08123-10

Goal
The short-term goal of this project is to demonstrate the feasibility and benefits of using produced water and a modified waste heat generator to generate electricity for field operations in marginal fields operated by small oil and gas companies. The long-term goal is to spur the wider use of this technology for generating electricity. This technology could lower the cost of electricity for the producing companies, extend the life of some mature wells, and reduce carbon dioxide emissions associated with oil and gas operations.

Performers
Gulf Coast Green Energy, Bay City, TX 77414
Denbury Resources, Inc., Plano, TX 75024
Texas A&M University, Global Petroleum Research Institute, College Station, TX 77843
Southern Methodist University Geothermal Laboratory Dallas, TX 75275
ElectraTherm, Inc., Carson City, NV 89706
Dry Coolers, Inc., Oxford, MI 48371

Background
In this project, Gulf Coast Green Energy will assemble and demonstrate a small-scale, 50 KWh, waste heat generator to generate electricity from produced water at a well site. The electricity can be used on-site or transmitted off-site for nearby field operations. The electrical generation technology operates on heat from the produced water, which preferably is delivered at temperatures above 190 degrees F. The conceptual basis for the technology is an Organic Rankine Cycle (ORC) system. In this system, waste heat enters a heat exchanger and excites a fluid, which drives a twin-screw expander to create electricity. The condensing side of the ORC utilizes fan coolers, which eliminate the need for a cooling tower.

The proposed small-scale of the waste heat generator will allow small producers to utilize their produced water and generate significant amounts of electricity. The researchers estimate that a 50 KWh waste heat generator can generate an equivalent of $43,333 in electricity over a one-year period, at current retail electricity rates. This would permit the operator to recoup the cost of the generator within a reasonable timeframe.

This demonstration project will be a 3-year effort. The research team will select a well for demonstration of the technology from among Denbury’s high water-producing wells in Mississippi. The project will then proceed through equipment design and refitting, field installation of the waste heat generator, startup, field operations, field monitoring, and data collection. The period of operation and electricity generation will be three years, to prove durability of the system and improve industry acceptance of the technology.

Gulf Coast Green Energy will lead the project, with industry support from Denbury Resources, Inc., ElectraTherm, Inc., and Dry Coolers, Inc. Consulting services will be provided by Southern Methodist University Geothermal Laboratory and Texas A&M Petroleum Engineering department. ElectraTherm facility in Carson City, NV will manufacture and test the waste heat generator. Field installation will be performed by Gulf Coast Green Energy and ElectraTherm in close collaboration with Denbury Resources. Dry Coolers will provide the fan coolers for the condensing side of the ORC. Texas A&M and Southern Methodist universities will assist with site selection and data analysis. The main deliverable for the project will be a final report summarizing all technical aspects of the project.

Potential Impacts
If successful, this project could result in 1) reduced electricity costs for small producers, 2) extended life for high water-producing wells, 3) improved environmental performance, 4) opportunities for small producers to trade carbon credits, and 5) use of the geothermal tax credit for small producers, in certain cases.

If producers adopt and implement the concept for generating electricity from waste heat in produced water, it will have positive environmental impacts. This technology will reduce carbon dioxide emissions by producing electricity without burning fossil fuels and eliminate the 9 percent transmission loss that takes place when electricity is imported to a site.

Accomplishments
Work on this project began in October 2009. The Project Management Plan, with a work breakdown structure that concisely addresses the objectives and approach for each task with all major milestones and decision points, and the Technology Status Assessment describing the state-of-the-art of the proposed technology have both been completed.

Equipment was delivered including the Dry Coolers and Green Machine in January 2010 and the Evaporator in February 2010. Engineering on the Evaporator is complete. Additional design work was performed on existing equipment in Edna, TX. The optimization of the fan coolers was solved, and internal components were modified The power factor is being addressed.

Current Status
The project has been completed. The key tasks undertaken are outlined below. The final report is available below under "Additional Information".

Field Equipment Design and Refitting – The design will include a skid-mounted ElectraTherm waste heat generator with a shell and tube heat exchanger installed on a pad of road base material or poured concrete foundation with housing as necessary. The design team will specify a simple bypass 3-valve system to divert the produced water through the heat exchanger and then back into the flow line without creating any adverse effects on production operations.

Field Installation – The research team will determine the optimum location for the waste heat generator, and set up a field team with technical staff from Gulf Coast Green Energy, ElectraTherm, and Denbury Resources to coordinate installation. Subsequently, the team will determine site electrical requirements, prepare a field operations plan, coordinate installation of a bypass system, install the waste heat exchanger and supporting system components, and tune the system performance to maximize the amount of electricity generated.

Field Operations, Monitoring, and Data Collection – Initially, Gulf Coast Green Energy will monitor and tune the waste heat generator with assistance from ElectraTherm (the manufacturer). The team will install a vibration detector on the machine to monitor for bearing failure and perform initial preventive maintenance after 30 days of operation.

Data Analysis and Equipment Maintenance – Gulf Coast Green Energy will monitor field data on scale buildup. The initial cleaning cycle will determine subsequent preventive maintenance schedules to preempt potential problems.

Technology Transfer – Gulf Coast Green Energy will develop and implement an effective program for technology transfer to communicate project results to the industry.

Project Start: October 30, 2009
Project End: April 30, 2010

DOE Contribution: $229,796
Performer Contribution: $229,796

Contact Information:
RPSEA – Martha Cather (martha@prrc.nmt.edu or 575-835-5685)
NETL – Chandra Nautiyal (chandra.nautiyal@netl.doe.gov or 918-699-2021)
Gulf Coast Green Energy – Robin Dahlheim (robin.gcge@gmail.com or 512-517-6793)

Additional Information:

Final Project Report [PDF-1.32MB]