[The Well] Drilling problems in Ghana
oyin...@yahoo.com
Our crew in Ghana has run into a problem and we need some advice:
Drilling with cable tool in the Sunyani area (Brong-Ahafo region), the well suddenly collapsed at a depth of 120 feet. The geology is a deeply weathered phyllite with quartzite stringers. Obviously, the best water production comes from the quartzite, but there is a suprising (if limited) flow from the clayey weathered phyllite. After the first collapse, clay and weathered phyllite heaved up into the steel pipe from 120 to 100 feet. Trying to provide advice from the US, I recommended that the crew fill the pipe with drilling mud to keep weight on the formation while they cleaned out the pipe and drilled again. The well collapsed several more times, the last time filling the steel pipe from 140 to 100 feet with clay and mud. Each time, it blew water and mud out the top of the pipe.
I have seen references in the literature to "kaolinic collapse" and "kaolinic porridge" (Ground Water
I'm sure they will be able to free the casing and pull out the steel pipe, but could anyone tell me how to control this collapse in the future? How high will we have to go with drilling mud to keep the hole open while we work? Is there any measurement we can make to design remedy?
Thanks for all your messages: this has been a great help.
Bill Cocke
State of Delaware Water Allocation Program
part-time advisor to Afri-Hope Missions
NGWA is not responsible for the authenticity or accuracy of information contained within this message. Published statements do not necessarily reflect the opinion of NGWA. Products and services that are mentioned or advertised within this site do not carry any kind of endorsement by NGWA.
David Haupt
yield is necessary?
David
oyin...@yahoo.com wrote:
> Hello Well Listers,
>
> Our crew in Ghana has run into a problem and we need some advice:
>
> Drilling with cable tool in the Sunyani area (Brong-Ahafo region), the
> well suddenly collapsed at a depth of 120 feet. The geology is a
> deeply weathered phyllite with quartzite stringers. Obviously, the
> best water production comes from the quartzite, but there is a
> suprising (if limited) flow from the clayey weathered phyllite. After
> the first collapse, clay and weathered phyllite heaved up into the
> steel pipe from 120 to 100 feet. Trying to provide advice from the
> US, I recommended that the crew fill the pipe with drilling mud to
> keep weight on the formation while they cleaned out the pipe and
> drilled again. The well collapsed several more times, the last time
> filling the steel pipe from 140 to 100 feet with clay and mud. Each
> time, it blew water and mud out the top of the pipe.
>
> I have seen references in the literature to "kaolinic collapse" and
> "kaolinic porridge" (Ground Water
> <http://www3.interscience.wiley.com/journal/118538742/home>
> *Volume 11 Issue 5
> <http://www3.interscience.wiley.com/journal/119672243/issue>, *pages
> 31-34, Robert Bannerman). The recommended precautions were
> maintaining adequate head in the borehole while drilling. We were
> surprised that this effect could push water above land surface,
> especially since hand-dug wells in the area were dry at the time. The
> crew was finally able to keep the hole open to 140 feet, and they set
> the screen and casing. However, when the installed the gravel pack,
> the formation heaved up again, pushing the gravel pack up into the
> steel pipe, and locking the pipe to the well screen and casing.
>
> I'm sure they will be able to free the casing and pull out the steel
> pipe, but could anyone tell me how to control this collapse in the
> future? How high will we have to go with drilling mud to keep the
> hole open while we work? Is there any measurement we can make to
> design remedy?
>
> Thanks for all your messages: this has been a great help.
>
> Bill Cocke
> State of Delaware Water Allocation Program
> part-time advisor to Afri-Hope Missions
>
> **
>
> NGWA is not responsible for the authenticity or accuracy of
> information contained within this message. Published statements do not
> necessarily reflect the opinion of NGWA. Products and services that
> are mentioned or advertised within this site do not carry any kind of
> endorsement by NGWA.
>
>
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oyin...@yahoo.com
From: David Haupt <dlh...@plbb.us>
To: the...@ngwa.biglist.com
Sent: Sat, November 7, 2009 7:30:40 PM
Subject: Re: [The Well] Drilling problems in Ghana
How much casing is installed? What is the static water level? What yield is necessary? David
oyin...@yahoo.com wrote:
> Hello Well Listers,
>
> Our crew in Ghana has run into a problem and we need some advice:
>
> Drilling with cable tool in the Sunyani area (Brong-Ahafo region), the well suddenly collapsed at a depth of 120 feet. The geology is a deeply weathered phyllite with quartzite stringers. Obviously, the best water production comes from the quartzite, but there is a suprising (if limited) flow from the clayey weathered phyllite. After the first collapse, clay and weathered phyllite heaved up into the steel pipe from 120 to 100 feet. Trying to provide advice from the US, I recommended that the crew fill the pipe with drilling mud to keep weight on the formation while they cleaned out the pipe and drilled again. The well collapsed several more times, the last time filling the steel pipe from 140 to 100 feet with clay and mud. Each time, it blew water and mud out the top of the pipe.
>
> I have seen references in the literature to "kaolinic collapse" and "kaolinic porridge" (Ground Water <http://www3.interscience.wiley.com/journal/118538742/home>
> *Volume 11 Issue 5 <http://www3.interscience.wiley.com/journal/119672243/issue>, *pages 31-34, Robert Bannerman). The recommended precautions were maintaining adequate head in the borehole while drilling. We were surprised that this effect could push water above land surface, especially since hand-dug wells in the area were dry at the time. The crew was finally able to keep the hole open to 140 feet, and they set the screen and casing. However, when the installed the gravel pack, the formation heaved up again, pushing the gravel pack up into the steel pipe, and locking the pipe to the well screen and casing.
>
> I'm sure they will be able to free the casing and pull out the steel pipe, but could anyone tell me how to control this collapse in the future? How high will we have to go with drilling mud to keep the hole open while we work? Is there any measurement we can make to design remedy?
>
> Thanks for all your messages: this has been a great help.
>
> Bill Cocke
> State of Delaware Water Allocation Program
> part-time advisor to Afri-Hope Missions
>
> **
>
> NGWA is not responsible for the authenticity or accuracy of information contained within this message. Published statements do not necessarily reflect the opinion of NGWA. Products and services that are mentioned or advertised within this site do not carry any kind of endorsement by NGWA.
>
>
> You are subscribed as dlh...@plbb.us
NGWA is not responsible for the authenticity or accuracy of information contained within this message. Published statements do not necessarily reflect the opinion of NGWA. Products and services that are mentioned or advertised within this site do not carry any kind of endorsement by NGWA.
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David Haupt
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David L. Haupt
Auburndale, WI
715 652 2711
dlh...@plbb.us
oyin...@yahoo.com
You're right about the development. Every one of the wells in this area is painfully slow and difficult to develop because they make so little water. While I was there "advising" (i.e. experimenting and hoping for the best), we tried recirculating water during air lift development. This helped speed up the initial phase of development, but did not reduce the long days of development needed in the worst cases. Some of those wells just seemed to tap into a reservoir of mobile, runny clay.
The heaving muddy clay seems to indicate some kind of artesian conditions, which makes sense when drilling in the valleys near the gneiss and granite ridges. Many of the wells with hand pumps have a steady flow of water coming out from under the base of the pumps after the seals age for a few years. There may be an area of recharge at higher elevation, where water is getting into these zones that we're finding below 100 feet. After drilling through 120 feet of clay, it's not hard to imagine that there is some confinement. I don't think I'm seeing the entire composition of the material, because only the clay is making it to the surface. But without any geologic maps, I'm just speculating.
I don't know if this clarifies the situation or just makes things worse. Your comments are greatly appreciated.
Bill
Subject: Re: [The Well] Drilling problems in Ghana
The well was set with casing from land surface to 126 feet, with screen from 126 to 138. There was still 130 feet of steel pipe in the hole when it collapsed. Most of the wells in the area produce from 1 to 5 gallons per minute, and that range is acceptable for this well. We won't know the static water level until the situation is stabilized and the hole is cleaned out.
From: David Haupt <dlh...@plbb.us>
To: the...@ngwa.biglist.com
Sent: Sat, November 7, 2009 7:30:40 PM
Subject: Re: [The Well] Drilling problems in Ghana
How much casing is installed? What is the static water level? What yield is necessary? David
oyin...@yahoo.com wrote:
> Hello Well Listers,
>
> Our crew in Ghana has run into a problem and we need some advice:
>
> Drilling with cable tool in the Sunyani area (Brong-Ahafo region), the well suddenly collapsed at a depth of 120 feet. The geology is a deeply weathered phyllite with quartzite stringers. Obviously, the best water production comes from the quartzite, but there is a suprising (if limited) flow from the clayey weathered phyllite. After the first collapse, clay and weathered phyllite heaved up into the steel pipe from 120 to 100 feet. Trying to provide advice from the US, I recommended that the crew fill the pipe with drilling mud to keep weight on the formation while they cleaned out the pipe and drilled again. The well collapsed several more times, the last time filling the steel pipe from 140 to 100 feet with clay and mud. Each time, it blew water and mud out the top of the pipe.
>
> I have seen references in the literature to "kaolinic collapse" and "kaolinic porridge" (Ground Water <http://www3.interscience.wiley.com/journal/118538742/home>
> *Volume 11 Issue 5 <http://www3.interscience.wiley..com/journal/119672243/issue>, *pages 31-34, Robert Bannerman). The recommended precautions were maintaining adequate head in the borehole while drilling. We were surprised that this effect could push water above land surface, especially since hand-dug wells in the area were dry at the time. The crew was finally able to keep the hole open to 140 feet, and they set the screen and casing. However, when the installed the gravel pack, the formation heaved up again, pushing the gravel pack up into the steel pipe, and locking the pipe to the well screen and casing.
NGWA is not responsible for the authenticity or accuracy of information contained within this message. Published statements do not necessarily reflect the opinion of NGWA. Products and services that are mentioned or advertised within this site do not carry any kind of endorsement by NGWA.
Brennan, Michael
In Michigan, one procedure that I have seen when using cable-tool to install a production test well under artesian conditions for the purpose of performing an aquifer test is as follows (noting the well was screened from 80-90 feet below ground surface within a buried glacial outwash channel beneath a clay confining unit):
· Casing advanced 10’ past desired interval, while adding bentonite around the outside of the casing to ensure you won’t develop leakage around the outside of the casing
· Smaller diameter screen fitted with rubber packer pushed through the casing to desired interval (perhaps you could use a pre-packed screen if needed)
· Surface casing bumped back and removed to expose screen, while screen held in place by drill bit attached to smaller drill string assembly
· After development, pump lowered and fitted with flow control valve to allow for aquifer test
The other experience I will add is if you are aware or can estimate the height above the ground that your artesian well will rise, you should be able to stack casing above ground to control the pressure. I have observed success in stacking casing (some times as much as 25 feet above ground surface) to let the artesian pressure come to equilibrium, thus allowing the well to be completed or abandoned. A hydraulic lift was used in these situations and can present some challenges, but thought I would pass this along.
Good luck.
Mike
*If interested the State of Michigan has a flowing well handbook which I have found very useful and can be found here.
Malcolm Pirnie of Michigan, Inc.
(Offices Nationwide)
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