Slim Holes

GEOTHERMAL ENERGY

Exploration Technique: Slim Holes

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• Details
• Activities (29)
• Areas (25)
• Regions (1)
• NEPA(6)

Exploration Technique Information
Exploration Group:	Drilling Techniques
Exploration Sub Group:	Exploration Drilling
Parent Exploration Technique:	Exploration Drilling
Information Provided by Technique
Lithology:	If core is collected
Stratigraphic/Structural:	If core is collected
Hydrological:	Fluid flow and water chemistry
Thermal:	Thermal gradient or bottom hole temperature
Cost Information
Low-End Estimate (USD):	100.00 10,000 centUSD 0.1 kUSD 1.0e-4 MUSD 1.0e-7 TUSD / foot
Median Estimate (USD):	169.89 16,989 centUSD 0.17 kUSD 1.6989e-4 MUSD 1.6989e-7 TUSD / foot
High-End Estimate (USD):	200.00 20,000 centUSD 0.2 kUSD 2.0e-4 MUSD 2.0e-7 TUSD / foot
Time Required
Low-End Estimate:	0.0132802124833997 day 3.635924e-5 years 0.319 hours 0.0019 weeks 4.363109e-4 months / foot
Median Estimate:	0.00998801438274071 day 2.734569e-5 years 0.24 hours 0.00143 weeks 3.281483e-4 months / foot
High-End Estimate:	0.00893655049151028 day 2.446694e-5 years 0.214 hours 0.00128 weeks 2.936033e-4 months / foot
Additional Info
Cost/Time Dependency:	Costs increase with depth over time, and deeper holes require larger initial core size (e.g., Delahunty et al 2012). Cost is also affected by drilling regulations for geothermal test wells, which may require casing string cemented in to a percentage of total depth; these rules typically require 1" cement annulus, which may require reaming of hole to attain.

Slim Holes:

Slim holes are typically drilled using a diamond coated bit, core samples are often collected, and reservoir properties measured. Slim holes can range from 3-6’’ in diameter and be significantly cheaper than traditional wider rotary drilled holes.

Other definitions:Wikipedia Reegle

 

Introduction

"Drilling costs are considered to be the largest expense for developing a geothermal power facility. Slim holes can be a cheaper way to characterize the geothermal resource than traditionally wider exploratory wells (Finger, et al., 1999). Pritchet (1995; 1996) conducted compelling research on the feasibility of small scale geothermal power plants (100-1,000 kWe) using slim holes as production wells to promote remote resource development in undeveloped regions. However, due to the small diameter of slim holes flow rates are not sufficent for large scale power output per well, and are therefore considered to be associated with exploratory drilling." cannot be used as a page name in this wiki.

Drilling costs are considered to be the largest expense for developing a geothermal power facility. Slim holes can be a cheaper way to characterize the geothermal resource than traditionally wider exploratory wells (Finger, et al., 1999). Pritchet (1995; 1996) conducted compelling research on the feasibility of small scale geothermal power plants (100-1,000 kWe) using slim holes as production wells to promote remote resource development in undeveloped regions. However, due to the small diameter of slim holes flow rates are not sufficent for large scale power output per well, and are therefore considered to be associated with exploratory drilling.

 

Use in Geothermal Exploration

"Slim holes are very commonly considered to be synonymous with core holes, however, there can be slim holes that do not recover core samples. Slim holes are usually drilled to recover core, take water samples, measure thermal and fluid flow properties (Garg and Combs, 1993). Once the reservoir has been adequately defined and slim holes happen to be in an optimal location and depth, they can be used for observation and monitoring of the geothermal reservoir during production (Hinchliffe).

Slim holes offer a significant advantage because lost circulation zones can be drilled through with no problems (aside from loss of drilling fluids/mud), without stopping to cure the lost circulation (e.g., Delahunty et al 2012).

Costs increase with depth over time, and deeper holes require larger initial core size (e.g., Delahunty et al 2012). Cost is also affected by drilling regulations for geothermal test wells, which may require casing string cemented in to a percentage of total depth; these rules typically require 1" cement annulus, which may require reaming of hole to attain." cannot be used as a page name in this wiki.

Slim holes are very commonly considered to be synonymous with core holes, however, there can be slim holes that do not recover core samples. Slim holes are usually drilled to recover core, take water samples, measure thermal and fluid flow properties (Garg and Combs, 1993). Once the reservoir has been adequately defined and slim holes happen to be in an optimal location and depth, they can be used for observation and monitoring of the geothermal reservoir during production (Hinchliffe).

Slim holes offer a significant advantage because lost circulation zones can be drilled through with no problems (aside from loss of drilling fluids/mud), without stopping to cure the lost circulation (e.g., Delahunty et al 2012).

Costs increase with depth over time, and deeper holes require larger initial core size (e.g., Delahunty et al 2012). Cost is also affected by drilling regulations for geothermal test wells, which may require casing string cemented in to a percentage of total depth; these rules typically require 1" cement annulus, which may require reaming of hole to attain.

 

Related Techniques

"Core Holes]] are a related technique because they are drilled specifically to recover core samples, while slim holes very often recover core samples. When core samples are recovered they are considered to be the same, utilizing the same drilling techniques." cannot be used as a page name in this wiki.

Core Holes are a related technique because they are drilled specifically to recover core samples, while slim holes very often recover core samples. When core samples are recovered they are considered to be the same, utilizing the same drilling techniques.

 

Field Procedures

Slim holes require less of a footprint for drilling, smaller rig, less water, and can mobilize much quicker than traditional wide rotary holes (Hinchliffe).

 

References

Finger, et al., 1999, http://www.osti.gov/geothermal/servlets/purl/13956/13956.pdf<br:/>Garg and Combs,1993, https://pangea.stanford.edu/ERE/pdf/IGAstandard/SGW/1993/Garg.pdf<br:/>Hinchliffe, http://www.pir.sa.gov.au/__data/assets/pdf_file/0004/127372/Slimhole_drilling_-_Targeting_geophysics-public.pdf<br:/>Pritchet, 1995, http://www.geothermal-energy.org/pdf/IGAstandard/SGW/1995/Pritchett.pdf<br:/>Pritchet, 1996, http://www.geothermal-energy.org/pdf/IGAstandard/SGW/1996/Pritchett.pdf<br:/>Delahunty et al, 2012, https://www.geothermal-library.org/index.php?mode=pubs&action=view&record=1030295

Page	Area	Activity Start Date	Activity End Date	Reference Material
Slim Holes At Alum Area (DOE GTP)	Alum Geothermal Area			GTP ARRA Spreadsheet
Slim Holes At Alvord Hot Springs Area (Combs, Et Al., 1999)	Alvord Hot Springs Area			Slimhole Handbook- Procedures And Recommendations For Slimhole Drilling And Testing In Geothermal Exploration
Slim Holes At Black Warrior Area (DOE GTP)	Black Warrior Area			GTP ARRA Spreadsheet
Slim Holes At Blue Mountain Area (Warpinski, Et Al., 2002)	Blue Mountain Area			Geothermal Resource Exploration And Definition Project
Slim Holes At Blue Mountain Geothermal Area (Fairbank Engineering Ltd, 2003)	Blue Mountain Geothermal Area	2002	2004	Phase I Report U.S. DOE GRED II Program Deep Blue No.1-A Slimhole Geothermal Discovery At Blue Mountain, Humboldt County, Nevada Deep Blue No. 2-A Resource in the Making at Blue Mountain
Slim Holes At Crump's Hot Springs Area (DOE GTP)	Crump's Hot Springs Geothermal Area			GTP ARRA Spreadsheet
Slim Holes At Fish Lake Valley Area (Deymonaz, Et Al., 2008)	Fish Lake Valley Area			Esmeralda Energy Company Final Scientific Technical Report, January 2008, Emigrant Slimhole Drilling Project, Doe Gred Iii (De-Fc36-04Go14339)
Slim Holes At Flint Geothermal Area (DOE GTP)	Flint Geothermal Area			GTP ARRA Spreadsheet
Slim Holes At Fort Bliss Area (Combs, Et Al., 1999)	Fort Bliss Area			Slimhole Handbook- Procedures And Recommendations For Slimhole Drilling And Testing In Geothermal Exploration
Slim Holes At Fort Bliss Area (DOE GTP)	Fort Bliss Area			GTP ARRA Spreadsheet
Slim Holes At Gabbs Valley Area (DOE GTP)	Gabbs Valley Area			GTP ARRA Spreadsheet
Slim Holes At Glass Buttes Area (DOE GTP)	Glass Buttes Area			GTP ARRA Spreadsheet
Slim Holes At Hawthorne Area (Sabin, Et Al., 2010)	Hawthorne Area			Navy’s Geothermal Program Office: Overview of Recovery Act (ARRA) Funded Exploration in CA and NV and other Exploration Projects
Slim Holes At Hot Pot Area (DOE GTP)	Hot Pot Area			GTP ARRA Spreadsheet
Slim Holes At International Geothermal Area, Japan (Combs, Et Al., 1999)	International Geothermal Area Japan			Slimhole Handbook- Procedures And Recommendations For Slimhole Drilling And Testing In Geothermal Exploration
Slim Holes At Jemez Pueblo Area (DOE GTP)	Jemez Pueblo Area			GTP ARRA Spreadsheet
Slim Holes At Maui Area (DOE GTP)	Maui Area			GTP ARRA Spreadsheet
Slim Holes At New River Area (DOE GTP)	New River Area			GTP ARRA Spreadsheet
Slim Holes At Newberry Caldera Area (Combs, Et Al., 1999)	Newberry Caldera Area			Slimhole Handbook- Procedures And Recommendations For Slimhole Drilling And Testing In Geothermal Exploration
Slim Holes At Newberry Caldera Area (DOE GTP)	Newberry Caldera Area			GTP ARRA Spreadsheet
Slim Holes At Reese River Area (Henkle & Ronne, 2008)	Reese River Area			Phase 2 Reese River Geothermal Project Slim Well 56-4 Drilling And Testing
Slim Holes At Salt Wells Area (Combs, Et Al., 1999)	Salt Wells Area	1980	1980	Slimhole Handbook- Procedures And Recommendations For Slimhole Drilling And Testing In Geothermal Exploration
Slim Holes At Salton Sea Area (Sabin, Et Al., 2010)	Salton Sea Area			Navy’s Geothermal Program Office: Overview of Recovery Act (ARRA) Funded Exploration in CA and NV and other Exploration Projects
Slim Holes At Silver Peak Area (DOE GTP)	Silver Peak Area			GTP ARRA Spreadsheet
Slim Holes At Snake River Plain Region (DOE GTP)	Snake River Plain Geothermal Region			GTP ARRA Spreadsheet
Slim Holes At Steamboat Springs Area (Combs, Et Al., 1999)	Steamboat Springs Area			Slimhole Handbook- Procedures And Recommendations For Slimhole Drilling And Testing In Geothermal Exploration
Slim Holes At Steamboat Springs Area (Warpinski, Et Al., 2002)	Steamboat Springs Area			Geothermal Resource Exploration And Definition Project
Slim Holes At Steamboat Springs Area (Warpinski, Et Al., 2004)	Steamboat Springs Area			Geothermal Resource Exploration And Definition Projects
Slim Holes At Vale Hot Springs Area (Combs, Et Al., 1999)	Vale Hot Springs Area			Slimhole Handbook- Procedures And Recommendations For Slimhole Drilling And Testing In Geothermal Exploration

1. Alum Geothermal Area
2. Alvord Hot Springs Area
3. Black Warrior Area
4. Blue Mountain Area
5. Blue Mountain Geothermal Area
6. Crump's Hot Springs Geothermal Area
7. Fish Lake Valley Area
8. Flint Geothermal Area
9. Fort Bliss Area
10. Gabbs Valley Area
11. Glass Buttes Area
12. Hawthorne Area
13. Hot Pot Area
14. International Geothermal Area Japan
15. Jemez Pueblo Area
16. Maui Area
17. New River Area
18. Newberry Caldera Area
19. Reese River Area
20. Salt Wells Area
21. Salton Sea Area
22. Silver Peak Area
23. Snake River Plain Geothermal Region
24. Steamboat Springs Area
25. Vale Hot Springs Area

1. Snake River Plain Geothermal Region

Document #	Analysis Type	Applicant	Geothermal Area	Lead Agency	District Office	Field Office	Mineral Manager	Surface Manager	Development Phase(s)	Techniques
DOI-BLM-CA-170-02-15	EA	Mammoth Pacific	Long Valley Caldera Geothermal Area	Bureau of Land Management	BLM Central California District Office	BLM Bishop Field Office	Bureau of Land Management		Geothermal/Exploration	Drilling Methods Exploration Drilling Exploratory Well Slim Holes
DOI-BLM-NV-B020-2010-0106-CX	CX	Sierra Geothermal Power	Alum Geothermal Area	Bureau of Land Management	BLM Battle Mountain District Office		Bureau of Land Management	Bureau of Land Management	Geothermal/Exploration	Hyperspectral Imaging Magnetic Techniques Magnetotellurics Slim Holes Z-Axis Tipper Electromagnetics
DOI-BLM-NV-W010-2010-0043-CX-2	CX	Geothermal Technical Partners	McGee Mountain Geothermal Area	Bureau of Land Management	BLM Winnemucca District Office	BLM Humboldt River Field Office	Bureau of Land Management	Bureau of Land Management	Geothermal/Exploration	Well Testing Techniques Slim Holes Thermal Gradient Holes Geophysical Techniques
EA-NV-030-07-006	EA	Ormat Technologies Inc	Carson Lake Corral Geothermal Area	Bureau of Land Management	BLM Carson City District Office	BLM Stillwater Field Office	Bureau of Land Management	Bureau of Land Management Bureau of Reclamation	Geothermal/Well Field	Exploration Drilling Slim Holes Thermal Gradient Holes
GFO-04-236b, GFO-10-367		Chena Hot Springs Resort	Chena Geothermal Area	Golden Field Office					Geothermal/Exploration	Slim Holes
NV-063-EA06-098	EA	Sierra Geothermal Power	Reese River Geothermal Area	Bureau of Land Management	BLM Battle Mountain District Office		Bureau of Land Management	Bureau of Land Management	Geothermal/Exploration	Slim Holes Thermal Gradient Holes

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