Co-production geothermal energy from oil wells

Co-production geothermal energy from oil wells Oil pumping rig, prairie, Wyoming (source: flickr/ timailius, creative commons)
Alexander Richter 24 Aug 2010

Geothermal energy power generation from co-produced fluids from existing oil and gas wells for geothermal energy is becoming more and more a hot topic.

Having reported on the two day geothermal in the oilfield symposium before, the following summary of the event was summarized by local media in Wyoming, United States.

The article says that “the concept of using geothermal energy for power generation using co-produced fluids from existing oil, gas and industrial infrastructure is a hot topic in the energy generation industries.

Speakers and participants [at the event] from all over the nation from various industries, utilities, academia and companies learned about current and future activities using hot water from oil and gas fields to produce electricity.

The concept is being tested at the Rocky Mountain Oilfield Testing Center (RMOTC) in the Teapot Dome oilfield. The project focuses on oil wells that produce much higher volumes of water than oil, said Jim Nations, RMOTC’s public relations program manager.

Electric pumps are used to extract the remaining oil or gas. The oil and water are separated, and then the water is passed through a heat exchanger that is part of an Organic Rankine Cycle generator.

In the heat exchanger vessel, heat passes from the water (about 190 degrees Fahrenheit) and is used to boil liquid isopentane, a hydrocarbon compound. The resulting isopentane gas spins a turbine connected to a generator, which produces electricity, Nations explained. The isopentane is then cooled, which condenses it back to a liquid state, and is reused over and over again in a closed loop/circuit for the working fluid.

The electricity can be used by the oilfield operator to continue the cycle of extracting the fossil fuels or could be sent to the power grid. There is little or no environmental impact from this process; the oil field infrastructure of roads, wells and power lines are already in place to take advantage of this unique method of power production.

According to Will Gosnold from the University of North Dakota, electricity is the highest expense in extraction projects. Students under his supervision at UND used data from the past 15 years to estimate what the cost savings would be by utilizing geothermal power to generate electricity at well sites.

The conclusion showed that the concept would pay for itself in about seven years. In a 25-year span, the estimates showed that companies could be making an additional $2.5 million over that period by using this model, Gosnold said.

At the RMOTC testing site, Nations said the water is not potable, but it is low enough in total dissolved solids to be discharged into the Little Teapot Creek without further cleanup. The water is collected in ponds before discharge and benefits wildlife and agriculture downstream. The electricity produced is about 220 kilowatts.

“It could be a win-win situation for oilfield operators and energy producers in the future,” Nations said.

At the Casper conference, several speakers described the potential for using geothermal energy in the oilfields in Wyoming, Montana, Colorado, North Dakota, Utah, Texas and Oregon. Others discussed the feasibility and economics in using the concept, the nation’s resource estimates and others.

The first day of the conference was field trips to Alcova to see the area’s different geological formations, including the Alcova Anticline, Tensleep Formation, fractures, different rock types and more. In the afternoon, participants visited the RMOTC site, where a geothermal installation is located and being studied.”

Source: Wyoming Business Report