Packer Test Guide: Straddle Packer Tests; Hydraulic Conductivity Tests, Geological Consulting-Ankan...

Prepared by Ankan Basu, Geologist, MMA 1

STRADDLE PACKER TESTSPractical Field Guide

and Troubleshooting

Prepared by

Ankan Basu, P.GGeologist

Marshall Miller and AssociatesEmail: [email protected]: [email protected]

mailto:[email protected]


DISCLAIMER


Most of the materials covered in this presentation is from my OWN collection.I have completed various projects involving Packer tests up to 1000 feet deepboreholes. I have used some of the information from Packer Manuals fromdifferent manufacturers.

Please contact me at [email protected] if you need help with a hydrologicinvestigation project.

In coal fields, most commonly Packer Tests are conducted before shaft/slope construction and crossing a creek for mining needs.

If you have any questions, please let me know.Ankan Basu, P.GGeologist / HydrogeologistMarshall Miller and AssociatesBluefield, VA, 24605.304-809-0544



Calculate Inflation Packer Pressure: This is an online tool written by Ankan Basu that would calculate required inflation pressure.http://coalgeology.com/utility/packerpressure.html

http://coalgeology.com/utility/packerpressure.html




Unconfined Pressure Curve


Common Problems!The air line can only stand up to 333 PSI pressure! When you are 500 feetDown how much inflation pressureDo you usually use?


Twisted TAM Packers!

Prepared by Ankan Basu, P.G, Geologist/Hydrogeologist , MMA 8

TAM packers – busted as geologists use 700 PSI Inflation Pressure. Drillers gave misleading information about the packer type.


This is an example of Badger Flowmeter rated for 150 PSI. With this type ofFlowmeter you can only packer test shallow holes upto 300-400 feet.


This is a PSI digital flow-meter rated for1000 PSI injection pressure.


Straddle Packer Tests (Pressure Testing)

T=K*b [b=Packer Test Interval]

Goal• Isolate specific section of the bedrock in a

borehole (usually 10 feet)• Perform Packer test and collect samples (if

required) from a particular zone.• A series of such tests will provide

information about vertical distribution of water quality and hydraulic conductivity

• Determine PERMEABILITY OF BEDS

T=Transmissivity; K=Conductivity


Basic Method• Measure water table.• Determine pneumatic pressure required to inflate

the packers.• Lower Packer Assembly to desired test zone inflate

packers.• Monitor Pressure at flow gauge to ensure

equilibrium/stable flow conditions.• Remove 3 well volumes of water before running each

test; also removes air bubbles.• Monitor and record flow from the flow meter at

desired interval of time (usually 5 minutes).


General Configuration

Inflation Tube (A

ir line)

Drill P

ipe

Inflatable Packer

Inflatable Packer

Straddle Test Zone

Perforated Pipe

End P

lug

Top Packer Bottom Packer


Useful Tip for Packer Set Up

Sliding EndSliding End

Have the sliding ends as shown in the diagrams

In this set up, we don’t need any slack in the air line between the packersas the thickness of test zone z1 remains constant. We only need about 1 feet slack at the top of the packer assembly.

During inflationTop Packer- retracts DOWNBottom Packer-retracts UP

Prepared by Ankan Basu, Geologist, MMA 15Source: Bimbar Packer Manual


Graph for working Pressure

Source: Bimbar Packer Manual


BIMBAR Accesories



Other Accessories



Set up of the Water Measurement Line

Flow Gauge

Flow meter BY

PA

SS

L

INE



Hand pump to inflate Packers



Other Airline Accessories



Safety TipsPacker Inflation: Water is favored over N2 gas (or neutral gas). Other fluids are prohibited such as O2.

While inflating with gas for longer period of time, GAS POCKETS may appearat the outer cover of the packers (run water for 3 well volumes to remove any air bubbles before each tests.

Inflation Pressure: Must be always greater than the injection pressure for proper seal.

Deflation of Packer: Do not move packers before complete deflation.


Phases of Packer Tests

1. Drilling2. Geophysical Logging3. Packer Testing


Phase 1: Drilling

• Geologic and geotech log• Fracture Log• Photograph core• Look for fractures, slickensides, broken zone,

coal seams, iron staining, soft rock such as clay and clay-stone etc.

• Note: Record depth of such zones: Possible high flow areas.


Geophysical Logging

• OPEN hole logging recommended if borehole condition is stable.

• Density log• Gamma Log• Temperature Log • Resistivity log (watch for change in resistivity-indicates flow)• Caliper log (Very useful identifying fractures in the hole)• Acoustic Televiewer log (Most important in visual and

accurate identification of fractures and their orientation)


Use available information to indentify possible high flow zones

Possible Fracture/Coal Seam

Coal Seam, Broken while logging

Sandstone-Shale Contacts


Indentify and Straddle zones of possible high flow first

Caliper Log ShowingFRACTURES


Acoustic Televiewer Log showing Fractures

1 and 2 : Expect moderate flow if not connected to other fracture zones.3: Expect high flow (Field Data showed 23 GPM at max pump capacity)

1 2 3

Note: Zone 2 also showed 23 GPM flow. So, the fracture is probably connected to thefractures at zone 3.


Acoustic Televiewer Log showing the coal seam, thin bedding plane fractures and highly broken zone

Coal seamHighly fractured zoneFew bedding plane

fractures

Flow=0.04 GPM Flow=23 GPM Flow=23 GPM

1 32

Note: Multiple scattered fractures at zone 2 showed equal amount flow as highly fractured section zone 3.


Identify zone of no intake – great to check if Packers are inflating and sealing properly.

Coal seamHighly fractured zone

Expect low or NO flowGood zone to test if

Packer is sealing properly


Before Packer testing

• Check water table elevation – needed parameter for calculation of inflation pressure for the packer.

• Record inner and outer diameter of AQ rods/ 1 “ pine – Needed parameter to calculate friction loss.

• Decide Packer interval and set up Packer Assembly.• Measure all units within the packer assembly (see picture).• Measure stick up of the pipelines above ground.


Before Packer Testing Continued.• Measure distance of flow gauge above ground-required for K calculation.• Set up reference point to measure depth at the drill.• Determine all test zone intervals and note down in field book for quick

reference.• Make sure that the Bottom and Top packers are not sitting at a fractured zone or

coal seam.• Take photograph of the Packer Assembly.• Determine pneumatic pressure required to inflate the packers including the

height of the water column in the borehole.• Check FLOWMETER – RECORD Flow Meter TYPE and SERIAL NUMBER• Check for any leaks, RECORD PACKER TYPE and SERIAL Number.

3 feet above ground


Draw Schematic Diagram

PUMPDischarge Line

BY

PA

SS

LINE

Shut off Valve(Not required)

BYPASS ValveRequired

Flow Meter Pressure Gauge

AQ Rods

ELBOW

1 inch adapter is used to connect the HIGH PRESSURE lineto the AQ rods. Valves at the ELBOW are used to controlBack Pressure if required.

High Pressure Line


CHECK FLOWMETER• Always start with checking the accuracy of the flow meter.• 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.


Caution using Flow meter• 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.

• 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.


Set Up of the Water Line


Test Packer Assembly for Leaks

• Check for possible leaks in the airline• Check for possible leaks in the pipes, joints and

connectors• Inflate packers at surface up to 90 PSI (max) to check

that the packers are inflating properly.• 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.

• If the pressure is stable, go to next step – PACKER TEST at the CASING.


TEST 1 for any PACKER TEST project should be in the casing

• Inflate packer up to 250 PSI.• Run water between 10 to 150 PSI.• 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.

• After the test in the casing, go down to the bottommost zone to be tested and start testing.


Record the TYPE and SERIAL NO. of the FLOW METER


Tips for Packer Tests-Injection 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.


Sensus Flow meter broken due to too high pressure


Inflation PressureNever use below 350 PSI inflation pressure even when close to the surface.

Source: http://www.qsppackers.com/


More Practical Tips

• Before starting each test run at least 3 well volumes of water to remove any air bubble before inflating the packers.

• 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.

• Look for leaks at the adapter near ELBOW and valves for leaking water.

• Keep enough slack in the airline at the top of the packer assembly (at least 1 feet).


Tip: Tap the Flow meter• Most of the flow meters record flow well at higher flow. But at

low flow some of the flow meter would record flow with a little tapping at the side. Without tapping, it would indicate NO FLOW. This is a mechanical problem. If you see very low flow rate, tap the flow meter between and before each readings.


Tip 1: Use 0-200 flow gauge if working in a 400 feet deep hole

0-200 PSI Range

0-600 PSI Range

Tip 3: Record flow only when the pressure stabilizes

Tip 2: Increase inflation pressure by closing the BYPASS valve very SLOWLY. Pressure may build up quickly and break flow meter.


Troubleshooting

Water gushing out of the hole-1. Air line blew off2. Packers busted

• Commonly the airline blow off due to lack of slack.

• Packers can rupture if set at a fracture zone.


Troubleshooting-High Flow in Tight looking zones• 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.


Troubleshooting: Zero Flow

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

• Some flow-meter can not record very low flow (0.01-0.04 gpm or less).

• Check manual for the particular flow-meter for lower sensitivity range.

• Perform Accuracy test 2 for the flow meter.


More Tips• No Back Pressure at Maximum Pump Capacity –

reduce the length of the pressure test till you get any back pressure. However, the test section should NOT be shortened below A/D< 5.

• A= Length of test section• D=Diameter of Hole

• Never use >20 feet of Test Section.• For Most Pumps – Maximum capacity ~ 25 GPM


Tip: Use TAPE Reel instead of counting rods

• Use tape measure to keep track of depth.

• Set the bottom of the top packer as “0” feet.

• Tape the tape measure along with the airline while going down the hole.


Use Tape instead of counting rods


Useful to have at least two N2 tanks


A view of a Packer Test Site

Thread Sealer

AQ Rods

AirlineTape


Check for Leaks at Surface

1. Inflate Packers up to 90 PSI (max)2. Listen for any hissing sound.3. Watch the Pressure gauge at the N2 tank. If pressure drops, we have a leak.4. Tight Joints in the airline.


Use enough Pneumatic Pressure but not too much

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.


Leak in the airline


Record the type of Packers

BIMBAR PACKERS


Common Leak at the end seal of Bottom Packer


Packer Set Up

Bottom Packer

Bottom end of Bottom Packer Slides UP


Extreme Test of Packer Set Up

Extra Surface Casing

Packer Assembly inflated completely at surface within surface casing. Turning the flow should show proper seal and no leakage of water at either end of the casing.


Example Test:Coal Seam at ~ 90 Feet

Inflation Pressure: 400-425Water Pressure: 45 PSI (max)

Could NOT raise the pressure at the flow gauge above 15 PSI even when pumpingWater at the maximum capacity of the pump.Result: 23 GPM

Note: Not all coal seams take a lot of water. This particular coal seam is broken at thebottom half along with some coreless possibly due to fracture.

Coal at 90 feet - 23 GPMAbout 5.2 Feet/Day

Sandstone immediately below the Coal Seam ~7.0 GPM; About 0.9 Feet/Day


Zone Broken, with fractures: EXPECT HIGH FLOW

Depth of Zone: 125-135Pneumatic Pressure needed- 400-425 psi

Test Conducted at 20 PSI water pressure at max pump capacity.Test result: about 22 GPM, 6.2 Feet per day

Note: The water intake is very close to the pumping capacity of the PUMP itself.


380-390 feet0 gpm 370-380 feet 0 gpm

360-370 feet 0.57 gpm 350-360 feet 0.04 gpm

340-350 feet—0.04 gpm 330-340 feet0.04 gpm

Expected range of flow in different types of rock


Not all coal seams display high flow

Not all coal seams take a lot of flow. The seam here is hard, not fractured and only took 0.57 gpm

The coal seam here is brokenat the bottom and has a middleSoft shale unit.

Took 23 gpm at maximum pumpcapacity.


Thread Sealer Use Thread Sealer

Record Packer typeand Serial Number.

More Field TIPS


Read the pressure gage at the N2 Tank BEFORE, AFTER and DURING test.

Drop in pressure indicates leak inthe airline. Packers may notseal if the pressure drops belowthe required inflation pressure.


Packer Test in two nearby boreholes to indentify path ofWater flow/fracture.

Image Reference: il.water.usgs.gov/pubs/ofr01-50_chapter4_8.pdf

Example Application


Recording Data

• Always run for at least 5 minutes before starting to take any readings.

• Make sure the injection pressure is stable over the period of test.

• At low flow allow more time to equilibrate the system and to get any measurable flow.


Formula to calculate Permeability


Required INPUT Parameters• A=Length of test interval (usually 10 feet)• r=Radius of borehole (usually 0.125 feet)• Cs=Conductivity coefficient =80 when A=10, r=0.125

(from published graph, Page 263 Ground water Manual, Fig-10.8)

• h1=distance from gage to water table• h2=applied pressure at Gage• L=Friction loss of pipe• Q=Steady Flow Rate


Calculations

• Need “Inside Diameter” of Type of rod used for packer testing for calculation of head loss per 100 feet from chart (Hydraulics Field manual page 6.32)

• Contact Ankan Basu, P.G for details of calculations at [email protected]


Packer Test Guide: Straddle Packer Tests; Hydraulic Conductivity Tests, Geological Consulting-Ankan...

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