Conference on

Geothermal Energy Generation

in Oil and Gas Settings

Date: March 13 & 14, 2006

Location: Southern Methodist University, Dallas, Texas

Contact:     David Blackwell

                     Department of Geological Sciences

                     214-768-2745

                     blackwel@smu.edu

 

Who Should Attend:  Geologists & Geophysicists

                                         Reservoir Engineers

                                         Field owners and operators

                                         State and Federal Agency representatives

                                        Researchers

                                        Power Utility representatives

Yesterday’s concept: "Conventional" Enhanced Geothermal Systems (EGS) (+300°F)

Ø      Develop an artificial reservoir, typically near existing geothermal systems (such as in California or Nevada). 

Ø      Several types have been theoretically evaluated. 

Ø      The lack of water is one of the biggest problems! 

Today’s realities: Economic, political, technical and environmental

Ø      High energy prices related to high petroleum prices

Ø      Renewable Energy Portfolio Standards in several states

Ø      Extensive development of deep (hot) oil and gas reservoirs

Ø      Availability of small binary plant technology

Ø      US Energy Bill of 2005 incentives

Today’s concept:

Ø      Water flood fields, example Gulf Coast   [Note - This is the Oil and Gas Journal Article from Sept. 5, 2005.  8 pages (1.3 mb)]

Ø      Birdsville, Australia geothermal system

Tomorrow’s concept: Produced Fluid Geothermal Systems (PFGS) (160-300°F)

Ø      Use geothermal binary plant technology

Ø      Fluid flow from artesian flow or piggy backing on industries producing heated water

Ø      Development of power plant in stages or moveable

Ø      Multiple development scenarios as stated below

 Advantages for O&G Industry/Local Economy/Environment:

Ø      Secondary recovery pays for costs of pumping in water floods

Ø      Technology grounded in practices of hydrocarbon industry

Ø      Utilizes existing infrastructure:  roads, power lines or used locally, etc. 

Ø      Increases financial strength of O&G Companies

Ø      Use of existing petroleum reservoirs and/or modification of them after production ends

Ø      Costs for O&G field development are lower than for start-from-scratch development of EGS (possible payouts in 3-5 years), typical contracts are 10 to 30 years

Ø      Can be scaled, possible to start small and enlarge system as resource evolves

 

Development Scenarios:

Energy conversion is possible at temperatures above 160°F up although efficiency increases significantly above 250°F. Pumping and condensing losses are significant. Condensing is more efficient if cold water is available or as air temperature drops. Well size is a production capacity factor. Geothermal wells are often over 10" in diameter for greater flow rates, a factor for consideration in initial drilling design.

Alternative Production Scenarios - Individual Skid-mounted well head units (200 kw and larger, air or water condensed), or central field units and fluid lines could be used. The huff-and-puff technique could be used for skid-mounted units. In this case local (well head) production and reinjection takes place, and the unit is moved to another field location when ground cooling is a problem.

Water floods - Directly use fluid in a heat exchanger to run pumps, and sell excess power.

Offshore rigs - Run hot oil through heat exchanger, use sea water from below thermocline for condensing to increase generation efficiency.

Hot, fractured gas wells- Produced water is cycled through a heat exchanger. As gas wells are depleted, they would be converted to water by refracturing or by utilizing poor wells in same way. Existing or modified reservoirs could be used. Dissolved gas could be stripped from water if present in sufficient quantities. Detailed pressure analysis needs to be performed to evaluate the pros and cons of operating at pressures above or below hydrostatic conditions.

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