Understanding deep geothermal energy
Understanding deep geothermal energy

This free course is available to start right now. Review the full course description and key learning outcomes and create an account and enrol if you want a free statement of participation.

Free course

Understanding deep geothermal energy

4 Locating high-enthalpy geothermal fields

The search for potentially useful geothermal fields focuses initially on locating rocks that have been chemically altered by natural geothermal fluids, as well as looking for obvious surface features of geothermal activity such as geysers and hot springs. Measurements of fluid flow through the field allow estimation of its likely economic potential.

When a promising resource has been located exploration wells are drilled. However, given the high pressures and temperatures typical of a geothermal resource, special precautions need to be taken. For example, once the drill stem penetrates into a zone saturated with superheated water, the liquid will flash to steam as the pressure drops. This is more dangerous than simply venting the 'head' of pressure in an oil or gas field. The well head itself is capped with valve gear to regulate the flow of fluids, and the whole assembly is then 'plumbed' to an electricity generating plant.

Exploration for HDR fields involves checking exposed granites for their content of radioactive heat-producing elements, and assessing subsurface heat production by measuring surface heat flow. Outlining the buried granite intrusions that are targets for HDR development depends on modelling their extent, depth and volume from gravity surveys; granites have a lower density relative to their surrounding rocks, and produce gravitational 'lows'.

S278_5

Take your learning further

Making the decision to study can be a big step, which is why you'll want a trusted University. The Open University has 50 years’ experience delivering flexible learning and 170,000 students are studying with us right now. Take a look at all Open University courses.

If you are new to university level study, find out more about the types of qualifications we offer, including our entry level Access courses and Certificates.

Not ready for University study then browse over 900 free courses on OpenLearn and sign up to our newsletter to hear about new free courses as they are released.

Every year, thousands of students decide to study with The Open University. With over 120 qualifications, we’ve got the right course for you.

Request an Open University prospectus