Dr. Martin O. Eduvie National Water Resources Institute Kaduna 1 Minimizing the Risk of Borehole Failure by Dr. Martin O. Eduvie.

Minimizing the Risk of Borehole Failure by Dr. Martin O. Eduvie

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Mininizing the Risk of Borehole Failure

Dr. Martin O. Eduvie National Water Resources Institute Kaduna


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When a borehole is not producing the required yield for the purpose of which it is expected to serve or constructed.

Abortive borehole Collapse borehole Producing dirty water Contaminated borehole Saline water intrusion Reducing water and siltation of borehole

What is Borehole Failure


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Planning Investigation eg basic geological,

hydrogeological investigations and geophysical

Drilling – mobilization, materials, site plan and rig set up and drilling

Right methods and good identification of aquifers

Completion process

Process of Minimizing the risk


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Geological and Hydrogeological studies Geophysical surveys (electrical resistivity

using both profiling and VES Good interpretation of Data Borehole drilling – Site rig set up,

identification of aquifers through 1. Sample inspection and analysis eg

penetration rate, grain seize analysis, observation process,

Steps by step


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Geophysical well logging (Electric SP and PR, gamma logs and Caliper

MaterialsEnsure that right are used e.g casing and

screen, gravel pack and good grouting

CompletionWell development eg airlifting and jetting

Geophysical well logging


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Constant discharge Step test Analysis of pumping test data Recommend appropriate pump based on

aquifer characteristics Water quality analysis

Pumping Test


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GROUNDWATER EXPLORATION METHODS

Geophysical surveying – using EM34 equipment at Kabale, Tanzania

Drilling a borehole for groundwater using a Schramm down the hole hammer system, Tanzania

BGS©NERC June 2002

BGS©NERC June 2002


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Tanzanian hydrogeologist analysing drilled rock chip samples

Rock chip samples presented in a half tube as a pseudo-core showing reddened oxidised near surface material at left

passing through to non-weathered grey material at right, with weathered orange

band at depth at far right

Core of grey fractured meta-shale showing

narrow calcite infilled fracture

ROCK SAMPLES OBTAINED DURING DRILLING

BGS©NERC June 2002

BGS©NERC June 2002

BGS©NERC June 2002

Processes during Drilling, Sample Inspection & Pumping Test

Samples inspection

Minimizing the Risk of Borehole Failure by Dr. Martin O. Eduvie 9


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Idealized Log Chart showing typical Logs and theirHydrogeologic Interpretation

SP RESISTIVITY GAMMA RAY

HOLE CALLIPER

HYDROGEOLOGICINTERPRETATION

SN 16”LN 64”

Dry Sandsome caving

Clay, homogeneous

Sand,Saline water

Clay,Sand streaks

Freshwater Sand

Clay

Sand,Brackish water


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Borehole Casing In progress.

Hydrogeological Data records


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Borehole logging to produce productive boreholes


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RECORDING DATA DURING TEST PUMPING

Measuring the water level during a pumping test at Mangochi East, Malawi

Measuring the discharge rate during a low yielding pumping test at Oju, SE Nigeria

BGS©NERC June 2002© WSP-AF


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The report must highlight the following: Executive Summary Introduction – Client, location with coordinates

and purpose Logging techniques and data acquisition

methods Logger used with all calibrations. Interpretation with details of borehole design

with diagrams Conclusions and recommendations

Report Writing


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The information gathered during drilling boreholes and construction of wells is valuable and should be documented.

Before leaving the site it is important to compile the following information

Borehole number, Name of the village and location of borehole with GPS coordinates

Location of the borehole or well, matched to the Initial geophysical surveys A sketch map of where the borehole/well is located in relation to prominent

features Dates of construction, and activities carried out on daily basis The depths and type of drilling methods used. For example 8 inches tricone

bit to 20m depth, Down the hole hammer bit from 20m-40m Main water strikes and static water level The drilled diameters ,position of screen and casing Position and size of gravel pack ,depth of seal Length and type of development. Lithological descriptions of samples Any other relevant data/information

Contents of well completion report


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The information above can be used to produce a short report on the borehole with all the necessary summary information

Reports usually contain the following information: A summary of the borehole/well details A summary of the drilling information A diagram showing the construction of the borehole A diagram showing the lithology of the borehole with water

strikes Analysis of pumping test data as well as the result of the test Result of water quality analysis Recommendations as regards the type of pump to be installed,

treatment required(if necessary) and other things the client need to be aware of.

WELL COMPLETION REPORT CONTD.


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Report writingThe following key points should be reflected in the report.

1. Name of the village and location of borehole with GPS co-ordinates

2. Location of borehole or well, matched to the initial geophysical survey3. Dates of construction, name and roles of all those involved4. The depths and types of drilling methods used 5. Penetration times and static water level6. Drilled diameters, position of screen and casing7. Position and size of gravel pack, depth of seal,8. Length and type of development9. Lithological description of chip samples

REPORT WRITING


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Report should also Contain the Following・ A summary of the borehole location details・ A summary of the drilling information・ A diagram showing the construction of the borehole・ A diagram showing the lithology of the borehole with water strikesThis drilling report is usually added to the village file along with other technical information such as geophysical and village surveys and the results of hydrogeology at the site forms the building blocks for understanding how groundwater resources occur in an area.

REPORT WRITING CONTD.


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AN EXAMPLE OF DRILLING LOG

8''1/2

16.63

7

19

Surfacecasing

22"(2.4m)

14''(7.5m)

7.35

4.10

8

10.60

11

20m

+ +

++ +

+

++ +

20m

DTH

greenishgrey ~

brawnishgray

1st+ +

+ +

++ +

+

BrownishGray

15m+

+ 13

slightly weatheredGranitic fine Gneiss

+ ++

+ +

Gravel with Sand

+ +

10

7.5○

weathered Gneiss++ +

+

GravelPacking

10m+ ++ 9

15m

+ +

+ +

5m

10m+

6

○○ ○

○ ○

Sealing

Drilling

Grout

20''

(inch)

Midium ~ coarse Sand Brownish

2.60m

Brownish

Description of L ithology ColorWaterlevel

5m

GravelPacking

CasingProgram

Wing Bit

DiameterDepth

(m)

Well Structure

Log

Electrical LoggingDrilling Spead (min/m)

BrownishGray-White

Depth(m)

Lithology Data

1 Top Soil Black

3fine ~ medium Sand

0 50 100


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An example of Well Construction DataDATA OF THE WELL

Borehole No. Village Name Coordinate Altitude T. A. District Country

Date Drilling : RIG Model Method Fluid Surface hole Final depth Casing depth Final diameter

15-Sep-06 16-Sep-06 BIAC RCD DTH air 17.0m 41.0m 41.0m 215.9mm

Casings : Type ID OD Joint Type Position (m): +0.5 -26.10; -38.1-41.0 TotalPVC 101.0mm 113.0mm Socket 29.5m

Screens : Material OD Slot size Open ratio Joint Type Position (m): -26.1-38.1 Total

PVC 113.0mm 0.8mm 9.34% Socket 12.0m

Gravel pack Origen Size Position (m) Volume Pumping Test S. W. L. D.W.L. Discharge rate: Specific Capacity

SALIMA ø 1-5mm -20.0-41.0 792.0 lits GL -5.09m GL -23.00m 70.0 lits/min 3.91 L/min/m

Hand pump : AFRIDEV Setting depth : 20.955 m Pump position: GL -26.00m

Diameter (mm)& Method

Borehole structure Lithology

LEGEND:

TR = Tricone WB = Wing CG = Cement Grouting CP = Casing Pipes

HB = Hammer bit BF = Backfilling with Cuttings SP = Screen Pipes

MR = Mud Rotary AR=Air Rotary GP = Grava Pack P = Pump

DTH = Down-the-hole Hammer BS = Bentonite seal RP = riser pipes

BF BF

Yieldlit/min

0 50 100

4.0 m

Scale multiply by 10

Scale multiply by 1

BF BF

4.0 m

GP GP

GP GP

B.S.

CG CG

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

-100 0 100

SP (mV)

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

0 50

N-Gamma(cps)

Penetrationrate

min/m0 15 30

WB: 330.2AR

HB:215.9

DTH

20.0 m BS

41.0 m

CP

17.0 m

Gneiss, grey, moderately to slightly weathered

26.1 m

CP

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

0 250 500

16 in Normal

64 in Normal

Water strike

Top soil , dark brown

38.1 m

SP

41.0 m

Gneiss, brownish grey, highly weathered with gravel

16.0 m

Mica clay, brownish grey

41.0 m

RP

P

37.0 m

Laterite, reddish brown

1.0 m

Water strike

Water strike

Water strike


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An Example Of The Pumping Test Data

RESULT OF STEP-DRAWDOWN TEST

Step DurationYield

QYield

QPumping water

levelDrawdown

sSpecificcapacity

(hours) (lit/min) (m3/day) (m) (m) (m3/day/m)

1 1.5 30.00 43.20 11.62 6.53 6.62

2 1.5 50.00 72.00 16.82 11.73 6.14

3 1.5 70.00 100.80 22.32 17.23 5.85

Critical pumping rate (CPR) >70 (lit/min)

Preferable pumping rate >56 (lit/min)

STEP-DRAWDOWN TESTB/H No. LW1-100

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

20.0

0 50 100 150 200 250 300

Time (min)

Draw

dow

n S

(m

)

1-Step : 30.00 l/min



S-Q curve (Log-Log) ; B/H No. LW1-100

1

10

100

10 100 1,000

Yield (m3/day)

Draw

dow

n (m

)


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Final summary of diagram in the Borehole completion report


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Compilation of all borehole reports in a larger data base

It could be from other sources Internal reports External reports MUST be credible

Data Base Management


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1. Well inventory of the

corresponding area

2. The data files for each borehole

BH1 BH3 BH2

BH4 BH6 BH5

BH7 BH8 BH9

BH1

BH2

BH3

BH4

Refer

Update

Component of the well inventory managementWell Inventory Management is consisted by two major components as follows;1.Well Inventory of the Corresponding Area2.The data files for each boreholeFigure shows the figure of the concept of these two component relations. Referring those two components enable to make the effective monitoring plan.

Well Inventory of the Corresponding Area” is consisted by the information of all boreholes in the area such as “ well ID ” , “Location taken by GPS “ , “Name of the village “ , “Type of the handpump “ , “The depth of the handpump “ , “Year of the construction “ , and so on. “The data files for each borehole” is formulated one folder for one borehole. The contents of this folder are the following information.Well Construction dataPump installation dataWater Quality dataMonitoring data

WELL INVENTORY MANAGEMENT


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National Rural Water Supply and Sanitation Programme

[State Level]

-Keep inventory of water supply and sanitation facilities in all

communities and a RWSS database (including quality and well

logs of all boreholes drilled in the state)

[Federal Level]

-Develop a national database for RWSS Project.

[LGA Level]

-Keep an inventory of water supply and sanitation facilities in all

Communities and monitor their operation status

-Monitor the availability of spare parts

Goal of the Well Inventory ManagementNational Rural Water Supply and Sanitation Programme :A Strategic Framework (March 2004) describe the expected role to play of the each organization (Federal, State, LGA, Community) with regards to the well inventory management showing figure ?-?. This is regards as final goal of Well Inventory Management.

GOAL OF WELL INVENTORY MANAGEMENT


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An Example Of Well Inventory At LGA Level

Rural Water Supply System Inventory

LGA name : KADUNA

N E

1 10046.543' 007040.626' Angwangajilo Indian Mark II unknown 1992 2009 repaired by NGO

2 10048.245' 007040.951' Turunku Indian Mark II unknown 1992 2009 repaired by NGO

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RemarksCoordinationSerial

No.Village name Type of pump

Depth ofpump

Constructionyear


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A national or regional level database of all borehole drilling records should be established and kept up to date. If no such national database exists, sector stakeholders should keep and archive records of all borehole drilling work undertaken until it is established

The data from all drilling programmes and projects in the country should feed into this database

Data from the database should be made available free of restriction

There should be transparent sharing of key information on drilling programmes by Governments, NGOs and other stakeholders

DATA BASE AND RECORD KEEPING


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The cumulative knowledge of groundwater resources provided by adequate and accessible data achieves greatly enhances the chances of successful drilling and borehole construction

Information from dry and unsuccessful boreholes is just as important as that from the successful ones.

Government and private drilling companies should be encouraged to enforce data gathering.

DATA BASE AND RECORD KEEPING


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Water Well Reference No: Owner:

Location : Community: Address:

Coordinates Lat: Long: UTM :

Well Permit No. Date Issued: Issuing Authority

State: LGA:Name of Driller: Driller’

s License No:

Drilling Casing

From To Diameter From To Material/Thickness

Diameter

M m mm m M Mm

ScreenFrom To Diameter Type Material Thickness Slot Size Open AreaM m mm Mm

Gravel / Cement GroutFrom To Material Size Thickness Remark

Water WellCap Y/N Cement Slab Thickness Size

Alignment/Verticality Test Remark

General Remarks

WATER WELL CONSTRUCTION DETAILS


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Water Well Reference No: Owner: Location : Community: Address:Coordinates Lat: Long: UT

M :

Well Permit No. Date Issued: Issuing Authority

State: LGA:Name of Water Analyst: Labor

atory:

Constituents Unit ConcentrationSuspended solids mg/l Colour TCU Turbidity NTU TDS mg/l pH

Hardness (CaCO3) mg/l Calcium (Ca) mg/l Magnesium (Mg) mg/l Sodium (Na) mg/l Potassium (K) mg/l Chloride (Cl) mg/l

Total Alkalinity mg/l Bicarbonate mg/l Carbonate mg/l Sulphate mg/l Nitrate mg/l Flouride mg/l Iron mg/l Manganese mg/l

Zn mg/l Copper mg/l Arsenic mg/l Lead mg/l Aluminium mg/l Cadmium mg/l Cyanide mg/l Mercury mg/l

Ammonia mg/l Hydrogen Sulphide mg/l Faecal Coliform Count/100ml Total Plate Count Count/100ml

Field Measurements Temperature 0C pH

Electrical Conductivity

_________________________________________________ ________________________________________________Name: Water Analyst Signature / Stamp / Date

WATER ANALYSIS REQUEST FORM


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Dr. Martin O. Eduvie National Water Resources Institute Kaduna 1 Minimizing the Risk of Borehole Failure by Dr. Martin O. Eduvie.

Documents

risk of borehole failure

borehole casing

siltation of borehole

eduvie slide

eduvie5 slide

eduvie9 slide

eduvie6 slide

eduvie2 slide