Exploration Technique: Microhole Array
|Exploration Technique Information|
|Exploration Group:||Drilling Techniques|
|Exploration Sub Group:||Exploration Drilling|
|Parent Exploration Technique:||Exploration Drilling|
|Information Provided by Technique|
|Hydrological:||May be possible to assess fluid flow using small-diameter downhole tools designed for slim holes.|
|Thermal:||May be possible to collect limited temperature data using small-diameter downhole tools designed for slim holes.|
|Cost/Time Dependency:||Microholes cost less to drill than traditional wellbores, delivering greater degrees of rock contact per bore with less monetary risk.|
A microhole array is a series of hundreds of small-diameter (<4”) directional boreholes drilled to intersect natural or induced fracture networks in an EGS reservoir. An array of holes is drilled from a primary EGS wellbore and is designed to promote hydraulic communication between the reservoir and injection (and/or production) wells. Multiple microholes allows a larger volume of rock to be accessed by working fluids via more flow paths, increases the probability of intersecting open fractures, and reduces ‘short circuiting’ of working fluids within the EGS reservoir. This results in more effective heat mining of hot rocks, lowering development risk and increasing the productive life of an EGS project.
Microholes are drilled using FLASH Abrasive Slurry Jetting (ASJ) technology using solid abrasives propelled via a supercritical nitrogen, carbon dioxide, flue gas, or steam jet stream. FLASH ASJ has proven capable of drilling all rock types effectively in bench tests, including basalt. Microhole drilling is a completion technique for EGS reservoirs, and is not meant to replace the vertical primary wellbores drilled using traditional techniques.
Bruce E. Galbierz, Kenneth D. Oglesby. 2005. Advanced Mud System for Microhole Coiled Tubing Drilling. Tulsa, Oklahoma: Final Report: US Department of Energy, Bandera Petroleum Exploration LLC, Impact Technologies LLC. unspecifiedp.
David Archibold Summers, Klaus Hubert Woelk, Kenneth Doyle Oglesby, Grzegorz Galecki. Method and Apparatus for Jet-Assisted Drilling or Cutting [Internet]. 03/09/2009. unspecified. David Archibold Summers. [updated 2009/03/09;cited 2009/09/10]. Available from: http://www.google.com/patents/US20090227185
- Ken Oglesby. 04/2013. Microhole Arrays Drilled With Advanced Abrasive Slurry Jet Technology To Efficiently Exploit Enhanced Geothermal Systems. Washington, D.C.. U.S. Geothermal Technologies Office. Geothermal Technologies Office 2013 Peer Review Meeting; 23p.
- Stefan Finsterle, Yingqi Zhang, Lehua Pan, Patrick Dobson, Ken Oglesby. 07/2013. Microhole Arrays for Improved Heat Mining from Enhanced Geothermal Systems. Geothermics. 47:104-115.
No exploration activities found.