Know about geophysical investigation for borehole drilling, Foundation/Engineering investigations, Environmental/Pollution studies and Mineral Exploration.

I put this up so we can have a slight understanding about Wat geophysical investigations really entails. I will try to limit the use of technical terms.

Connect with me using 09070441895

I won't bother going into oil and gas. Will prefer to stick with what we interact with as a common man and these are borehole drilling, Foundation/Engineering/Dam site investigations, Environmental/Pollution studies and let's say Mineral Exploration.

Starting with borehole drilling for water.

Borehole Drilling differ from place to place. What you will encounter in Ibadan is different from what is in Èkìtì. Drilling in Abẹ́òkúta is not the same with drilling in Ifo. Drilling in Sagamu is different from the one in ikorodu. Even in the same neighborhood, drilling is not the same.

You would have seen cases where the house beside you will have more than enough water and you will be struggling to get your tank full.

This is where geophysics comes in. Geophysics is there to save your money and also prevent any form of accident or loss while drilling. Geophysics is what foundation is to a building. So utmost care most be given here.

I will post some typical results of depth sounding shortly.

Before depth sounding is done, the first thing is to do a profiling. There is a traditional way of doing this using the dowsing rod. Some people called it water witching but it's not. There is a science behind it!

I dnt have a clearer picture, but I have taken up some materials and articles about this subject and I am a little convinced about the postulated science.

Anyway, this device is said to help determine sections or portion on one's plot where groundwater could be found. Although, this does not strikes out need to carry out further exploration works but it could serve as a guide for further exploration.

However, it is my advice that Geoscientist or explorers should not completely depend on this means for sitting a borehole drilling point.

While using this machine, the two long ends tends to cross and make an "X" on locations where there seems to be Groundwater or water bearing zones or features like fractures that could lead to water

For a comprehensive Groundwater Explorations especially in basement complex region where the ultimate Aquifer that is being sought for is fractures (cracks in rocks) it is very expedient to carry out a Electrical Horizontal Profiling using Electrical Prospecting methods (Geophysics) - I am a little sorry for those terms. In simpler words, this means trying to view or picture the horizontal variations that does exist in the subsurface at a particular depth.

Now after profiling, a probable point is selected for further study... i. ẹ depth sounding.
This will help you to know the change in lithologies(sand/clay/limestone /rock unit) with depth. It will also point out the depth your fracture is located.

Drilling is now planned on the knowledge of the different lithologies u r most likely to encounter in the Subsurface.

You can imagine going to field to drill having a mindset of meeting clay or mudstone but getting there and meeting limestone... This is what we called getting shot in the leg.

how can I know the depth of the water.

they say borehole do fail. what makes borehole fail.please how can someone prevent borehole from failing.

@shyyor thanks for d question. Dere r many factors responsible for borehole failure. I will highlight some of them shortly.

Borehole Failure is always a critical issue in borehole drilling industry sometimes this can not be avoided while as professionals efforts can be made to ensure this is reduced to the nearest minimum.

Failures of borehole has man intricacies which may vary from the Geology of the concerned location to mechanical problems on field to human errors and inadequacies.

Some of these are;

hole closure or narrowing

Formation collapse

Poor borehole completion process

Poor maintenance of borehole.

What normally cause collapse is poor grouting /gravel packing or using poor casing. So the load from the formation is just resting on the casing so with time the hole will fail.

Also if a hole is abandoned for long. The hole could fail.

Over pumping of water too can cause hole failure. Most especially when the whole area is tapping from the same source/formation. With time that formation will collapse of your pumping is not controlled.

Also when you don't have the required chemicals to stabilize your hole while drilling. You could lose that hole.

There r so many factors.... Just lemme stop Dere.

shyyor:
how can I know the depth of the water.

The depth you will meet your water will be picked by conducting a vertical electrical sounding also know as depth sounding.

Here are the tools required,
A terameter, 4 point electrodes that will be driven into the ground,
4cables (2 for passing current into the ground, 2 for potential),
a DC source,
2 Measuring tapes,
And of course hammer.

Here is a typical field setup.
This was done recently at a Nairalander site so it has not been drilled.

I will post the result afterwards.

So here is the result from the sounding.

Will be back to explain this.

From the curve, at about 35m, you can see the curve plunging downward with extremely low resistivity. That is typical of a limestone terrain.
The knowledge of geology of the area aided in this interpretation tho.

The geoelectric section explains it further.

So how do you drill in this kind of terrain

How can your service benefit me as a farmer

@sholaw, that's a great question. Am not expecting it any sooner tho.
I have it in mind to talk bout it later so as not to derail from borehole aspect. But now I have to say it.

There is an aspect of geophysics we called agro-geophysics. It's presently in use in countries like Israel, USA, Russia... Only few Nigerians understand its worth and some of them have applied it on their farm.

This new technology helps in checking variations in soil properties rapidly thereby reducing the amount of samples being sent to the lab and so saving cost. It helps you to get a well detailed sampling plan for your farm.

Even with it you might not need further laboratory testing.

The farms we have carried it on are experiencing great and even yield right now.


Attached is a land being prepared for farming.

Here is another technology from our partner in the USA

It's called LandMapper.

Thanks for the clarity, and am so impressed with this. I hope with your help I'll be able to increase my output.

Larwin:
@sholaw, that's a great question. Am not expecting it any sooner tho.
I have it in mind to talk bout it later so as not to derail from borehole aspect. But now I have to say it.

There is an aspect of geophysics we called agro-geophysics. It's presently in use in countries like Israel, USA, Russia... Only few Nigerians understand its worth and some of them have applied it on their farm.

This new technology helps in checking variations in soil properties rapidly thereby reducing the amount of samples being sent to the lab and so saving cost. It helps you to get a well detailed sampling plan for your farm.

Even with it you might not need further laboratory testing.

The farms we have carried it on are experiencing great and even yield right now.


Attached is a land being prepared for farming.

sholaw:
Thanks for the clarity, and am so impressed with this. I hope with your help I'll be able to increase my output.

Yes sholaw, I will pm you now. It will be good to partner with you.

Op, why does some boreholes produce dirty water?

The construction of my house is at roofing level, few weeks ago a water survey on my land shows that the borehole will be dig inside the sitting room which i found it difficult because i cant pulldown what have laboured alot to construct. My question goes thus,what can i do to have a maximum water supply without destroying my sttucture ?

Larwin, your attention is needed!!!

Considering the rate at which people are drilling boreholes in their houses as a means of accessing portable water in this country, is there any threat to the underground water reserve? Is there any law or regulation guiding bore hole drilling because it seems to be the order of the day?

Hardeybiryo:
Op, why does some boreholes produce dirty water?

dirty water is usually due to poor completion of a hole.
It happens majorly in two ways.... surface materials getting into the hole or lose sediments infiltrating into the hole.

Poor completion ranges from grouting to casing and installation of pump.

If these three are not done properly then there is high possibility of getting a dirty water.

Grouting is a critical step in borehole completion. It's function is to prevent surface infiltration or Pollution and at the same time prevent the already weaken wall of the formation from caving in. It's done using cement or gravel packing. Different field warrant different use.

Casing is also another issue, the types of casing u use depends on yr hole condition and geology.

And the use of pump is a function of the hole pressure and yield. If your pump is too powerful than what it suppose be, it will at a time weaken the formation your tapping water from and in the long run you will be seeing sediments in your water.

This is the reason why we at Dextol Global Geophysicals always advice our potential clients not to look at the cost they will spend on getting a borehole but to look at the professionalism and honesty.
Looking for cheap borehole is just like looking for poor hole completion.

Even your hole might not be properly cased down where the need be. People just have to wake up and stop falling victims. Pay a standard price and you will get a standard hole. It's not always about getting water, it's about your hole serving you and lasting without any problem.

Thanks

tushantuna:
The construction of my house is at roofing level, few weeks ago a water survey on my land shows that the borehole will be dig inside the sitting room which i found it difficult because i cant pulldown what have laboured alot to construct. My question goes thus,what can i do to have a maximum water supply without destroying my sttucture ?

This is very funny, well this is part of the reason we always advice builders to do the survey first.
Am very sure there will be another point you can drill. Although this might be difficult to locate due to probably obstructions from development that has taken place.
What you need is a more detailed study and even integration of methods to get a more desired point. This might cost you more. You can pm me, we ll guide you right.

tunazee:
Considering the rate at which people are drilling boreholes in their houses as a means of accessing portable water in this country, is there any threat to the underground water reserve? Is there any law or regulation guiding bore hole drilling because it seems to be the order of the day?

Wow, what a question. Well we just have to thank God for where he put us. Naturally there is no threat to the reserve, but tapping the reserve could pose a threat.

Nigeria is situated on a stable plate(not active) which means we r still safe. I don't want to go too technical here.

But Those on the sedimentary terrain like Lagos are likely to encounter something like subsidence in the nearest future if the indiscriminate drilling of holes continues.

So far there is no law guilding drilling in Nigeria. We only have associations

abimbawealth:
Larwin, your attention is needed!!!

Thanks swt

Interesting information.

Are you able to share with us the cost of conducting a geophysical investigation? Are the charges per day, size of land, or something else?

How do we avoid "quacks"? Is there an association or society they are members of or receive certification from?

Lastly, can 1 "geophysical investigation" determine borehole depth and recommended foundation for a structure?


This will help us Nairalanders avoid being cheated when in search of this service.

Thanks in advance.

@msogunro, thank you for the compliments. I am so sorry for responding ds late, been busy with projects.

The cost for geophysical investigations varies from place to place and projects, however, our range as a company falls within 20k - 50k. Sometimes we go as far as integrating various geophysical methods in prospecting for our desired interest in the Subsurface. You can inbox me privately for more clarifications or deals.

"Quacks" as a subject is the problem of every profession here in Nigeria except if we only want to hide from the truth, our industry is not exempted in this as well. The resultant effect of their involvement have led to the increased Failures that is being observed everywhere, although their pricing or quote is always luring especially to clients that would always want to cut costs.

There are Associations and bodies governing the profession some of which are;

Nigerian Mining and Geosciences Society (NMGS) - Headquarters in Jos, plateau state.

A governing council that overseas exploration works and related studies is:

Council of Mining Engineers and Geosciences (COMEG) - they are also saddled with the responsibility of controlling quacks and ensuring competence in various exploration works. COMEG issues a seal or certification to operate as a mining engineer, Geoscientist and related fields.

As clients seeking the service of any of these;

one quick way to sense quarks is their charges - most times, they give very low charges compared to probably the usual market price (I'm as well not in support of outrageous prices) basically because they really do not have the interest of the job at heart but just want to get the job and get their own and leave, not minding their image or future opportunities. Then, they get to use substandard materials and do the job anyhow, some people would even run away after collecting money (just speaking my mind anyway).

Another way of avoiding quacks is to contact registered companies or persons who have sound knowledge in the desired area, even if the person cannot offer the service, such would guide and help recognize the right person for the job. Registered ® companies are always mindful of public image even more than money.

Previous projects - this is another way of avoiding quarks, clients may need to ask the intended company or persons about how they have delivered in such capacities in the past, if competence is proved, the client can go ahead with the project.

To your last question, "YES" - Geophysical investigations would give an idea of the drilling depth that is ideal for a particular site or location. Geophysical investigation also has its applications in foundation studies and other engineering studies. This is the next aspect I intend to shed more light on after trashing the borehole and water well issue, I intend to share my personal fields experiences in the post as well.

Thanks.