Drilling fluids for geothermal drilling – a Geo Energy Marketing blog post
A recent blog post by Geo Energy Marketing describes how drilling fluids are a critical component to the overall success of a geothermal drilling program.
Geothermal drilling fluids are a critical component to the overall success of a geothermal drilling program. The main purpose of drilling fluids during geothermal drilling is to:
- maintain the stability of the wellbore and provide pressure,
- allow for cooling of the downhole environment and drilling tools,
- clean the borehole from cuttings.
The main type of drilling fluids used for drilling the overburden well sections, where the formation collapse is expected and temperature gradients are high, is based on bentonite. Such fluid types, however, after exposure to temperatures ranging between 150 and 200°C (Otte et al. 1990) experience a sharp increase in the viscosity which might result in dangerous stuck pipe incidents and long non-productive time. Other drilling fluid option, that will provide support to the well and allow for good cutting transport include polymer-based drilling fluids. Polymer additives available on the market today are limited to circulation temperatures of approximately 90°C. It is a common procedure to use mud coolers or cooling towers for lowering the temperature of the drilling fluid being recycled from the well during high-temperature drilling.
For the full article see link below.
Source: Geo Energy Marketing