| Title | Application of Controlled-Porosity Ceramic Material in Geothermal Drilling |
|---|---|
| Authors | Bill LOWRY and Dennis L. NIELSON |
| Year | 2018 |
| Conference | Stanford Geothermal Workshop |
| Keywords | thermite, lost circulation, swelling clays, cementing, diameter reduction, high temperature synthesis |
| Abstract | Down-hole sealing systems are being developed using the Self-propagating High-temperature Synthesis (SHS) process. SHS uses the thermal energy of solid phase metal/oxide (thermite) reactions, supplemented by mixtures of minerals and oxides, to form monolithic ceramic components in place. These reactions are moderated and controlled, self-oxidized, and run to completion under down-hole water pressure. The method is being extended to applications benefitting from intentionally-generated porosity in the ceramic material, including ceramic screen formation. Lost circulation is a common problem in geothermal drilling and is often mitigated using Lost Circulation Materials and/or cement. However, these options are often not successful. A ceramic plug can be emplaced at the LCZ and the reaction initiated. The plug will then penetrate the zone and form an impermeable barrier. It can then be re-drilled within hours minimizing non-productive time. In a similar fashion, ceramic plugs can be used to mitigate sloughing of borehole walls caused by swelling clays, weak formations and differential stress. Lost circulation and borehole instability may require the premature use of a casing string that can reduce a well’s completion diameter and therefore production capacity. We have performed an extensive program of laboratory testing, and we have begun field trials that are expected to continue this year. This technology has application in conventional large diameter boreholes as well as slim holes. |