volcanism

Key Phrases on the Book:
glass mountain, Geólogos de México, Université du Québec, altered lithic clasts, outward dipping reverse faults, subaqueous calderas, roof aspect ratio, hunter mine caldera, lithic clast types, crustal segment hosting, graben caldera, normal ring fault, pyroclastic dikes, volcanic lithofacies, clast analyses, stepwise aggradation, caldera growth, caldera unrest, chamber analogue, other radioactive clocks, lower formational stage, failure forecast method, caldera geometry, upper formational stage, natural calderas

Buy Caldera Volcanism, Volume 10: Analysis, Modelling and Response (Developments in Volcanology)

Global Tectonics will find its place in all well equipped libraries and a personal copy will be of use for any geoscientist who needs a comprehensive overview. (Surveys in Geophysics, September 2009)

tectonics

This textbook provides a comprehensive overview of the field of global tectonics. Because the field has changed significantly since the last edition was published, the majority of text and figures in the third edition are new. ( Book News, September 2009)

• Paperback: 496 pages
• Publisher: Wiley-Blackwell; 3 edition (January 20, 2009)
• Language: English

Peat-Lignite-Sub Bitunimous- Bitunimous- Semi Anthracite – Anthracite – Meta anthracite.

The “rank” of coal refers to the degree of coalification.

The coalification process has two main distinct phases

1. Initial Biochemical Phase – Processes that operates during the diagenesis of swamp deposits. The process stops with the formation of “Hard Brown Coal”. Biochemical phase of coalification is primarily controlled by bacteria. Other factors such as pH and depth to the groundwater can also affect the coalification process during this stage. Reduction of moisture content is the most obvious end result of the biochemical phase.
2. Geochemical Phase / Metamorphic phase: Geochemical phase could be intense with rapid change in carbon content of the initial peat deposit due to change in pressure and/or temperature. With increase in rank of the coal, the % of carbon increases with the reduction of % hydrogen and % Oxygen. Methane and CO2 are the main by-products of this phase.

1. Change in Temperature: This can be either direct contact with minor intrusion producing high heat or just increase in temperature with burial.
2. Time – if the rate of burial is too high, sediments will  not have enough “cooking time” to produce high rank coal from peat.
3. Pressure: Most pronounced requirement for the compaction phase.
4. Radioactivity: It is rarely observed to achieve higher rank due to readioactive material within the rock.

Now you know.

MODUELO 2: A new version of an integrated simulation model for municipal solid waste landfills [An article from: Environmental Modelling and Software]

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Methane Gas in Landfills –
Anaerobic microbes decompose the waste products and thereby produce “Landfill Gas”. The landfill gas is composed of 50% methane and 45% of carbon-di-oxide. Landfill contributes about 7% of the total methane emission worldwide. Methane is also the most abundant organic chemical in atmosphere.Regulation of the emission of methane from the Landfills helps reduction of odor due to methane gas and also reduces the global warming potential.

The rate of gas production from a landfill is controlled by various factors such as –

• Composition of garbage
• Moisture content
• Partial pressure of methane gas

landGEM by EPA

Organic Components –>Amino Acids –> Intermediate and Simple fatty acids –> mostly acetic acid

• Beneficial and profitable is enough methane gas can be generated and used as a source of energy.
• Helps reduction of methane emission to the atmosphere, thereby reduce global warming.
• EPA regulations under the Clean Air Act require landfill owners to collect or combust landfill gas.
• LFGTE (Landfill Gas To Energy) projects offer alternate source of energy, create associated jobs.
• The Landfill Methane Outreach Program (LMOP) was created as a part of President Clinton’s Climate Change Action Plan which has more than 200 Allies and Partners who have voluntarily working with EPA to develop cost effective LFGTE projects.
  

What could be the reason? Guess and reply.

Packers Bent due to some reason

Perforated Rods Bent

Schamatic Diagram of Packer Tests

Before Packer Test:

Understand the Project and goal:

1. Why a Packer Test is required?
2. What kind of accuracy level is expected from the study? (Larger Packer Interval vs Shorter Packer interval)

Gather Site Specific information

1. Get general Geologic Map of the area if available.
2. Check for existing borehole log or geophysical log in the vicinity of the site.
3. Get location map, road direction, total depth of drill hole, drill hole id and related information about the proposed drilling.

Get ready before you leave office

1. Open reel Tape Measures-300 Feet; multiple depending on the depth of the drillhole.
2. Calculator
3. Stop Watch
4. Measuring Tape
5. Camera
6. Ruler
7. Marker
8. Water Meter
9. Pencils
10. Erasers
11. Pocket Knife
12. Field notebook
13. Field log sheets

1. Packers
2. Nitrogen Tank-should carry at least two
3. Different types of pressure gauges (such as 0-200; 0-300; 0-400; 0-600 psi)
4. Flow meters -Must carry multiple ones
5. AQ rods or 1 inch water line.

While Drilling the borehole

1. Geologic log
2. Fracture log
3. take photographs
4. Look for fractures, slikensides, broken zones, coal seams and coal spars and other potential zone of high water flow.
5. Schedule geophysical logging

Packer Test Site

Geophysical Logging of borehole for Packer Test

1. Open hole geophysical logging is recommended if borehole condition is stable that allows the caliper tool to detect any fracture.
2. Run temperature log to see any possible movement of water indicated by change in water temerature (and resistivity too).
3. Acoustic Televiewer: Acouistic Televiewer is widely used for fracture detection in the subsurface and also useful to determine dip of beds etc. Read more about Acoustic Televiewer.

Before starting Packer tests

1. Check water table elevation
2. Determine test zone intervals based on all available information including photographs, acoustic televiewer log, E-log, caliper log, temperature log etc.
3. While determining the test zone intervals, do not set the top or bottom packers in soft zones, fractures or in the coal seams. The packer may rupture while inflating in contact with a fracture and the packer may not seal properly when in contact with the coal seam.
4. Write down all zones to be tested in order on a page for quick reference.
5. Have some idea about the flowrate in different zones to be tested based on available information. Such as a highly fractured zone is expected to show high flowrate.
6. Examine setup of the flowmeter, water gauge, bypass valve, take photograph of the setting.
7. Examine packers, set up packer assembly, measure packer length, interval length etc.
8. Measure distance of the flow gauge above ground.
9. Set up a reference point point for depth calculation.

General Packer Set Up

Pracktical Tips and Troubleshooting Packer Tests •

FLOMETER CHECK -Always start with checking the accuracy of the FLOWMETER

Calibration check: Use bucket with 1-5 gallons mark to check calibration, fill up the bucket up to 5 gallons and check the reading at the flow meter. Very rarely 5 gallons at the difference in reading at the flow meter would equal to 5 gallons in the bucket. Usually the flow meter reads less flow. Use calculator to get conversion factor.
Example: 4 gallon at flow meter=5 gallons at the bucket
Calibration factor=1.25 X flow meter reading.

Accuracy Check 1: Some flow meter respond to pressure and record flow when there is no actual flow. Close the valve to the HIGH PRESSURE LINE so that no flow is going to the packer assembly, apply pressure at the water gauge between 0-150 PSI. In ideal situation, there should not be any flow. But some flow meter show higher flow with higher pressure when there is NO FLOW at all. Change flow meter.
Accuracy Check 2: Some flow meter works great at higher flow but could not detect low flow. Let the water run under very low pressure and collect the water with a bucket. Test it as low as 0.1 GPM (10 minutes to fill up 1 gallon at the bucket). Trial and Error to get required flow.

Do NOT use too much Pressure: Different types of flow meters are made for different purposes and they all have different limit of maximum pressure that they can perform. If you apply more pressure than the flow meter is built for, it will break. Commonly the bottom part the flow meter breaks due to high water pressure.

Broken Flowmeter

Read the manual of the particular flow meter: Check the range of pressure for which the flow meter works (see manual).  If working in a deep borehole, talk to the drillers before reaching the site about high capacity flow meter. Drillers should carry multiple flow meters.

After each test wide open the BYPASS VALVE.

CHECK for Leaks in the Airline

1. Check for possible leaks in the airline
2. Check for possible leaks in the pipes, joints and connectors
3. Inflate packers at surface up to 90 PSI (max) to check that the packers are inflating properly.
4. Keep it inflated at a set pressure for 5 minutes. If the pressure at the N2 pump drops, you have a leak. Search and fix.
5. If the pressure is stable, go to next step – PACKER TEST at the CASING.

TEST 1 for all Packer Tests Should be in the CASING

1. Inflate packer up to 250 PSI.
2. Run water between 10 to 150 PSI.
3. If flow meter records any flow-then either the packers are not sealing properly or the flow meter is responding to pressure. Change flow meter and rerun test till you get 0 gpm flow in the casing.
4. After the test in the casing, go down to the bottommost zone to be tested and start testing

Required Back Pressure

Required Water pressure (injection pressure)=0.5xdepth of test zone Example, at 100 feet depth, 50 PSI injection pressure is required. Note: If you get measurable flow below 50 PSI, then no need to raise to the maximum required pressure. If you get no flow, test up to the maximum required pressure for a zone.

Some more practical Tips

•

1. Before starting each test run at least 3 well volumes of water to remove any air bubble before inflating the packers.
2. While going down hole, make sure each joints between the AQ rods (or the 1 inch water line) is sealed properly. Use “THREAD SEALER” if required.
3. Look for leaks at the adapter near ELBOW and valves for leaking water.
4. Keep enough slack in the airline at the top of the packer assembly (at least 1 feet).

DO NOT use too much of inflation pressure

• Use enough pneumatic pressure to inflate the packers at certain depths properly.
• But if too much of pressure applied to inflate the packers-
• •Packer may rupture
• •Rock strata may fracture
• •Too high back pressure may cause other accidents too.

Troubleshooting Packer Tests

Troubleshooting is a very important part of Packer Testing. The Theory and set up is very simple but numerous things could go wrong in the field. I am only listing few that I have encountered. Feel free to send me some feedback about other problems with Packer Tests and how to troubleshoot them.

Troubleshooting: Water gushing out of the hole-

1. Air line blew off (more common)
2. Packers busted (Packers can rupture if set at a fracture zone)

In both cases, pull all the rods.Fix the problem and restart.High Flow in a tight shale or sandstone indicates mechanical problem

1. Packers may not be sealing properly, increase packer inflation pressure, rerun the test.
2. If still getting high flow in higher inflation pressure – Flow meter may be responding to pressure when there is NO FLOW. Test flow meter.
3. Other possible cause- possible leak in the joints of the AQ rods. Find a zone of crystalline sandstone. Run the test.

Note: I had 1.5 -2.0  gpm of flow in a 200 feet strata composed of tight shale and sandstone (seen from core, verified by Acoustic Televiewer log). Bad data due to flow meter responding to PRESSURE.

No Flow for a long thickness of the strata may also indicates mechanical problem.

1. Some flow-meter can not record very low flow (0.01-0.04 gpm or less).
2. Check manual for the particular flow-meter for lower sensitivity range.
3. Perform Accuracy test 2 for the flow meter.

•