This is a simple practical Field Guide for performing Straddle Packer tests (pressure testing) in the field. The document is prepared by Ankan Basu and should be used only as a guidance. Every project is different. Modify your needs as required in the field. Contact author for further assistance at admin@coalgeology.com
- Prepare Packer Set up.
- Go to desired Packer test interval.
- Run 3 well volume of water before inflating the packers.
- Inflate Packers – apply pressure based of depth and height of water column above the packer.
- Apply pressure – usually applied P=0.5xdepth of packer.
- Spend 5-20 minutes to stabilize the system.
- Take flow measurements at desired interval.
- Once flow is stabilized, deflate packers and move to the next zone.
Schematic Diagram of Packer Tests
| Goal of Packer Tests: Determine Permeability of Rock Strata |
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Before Packer Test:
Understand the Project and goal:
- Why a Packer Test is required?
- What kind of accuracy level is expected from the study? (Larger Packer Interval vs Shorter Packer interval)
Gather Site Specific information
- Get general geologic map of the area if available.
- Check for existing borehole log or geophysical log in the vicinity of the site.
- Get location map, road direction, total depth of drill hole, drill hole id and related information.
Get ready before you leave office
- Open reel Tape Measures-300 Feet; multiple depending on the depth of the drillhole.
- Calculator
- Stop Watch
- Measuring Tape
- Camera
- Ruler
- Marker
- Water Meter
- Pencils
- Erasers
- Pocket Knife
- Field notebook
- Field log sheets
Driller’s will bring:
- Packers
- Nitrogen Tank-should carry at least two
- Different types of pressure gauges (such as 0-200; 0-300; 0-400; 0-600 psi)
- Flow meters -Must carry multiple ones
- AQ rods or 1 inch water line.
While Drilling the borehole
- Geologic log
- Fracture log
- take photographs
- Look for fractures, slikensides, broken zones, coal seams and coal spars and other potential zone of high water flow.
- Schedule geophysical logging
Geophysical Logging of borehole for Packer Test
- Open hole geophysical logging is recommended if borehole condition is stable that allows the caliper tool to detect any fracture.
- Run temperature log to see any possible movement of water indicated by change in water temperature (and resistivity too).
- Acoustic Televiewer: Acouistic Televiewer (ATV Log) 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
- Check water table elevation
- Determine test zone intervals based on all available information including photographs, acoustic televiewer log, E-log, caliper log, temperature log etc.
- 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.
- Write down all zones to be tested in order on a page for quick reference.
- Have some idea about the flow-rate in different zones to be tested based on available information. Such as a highly fractured zone is expected to show high flow-rate.
- Examine setup of the flow-meter, water gauge, bypass valve, take photograph of the setting.
- Examine packers, set up packer assembly, measure packer length, interval length etc.
- Measure distance of the flow gauge above ground.
- Set up a reference point point for depth calculation.
General Packer Set Up
| Steps of running Running Packer Tests |
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Practical Tips and Troubleshooting Packer Tests •
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 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.
- 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
Required Back Pressure
- 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).
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
- Air line blew off (more common)
- Packers busted (Packers can rupture if set at a fracture zone)
- Packers may not be sealing properly, increase packer inflation pressure, rerun the test.
- If still getting high flow in higher inflation pressure – Flow meter may be responding to pressure when there is NO FLOW. Test flow meter.
- 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.
- 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.
Article by Ankan Basu; P.G; Coal Geologist. Contact Ankan Basu for your project needs at admin@coalgeology.com
Here is the POWERPOINT PRESENTATION prepared by Ankan Basu for Packer tests in the field.
thank you for this detail description.It help us to collate the propriety of our site works.
regards
p. delov
You are most welcome. Let me know if you need further assistance.
WE are geotechnical company in Sri Lanka. We need some catalagues,prices and specification for Pnuematic packers using for water pressure testing.
Thanks
Geo Engineering Consultants (Pvt) Ltd
Dear Sir
We have been producing inflatable packers since 1990 in Ankara TURKEY.
?f you are interesting to sell or use our product please contact us.
our web site: http://www.dcemakina.com and http://www.star-packer.com
our tel:0090 312 394 8200
fax:0090 312 394 82 02
mobile:0090 535 780 60 28
best regarts.
Deha SOMUNCUOGLU
Dear Sir
We have been producing inflatable packers since 1990 in Ankara TURKEY.
?f you are interesting to sell or use our product please contact us.
our web site: http://www.dcemakina.com and http://www.star-packer.com
our tel:0090 312 394 8200
fax:0090 312 394 82 02
mobile:0090 535 780 60 28
best regarts.
Deha SOMUNCUOGLU
Try Bimbar Packers Mr. Hikkaduwa. I have used them before. Pretty good and should not be too expensive.
Description of company:
Geopro is an independent company which specializes in the design, manufacture, and assembly of inflatable packers made of BIMBAR dilatable hose.
The Geopro staff is mainly made of engineers, geologists and technicians as its main concern involves consistent technical improvement and regular product innovation. Faithful to these values and its commitment to quality, Geopro has positioned itself among the leading companies in the industry of inflatable packers.
Since its creation, Geopro has been building a strong network of customers. Today, Geopro exports its BIMBAR inflatable packers in more than 80 countries.
This achievement is without any doubt the result of very high quality standards, and illustrates how reliable our products are in the ever-challenging market of extraordinary ground works, as well as the construction of hydro-electrical dams. Our technical department is a testimony to excellence and reliability.
In the last few years, Geopro has been developing innovative packers and an array of systems designed for the manufacturing and rehabilitation of water wells in close cooperation with IPI Pty Ltd Australia.
Webpage: http://www.geopro.be/index.php/inflatable-packers/inflatable_packers.html
For water wells, we typically use: Drill Stem Test (DST) Packers.
Water Well DST
Water Well DST is a method of selectively producing isolated portions of a well in order to determine the water quality from each level separately before the well is completed.
Such information can be used to determine which of a range of aquifers may be used for production and which should be isolated from production.
IPI supply a broad range of open and cased hole, straddle packer assemblies and associated equipment for use in such DST work.
Here is link to another manufacturer you may consider: http://www.inflatable-packers.com/WaterWell.htm
I have added my SECRET (!!!) presentation that I use and update each time I go for a Packer Test job. If you need my help, you know how to contact me.
I have guys on site and getting new operators up to spead is always a problem.
Roy
Hi Ankan,
I had a couple of problems while doing and deciding about Packer test, like Can we perform packer test in sand?
Or it would be considered as doing an experiment, if we do it in sand layer?
Do we have to wait for five minutes after setting up each pressure or can take reading straight away?
What is the best interval of time,once we start taking reading?, every minute or every five minutes?
Do we have to wait for 3 consecutive reading or just take whatever the reading at every decided interval?
Hope for good response,
thanks.
Yogesh, you can not do Packer test in sand. In fact, you can’t do it in any soft material or fractures, not even in coal. It must be hard rock to perform packer tests. I am talking about straddle packer. However, there may be a way do a single pacer test if you have hard rock below the sand portion. I would not recommend it, you would be better off doing a lab test.
You don’t have to wait for 5 mins if you believe your pressure is stabilized. I prefer waiting some time so that I can monitor the pressure. Remember that our goal is to keep the pressure CONSTANT for the entire period of the test.
Best interval of time depends on the strata. If it is taking a lot of water – take reading at 1-2 min intervals. Like, if you encounter a fracture, you may be pumping at the maximum pump capacity and still could not generate enough head. No point running the test for hours. However, when you have tight material like a shale unit, you need longer tests. Interval does not matter as long as you see the change. In a practical world, I often run a total of 1 hr test on shale horizon, with readings in every 5 minutes.
Take reading at every interval. Decide the interval based on your strata behavior.
Hope this help.