1. REAL-TIME TESTING OF ROCK CUTTINGS DURING DRILLING
Presented by: Irene Ronoh
2018 G2G INNOVATION SEMINAR, PRIDE INN SPA & RESORT
18TH JUNE - 22ND JUNE 2018

2. IRENE RONOH Geologist – Olkaria
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IRENE RONOH
Geologist – Olkaria
Currently enrolled at Reykjavik University for MSc in SUSTAINABLE ENERGY
PGCert. Geothermal Technology (UoA-New Zealand)
PGDip. Borehole Geology (UNU-GTP-Iceland)
BSc in Geology (UoN)

3. Presentation Outline 1 2 3 4 5 Introduction: Conceptual Idea
Challenges/Case studies 2
Opportunities/Proposed Solution 3
Cost Benefit Analysis 4
Recommended Next Steps 5

4. CONCEPTUAL IDEA

5. Introduction: Drilling a well
Collect rock cuttings after every 2m of drilling
INTRODUCTION
Depth of m
50-60 days-Time taken to drill a well
Cost between USD 3-5 million
Cost include drilling services, material and equipment, supervision, infrastructure

6. cont’ Drilling fluid-Aerated mud, Water, stiff foam, air
Rock cuttings carried to the surface by drilling fluid
Smectite clays can present in the cuttings
Expansive structure- swell when too much water is absorbed

7. Case Studies Smectite abundance in the well
Entrapment of the drill string
OW-724V, OW-906, OW-905B and OW-922
Downtime cost per day USD 27,000

8. CHALLENGES OW-724V (2013/2017) 729m-29 days High smectite at 700 m
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CHALLENGES
Six plug jobs to stabilize formation
OW-724V (2013/2017)
729m-29 days
High smectite at 700 m
Stuck at 793 m. Free the string-150 days
Cased and abandoned
Drilling resumed in days
USD 11,541,414

9. OW-906 (2012) TD 2200m-187 days 300 m-Swelling of clays
Downtime-due to reaming, plug job/wait on cement, freeing drill string
Cost of drilling well about USD 7,546,166

10. OW-905B (2013) OW-905B 829 m-135 days 400-700 m- smectite clays
Freeing stuck drill pipes -40 days
Later, plug and abandoned
Cost of well to 829 m about USD 5,058,521

11. OW-922 (2014) 3000 m-89 days Abundant smectite clays 400-600 m
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Use of a dispersant (Calgon) but corroded the drill pipes-Better to anticipate and thus change drilling fluid to stiff foam/ aerated
OW-922 (2014)
3000 m-89 days
Abundant smectite clays m m
Major swelling of clays at 1260 m
Extra 67 days-major downtime
Total cost amounts to about USD 10,939,600

12. Current situation X-Ray Diffractometer (XRD) analysis
After well completion
150 carefully selected samples for clay analysis
Analysis takes 2 months (slow, expensive)
To fast track, outsource the services/ buy and extra machine-more expensive
Process currently affected by slow procurement procedures (Safety badges)

13. PROPOSED SOLUTION
Geologist
Drilling crew

14. Proposed analytical method
Methylene Blue (MeB) Kit
Onsite chemical analyses done by a rig geologist
Cheaper and quicker
Decisions are made when drilling is ongoing

15. How it works Using about 1g of acidified sample
Methylene Blue dye test (MeB Test)
Using about 1g of acidified sample
Add MeB dye progressively until all absorbed
Blue halo indicate saturated smectite

16. COST BENEFIT ANALYSIS Equipment, Materials, Software, Reagents
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COST BENEFIT ANALYSIS
Equipment, Materials, Software, Reagents
O&M costs

17. Training, Safety badges
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Personnel cost
Training, Safety badges

18. DISCUSSION One XRD machine present in the laboratory
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Radiation Protection Board-direct-restricted tendering
DISCUSSION
One XRD machine present in the laboratory
Slow procurement processes during acquisition of X-ray machine parts after breakdown and renewal of X-ray safety badges (Current situation)
Sample preparation and analysis is sluggish hence affecting decision making while drilling
There’s need to detect swelling clays thus advise on appropriate drilling fluid

19. Recommendations
Methylene Blue Dye test to supplement the clay XRD analysis
Decisions on the behavior of the well will be made onsite (while drilling) hence minimize hazards
The cost of Methylene Blue kit is estimates at (Ksh 181,185.94)
Train the geologists and technicians to use MeB Dye

20. JOH-KGN JvW-X1
Thank You