. 

Yet we keep coming up with badly thought out rules. Ashish Kothari of Kalpavriksha an environmental research and action group exposes the shortcomings of the Wetlands (Conservation and Management) Rules notified in 2010.

Missing: The citizen:

.....The above is not an argument against the need for a degree of regulation by state and central governments. Nor against the idea of a central authority. But arbitrariness and abuse of power by such agencies can only be checked by deep democracy, that is, a fully empowered role for local citizens. The Rules are totally silent on this -- it’s as if there is no history of human use and management of wetlands, no local knowledge and practice that may be relevant to their conservation, and no role for elected or self-initiated people’s institutions. The Rules are a mockery of everything the government professes regarding panchayati raj and decentralisation. Fishing, farming, pastoral communities and other villagers and city-dwellers living adjacent to wetlands have no role at all in the identification, management, and regulation of wetlands. 

See here..