Thermal Methods
Thermal recovery is the other features in the NoDoC cost models and simulations that refers to oil recovery processes in which heat plays the principle role. The most widely used thermal techniques are in situ combustion, continuous injection of hot fluids such as steam, water or gases, and cyclic operations such as steam soaking.
NoDoC cost models are grouped the thermal recovery into the following categories:
- Steam Injection
. Cyclic Steam
. Simulation
. Steam Flooding
. Fracture/Conduction
. Stimulation
. Combination with Chemicals
- Hot Water flooding
- In situ combustion
. Forward
. Combustion
. Reverse
. Combustion
. Mining
Steam Injection. Heat is injected into a reservoir to reduce the oil viscosity and, consequently, to improve the displacement efficiency. As a result of improved mobilization efficiency crude oil is expanded and flows easily through the porous media toward the wellbore. The process may involve steam soak that is sometimes called steam stimulation or “huff and puff”. In this process, steam is injected down a producing well at a high injection rate, after which the well is shut in. The injected steam heats up the area around the well bore and increases recovery of the oil immediately adjacent to the well. After a short period of injection the well is placed back on production until the producing oil rate declines to economic limits. The cycle is then repeated a number of times until no additional response to steam injection is observed.
Nitrogen Injection
As previously discussed one of the enhanced oil recovery methods is gas injection. In miscible gas injection, the gas is injected at or above the minimum miscibility pressure (MMP) which causes the gas to be miscible in oil. When flooding by the gas is conducted below MMP it is known as immiscible gas injection. Primary conditions affecting miscibility are: composition, fluid characteristics, pressure, and temperature. One gas employed for these gas injection techniques is nitrogen.
Nitrogen has long been successfully used as the injection fluid for EOR and widely used in oil field operations for gas cycling, reservoir pressure maintenance, and gas lift. The costs and limitations on the availability of natural gas and CO2 have made nitrogen an economic alternative for oil recovery by miscible gas displacement. Nitrogen is usually cheaper than CO2 or a hydrocarbon derived gas for displacement in EOR applications and has the added benefit of being non-corrosive.
NoDoC cost models are grouped the thermal recovery into the following categories:
- Steam Injection
. Cyclic Steam
. Simulation
. Steam Flooding
. Fracture/Conduction
. Stimulation
. Combination with Chemicals
- Hot Water flooding
- In situ combustion
. Forward
. Combustion
. Reverse
. Combustion
. Mining
Steam Injection. Heat is injected into a reservoir to reduce the oil viscosity and, consequently, to improve the displacement efficiency. As a result of improved mobilization efficiency crude oil is expanded and flows easily through the porous media toward the wellbore. The process may involve steam soak that is sometimes called steam stimulation or “huff and puff”. In this process, steam is injected down a producing well at a high injection rate, after which the well is shut in. The injected steam heats up the area around the well bore and increases recovery of the oil immediately adjacent to the well. After a short period of injection the well is placed back on production until the producing oil rate declines to economic limits. The cycle is then repeated a number of times until no additional response to steam injection is observed.
Nitrogen Injection
As previously discussed one of the enhanced oil recovery methods is gas injection. In miscible gas injection, the gas is injected at or above the minimum miscibility pressure (MMP) which causes the gas to be miscible in oil. When flooding by the gas is conducted below MMP it is known as immiscible gas injection. Primary conditions affecting miscibility are: composition, fluid characteristics, pressure, and temperature. One gas employed for these gas injection techniques is nitrogen.
Nitrogen has long been successfully used as the injection fluid for EOR and widely used in oil field operations for gas cycling, reservoir pressure maintenance, and gas lift. The costs and limitations on the availability of natural gas and CO2 have made nitrogen an economic alternative for oil recovery by miscible gas displacement. Nitrogen is usually cheaper than CO2 or a hydrocarbon derived gas for displacement in EOR applications and has the added benefit of being non-corrosive.
