There are more than 25,000 oil and gas fields in the world. But a great many wells have been abandoned when no longer economically viable. A well may be abandoned after years of oil or gas extraction, or even before it is finished. It has been estimated that there are 29 million abandoned wells worldwide, including at least 3 million in the USA alone.
Decommissioned wells are supposed to be plugged to prevent leaks, but a great many are not. An abandoned well that has not been properly plugged can leak not only quantities of the powerful greenhouse gas methane but also such harmful products as benzene, nitrogen oxides, carbon dioxide. Abandoned wells have been found under schools, near homes and in gardens.
Abandoned offshore wells are likely to spill oil or gas into the ocean, endangering sea life. Corrosion, storm damage, and environmental exposure can make abandoned platforms and wells ticking timebombs.
Find that methane!
Methane is responsible for over 30% of global warming since the start of the Industrial Revolution. While carbon dioxide remains the focus for reducing emissions, the role of methane is now more widely understood. Methane leaks from numerous sources (oil and gas industry, coal mines, landfills, agriculture,...) can now be monitored by satellite.
Reuse of abandoned oil wells
There has been some research into the feasibility of using abandoned oil and gas wells as a source of geothermal energy. Deep existing wells reach down into deep natural heat while saving the cost of new drilling. The retrived hot water can be used for district heating, for example.
Countries where such projects are being pursued include China, Switzerland, Germany, France and Egypt.
References
- Julie Wornan