ACES Successfully Completes Downhole Steam Generator (DHSG) Field Test
Advanced Combustion Energy Systems (ACES) recently announced that it has successfully completed an 11 month field test of it's downhole steam generator (DHSG) called BLACKBIRD. The successful field test was conducted at an East Texas well site where BLACKBIRD has logged over 600 hours delivering over 3 billion BTUs into the pay zone and is now considered in stable production mode.
BLACKBIRD uses Thermoxafication: which is a patented downhole re-pressurization process where steam, CO2 and nitrogen are injected simultaneously into an oil well at high velocity, temperature and pressure for the enhanced recovery of heavy crude hydrocarbons from an oil formation. The hot steam and gas (CO2, N2) are injected at temperatures in excess of 500°F to heat the heavy crude hydrocarbons in the formation, to reduce its viscosity of the oil and re-pressurization of the formation.
On average the recovery factor of reservoirs produced to date is only 25% to 35% of the oil in place with the remainder trapped in the rock. With current technology further exploitation is either too difficult or too expensive. Current surface sited steam-based heavy oil recovery methods are only effective to about 2,500 feet. In contrast, the BLACKBIRD operates in depths up to 20,000 feet. According to a National Institute for Petroleum and Energy Research (NIPER) study, more than half of the 68 billion barrels of remaining heavy oil reserves in the U.S. are below 2,500 feet. Heavy oil reserves below 2,500 feet onshore and at all depths offshore cannot be produced using existing commercial surface steaming technology.
Surface steam generation for injection downhole is generally now required to produce large fractions of these reservoirs. The energy and environmental costs of surface steam injection are substantial. Energy costs of production can consume 20 to 30% or more of the BTU value of the produced oil, costing energy while also generating substantial greenhouse gas (GHG) emissions. Unlike standard surface steam generation, the BLACKBIRD’S combustion occurs entirely underground so that GHG’s will remain underground as well.
BLACKBIRD is designed to be used in existing wells that still contain heavy oil. BLACKBIRD is sized to fit industry standard 5-inch, 6-inch and 7-inch oil well casings and will accommodate standard turning sweeps for horizontal wells, such as steam assisted gravity drainage (SAGD). BLACKBIRD is placed underground through existing vertical and/or horizontal wells and will connect directly to the tool attachment point on the lower end of most commonly used retrievable packers.
BLACKBIRD is for heavy or viscous oil production using 5 and 50 MM BTU/hr. devices offering substantial energy savings compared to current surface steam generators, delivering the entire BTU content of the fuel (including the higher heating value, and avoiding boiler losses as well as surface distribution and wellbore losses). In addition, the combustion products (CO2 and nitrogen, in addition to water) are injected into the reservoir rather than being released to the atmosphere and, if desired, more CO2 could be added for sequestration purposes. Mobile facilities at the well head deliver air, fuel and water to the downhole steam generator.
The ACES system integrates high stability combustion with steam generation in a downhole device attached through an umbilical to surface supply of high pressure fuel, air or oxidant, and water. A 4" OD system is suitable for generating 5 to 50 MM BTU/hr. of heat at 1 to 250 atm. With a barrel of crude oil bringing above $90, such a system allows for high margins to be earned without requiring new well permits. Its’ portability allows for ease of movement and eliminates the risk of locking up capital (in a surface steam system) over a non-producing well. In short, it is a low cost, low risk method for squeezing yields and earning high margins out of existing reserves.
SOURCE: Advanced Combustion Energy Systems