SBIR-STTR Award

A steamflooding/steam generation system is proposed for deep, heavy oil reservoirs. This concept minimizes the downhole heat losses, improves reliability, and reduces the cost of steam generation. Its features will make steaming of very deep wells (below 7500 feet) technically and economically feasible and will improve the economics of shallower well steamflooding. This novel concept supplies heat to the reservoir face with a downhole unit augmented by heated feedwater. The system uses a gas turbine to supply heat and cogenerated electrical power. Phase I laboratory testing will address the key corrosion and operability issues of the downhole unit. Phase II would consist of prototype construction and testing, detailed design of downhole assembly procedures, and longer term performance testing.Anticipated Results/Potential Commercial Applications as described by the awardee:Successful development of this technology could make over 5 billion barrels of U. S. deep, heavy oil reserves physically and economically accessible to recovery by steamflooding or "huff and puff." It could also improve economics of shallower existing or future steamflood projects by adding cash flow from cogenerated peaking power sales to the early years' revenue. Over 10 billion barrels of very deep, heavy, Venezuelan oil could become recoverable by extension of the technology to these high-pressure reservoirs. All of these applications would stimulate presently depressed capital-goods markets for both downhole and surface gas turbine-related equipment and would bolster domestic oil production.

A new techmque for steamflooding Enhanced Oil Recovery (EOR) via downhole steam generation has shown promising results in Phase I testing. The technique uses downhole electric heaters whose sheath materials must withstand hot, corrosive conditions for long times. At least three alloys identified in Phase I have shown acceptable corrosion resistance and no heater failures during 30-day tests at simulated dow-nhole conditions. Furthermore, these tests have included both subcritical, 80% quality steam, and supercritical conditions, indicating possible extensions of steamflooding to greater depths where required injection pressures are above the critical pressure of water. Phase II research will lengthen the corrosion/ endurance monitoring. The Phase II testing will closely simulate the expected commercial power and voltage supplied to the downhole heaters and will use test heaters scaled to simulate the full-size ones. Potentially vulnerable components such as heater joints, brazeto-heater-sheath galvanic couples, and cable-to-heater joints will also be carried through realistic long-term corrosion tests. Testing will encompass both sub- and super-critical steam conditions. The Phase I work also identified some potentially significant interactions between injected high-temperature steam and minerals typical of reservoir rocks. Experiments will be conducted in Phase 11 to quantify these interactions and their effects on heater life and reservoir permeability and inj ectivity. Phase II work will include an economic and field feasibility study. This will give preliminary estimates of economic incentives relative to conventional, above-ground steam generation methods now in practice. Manufacturing or field installation procedures requiring special technique or tool development in Phase III will be identified.Anticapated Results Potential Commercial Applications as described by the awardee:Successful development of the proposed technology could reduce costs in conventional steam-injection applications and make much deeper reservoirs accessible to steaming. It could also stimulate employment and investment in th( presently depressed oilfield equipment, gas turbine, and related heavy manufacturing industries. Finally, it could enhance national security by adding to domestically producible oil reserves.