8 Flashcards
_____ are used fo define the reservoir boundaries
Delineation wells
_____ are used to optimize resource recovery
Development wells
_____ is ordinarily the first stage of production. It relies entirely on natural energy sources. To remove petroleum from the pore space it occupies, the petroleum must be replaced by another fluid, such as water, natural gas, or air.
Primary production
The natural forces involved in the displacement of oil during primary production are called _____
reservoir drives
• most efficient drive mechanism
• an effective reservoir management trategy for _____ reservoir is to balance oil withdrawal with the rate of water influx
• typically ranges from 35% to 75% of the original oil in place (OOIP)
Water Drive
• gas dissolve in the oil phase at reservoir temperature and pressure is liberated as pressure declines
• recovery by _____ ranges from 5% to 30% OOIP
Solution Gas Drive
recovery ranges from 20% to 40% OOIP
Gas Cap Drive
• is the least common of the primary production mechanisms
• can be effective when it works. It is most likely to happen in shallow, highly permeable, steeply dipping reservoirs
Gravity Drainage
Reservoir Drive Mechanisms
• Water Drive
• Solution Gas Drive
• Gas Cap Drive
• Gravity Drainage
_____ and _____ with reservoir pressure depletion are the most common drives for gas reservoirs
Water Drive and Gas Expansion
_____ can be as high as 70% to 90% of original gas in place (OGIP) because of the relatively high mobility of gas
Gas reservoir recovery
_____ are used as a warehouse for gas. If the gas is used to as a fuel for power plants, it will also meed to be periodically produced and replenish
Gas storage reservoir
what are the performance attributes of a gas storage reservoir?
• verification of inventory
• assurance of deliverability
• containment against migration
The injection of water or natural gas mey be refered to as _____ or secondary production
pressure maintenance
Additional methods may be used to improve oil recovery efficiency by reducing _____
residual oil saturation
The reduction of residual oil saturation requires a change in such factors as
interfacial tension or wettability
What are the methods designed to reduce residual oil saturation?
• Tertiary Production
• Enhanced Oil Recovery
• Improved Oil Recovery
• it occured after waterflooding
• designed to mobilize waterflood residual oil
• designed to improve displacement efficiency by injecting fluids or heat
Tertiary Production
it is often more expensive than just drilling more wells in a denser pattern
enhanced recovery processes
the drilling of wells to reduce well spacing and increase well density
Infill Drilling
Enhanced oil recovery involves
- Chemical
- Miscible
- Thermal
- Microbal
• it includes polymer flooding, micellar-polymer or surfactant-polymer flooding, and alkaline or caustic flooding
Chemical Flooding
designed to improve the mobility ratio and fluid flow patterns of a displacement process by increasing the viscosity of injected water containing polymer
Polymer flooding
uses a detergent-like solution to lower residual oil saturation to waterflooding
Micellar-polymer flooding
• uses alkaline chemicals that can react with certain types of in situ crude
• the resulting chemical product is miscible with the oil and can reduce residual oil saturation to waterfloodin
Alkaline flooding
• include carbon dioxide injection, natural gas injection, and nitrogen injection
• must be performed at a high enough pressure to ensure miscibility between the injected gas and in situ oil
Miscible Flooding
_____ is achieved when interfacial tension (IFT) between the aqueous and oleic phases is significantly reduced
Miscibility
The desired IFT reduction is typically from around ______
1 dyne/cm to 0.001 dyne/cm or less
can be used as the principal injection fluid in a secondary displacement process, or it can be used as the injection fluid for a tertiary process
Immiscible gas
it include hot water injection, steam drive, steam soak, and in situ combustion
Thermal flooding
______ requires compressed air injection after in situ oil has been iginted
in situ combustion
_____ uses the injection of microorganisms and nutrients in a carrier medium to increase oil recovey and/or reduce water production in petroleum reservoirs
Microbal EOR
• an abundant source of methane
• exists as a monomolecular layer on the internal surface of the coal matrix
Coalbed Methane
Coalbed methane is predominantly methane, but can also include other constituents such as
• ethane
• carbon dioxide
• nitrogen
• hydrogen
what are the 3 production performance of a coalbed methane?
• First stage - the reservoir dewaters and methane production increases
• Second stage - methane production
• Third stage - gas rate declines as reservoir pressure declines
the ice-like solid substance is a metastable complex called ______
gas hydrate
the simultaneous flow of natural gas and water in tubing and pipelines can result in the formation of _____ that can impede or completely block the flow of fluids through pipeline networks
gas hydrates
one cubic meter of gas hydrate contains _____
164.6 m³ of methane, equivalent to one barrel of gas hydrate containing 925 ft³ of methane, approximately six times as much gas as the gas contained in an unimpeded gas-filled pore system
the gas in gas hydrates occupies approximately _____ of the volume of the gas hydrate complex
20%
the remaining 80% of gas hydrate complex volume is occupied by _____
water
_____ are those quantities of petroleum which are anticipated to be commercially recoverable from known accumulations from a given date forward (90% probability)
Reserves
those quantities of petroleum which are based on geologic and/or engineering data similar to that used in estimates of proved reserves
unproved reserves
those unproved reserves which analysis of geological and engineering data suggests are more likely than not to be recoverable (50% probability)
probable reserves
those unproved reserves which analysis of geological and engineering data suggests are less likely to be recoverable than possible reserves (10% probability)
possible reserves
it generates a set of cases that yield low, medium, and high reserves estimates
sensitivity analysis
the _____ of a project is the net cash generated or expended on the project as a function of time
cash flow
the discount rate is the adjustment factor, and the resulting cash flow is called the _____
discounted cash flow
the _____ of the cash flow is the value of the cash flow at a specified discount rate
net present value (NPV)
the discount rate at which NPV is zero is called the _____
Discounted Cash Flow Return On Investment (DCFROI) or Internal Rate of Return (IRR)
the concept of _____ applies to either discounted or undiscounted cash flow
payout time
factor to adjust the value of money to a base year
discount rate
value of cash flow at a specified discount rate
NPV
discount rate at which NPV = 0
DCFROI or IRR
undiscounted cash flow without capital investment divided by total investment
Profit-to-Investment (PI) Ratio
NPV equation
NPV = R - E
where:
NPV = net present value
R = revenue
E = expenses
the _____ used in the economic analysis may represent both historical and predicted oil recovery
oil production profile
the predicted oil recovery is used to determine _____
project reserves
several different production profiles maybe required to determine the _____
probabilistic distribution of reserves and associated economic sensitivity
_____ are performed to provide information about the economic performance that can be expected from a project relative to alternative investment options
Economic analyses
economic viability is influenced by both _____
tangible and intangible factors
are relatively difficult to quantify, yet may have a greater influence on the final decision than tangible factors
intangible factors
relatively easy to quantify
tangible factors
example of intangible factors
environmental and socio-political conerns
examples of tangible factors
well costs and reserves
_____ must always be considered when developing a reservoir management strategy
environmental issues
_____ is often in the form or clean-up, such as the clean-up required after the oil spill
Remediation
_____ is a compressibility effect that depends on the geomechanics of the produced interval and its overburden (the change in thickness)
subsidence
what means TBL
Triple Bottom Line
3 goals of TBL
• economic prosperity
• social equity
• environmental protection
cause of carbon dioxide emissions
greenhouse efect
solution to carbon dioxide emissions
storig CO2 in reservoirs
