Archive for November, 2010


Abandoned oil & gas wells and geothermal power

Abandoned oil and gas wells are considered as ‘useless” by oil and gas companies as they do not add to their profit! But these very same wells can be used to generate power thereby reducing the power bills and recovering drilling cost. With pressure mounting on all the countries to reduce carbon dioxide emission and to promote green energy, abandoned oil and gas well are being revisited by the geothermal companies to make best use of such wells by generating electric power.  This way the oil and gas companies can recover part of the cost and the geothermal companies can save drilling cost and  at the same time generate electric power.

 According to a paper presented at the Asia Pacific oil and gas conference and exhibition held in Australia in October 2008 by Lingyu Zhang of Peking University and his co-authors,  several thousands of oil and gas wells are abandoned both offshore and onshore.

 This is true in all the oil producing countries. Indian oil companies does not publicly disclose the number of abandoned wells though such data for other countries are available for scientific analysis.

 Teapot Dome oil fields in Wyoming  uses hot water from stripper wells to generate 132 KWe of electric power using binary double pipe heat exchanger technology. The estimated potential from such wells in USA is about 5000 MWe, according to a paper presented at the American Association of Petroleum Geology by Sullivan and Lopez of Ohio University. Their estimate is that power production from single such well can go as high as 2 to 3 MWe when the bottom hole temperatures reach 232 °C while temperatures as low as 76 °C can also produce electric power through binary technology

 In fact, feasibility test was carried out to generate power from low enthalpy thermal fluids produced in oil wells at Rocky Mountain Oil testing Center (RMOTC).  A binary power plant ( air cooled) was installed  with isopentane as working fluid in 2008. The inlet water temperature was 76 °C and the flow rate was about 5300 L/hr. This unit generated net electric power of 132 kWe till 2009. After a brief gap the unit produced > 132 kWe  till 2010 February.

Generating power from low enthalpy geothermal water using binary technology has a positive impact on oil field economics.  A dying oil well can be rejuvenated if the well is producing hot water.  The binary power plant can provide inexpensive power, saving power bills to the oil industry.  Several economic models have been developed based on oil and water production rate, water temperature, drilling costs, depth of the well and O & M cost. All the models do support economic benefit to the oil industry. The revenue gain depends on the temperature and flow rate of the water

 This clearly demonstrates that oil companies can join hands with geothermal companies to co-generate oil as well as electric power from the oil wells.

 This method is also be applicable to coal mines where underground fire are common.

 India’s current coal  production is greater than 286 million tones. Raniganj coal field is the largest coal mine in India. Like any other coal mines in the world, coal fire in Raniganj is very common. This is true with  other coal mines in the country as well.  For example, several coal seams in Jharkhand and Bihar are burning underground. Coal mine fires are due to primary combustion when oxygen and water are introduced through cracks and unsealed shafts. These coal fires continue through several years  Most underground coal fires exhibit smoldering combustion and may only involve relatively small amounts of coal capable of burning in the presence of small amount (2%) of oxygen.  To give an example of the magnitude of this hazard, in USA there are nearly 600 coal mine fires burning over a period of 80 years. Other under ground coal mines that are burning is located in Russia and in several east European countries.  These fires are located at shallow depth and the depth in many cased do not go beyond 400-500 m. 

Till now this heat energy available is not put to use. Heat exchanger technology commonly used in geothermal power generation can easily be adopted in regions where under ground coal mine fire is common and perennial.  Continuous heat source from burning coal seams underground will provide continuous electric supply. This method controls underground coal fires, controls CO2 emission and generate electric power to million rural homes. We have the know how and need will to implement it!!