Unit 1 to 5 Flashcards
Why perform a PVT analysis in the lab?
To determine reservoir fluid behavior & properties from oil & gas samples. To simulate what takes place in the reservoir & at the surface during production.
What are the three properties of reservoir fluids that change w/ presure & temperature?
Viscosity, Density, Compressibility
What kind of process describes a sudden pressure drop causes gas to come out of solution, w/c then remains confined w/ oil that is left?
Flash Liberation
What process describes when a gas comes out of solution as pressure is gradually decreased, but is removed from the oil?
Differential Liberation
What are the two processes that describes how gas evolves from oil when pressure falls below the bubble point?
Flash Liberation & Differential Liberation
Which point is the initial reservoir pressure at when the gas cap almost certainly exists that will expand, pushing oil towards the well & increasing the recovery to 40 percent of the oil in place?
The initial reservoir pressure is at bubble point!
IF the initial reservoir pressure is much higher than the bubble point, meaning the oil is under saturated, then the only drive will be monophasic liquid expansion, resulting in better or poor recovery?
Poor recovery
What does it mean when the oil is under saturated?
It contains a littl dissolved gas
What is the main analytical technique used in compositional analysis of reservoir fluids?
gas chromatography
What is one of the limitations of using gas chromatography for analyzing oils ?
Injecting the petroleum liquid into the chromatograph risks polluting the column w/ heavy elements that won’t elute, w/c causes errors in the measured molecular weight & specific gravity of the liquid residue.
what does C3- mean in shorthand notation?
The compound has less than 3 carbon atoms.
What does a successful PVT analysis requires?
Fluid Samples represent the original hydrocarbon in the reservoir.
What kind of sampling when samples of separator gas & oil are collected simultaneously along w/ rate measurements & recombined to form a reservoir fluid sample?
In Surface Sampling Sample
What kind of sampling employs a sampler tool that is run w/ pressure gauge on either wireline or slickline?
Downhole sampling
What is made up of solids, liquids, gaseous hydrocarbons, and has no elemental sulfur?
Petroleum
Is Petroleum found in limestone rock?
Yes
What is the largest component of natural gas that contains atleast 70-90 %?
Methane
What kind of natural gas that is primarily methane found in reservoirs that don’t need extensive treatment for gas to flow to the surface?
Conventional
What is the API gravity of water?
10
What is the H/C ratio of light crude oil?
1.7 to 1.8
What kind of oil requires upgrading before refining and needs an extensive treatment?
unconventional oil
The fraction of crude oils that are insoluble in light alkanes is called?
asphaltenes
in the oil industry, cycloalkanes are called?
naphthenes
In oil industry, alkanes are called?
Paraffins
What is in a mixed base crude?
Considerable amt of asphalt and paraffin
What kind of physical property that is temperature-dependent?
Density
What kind of crude oil that has higher API value but lower density and lower specific gravity?
Light Crude oil
What is the API of light crude oil?
30-40
How are crude oil classified? based on?
Sulfur content
A crude oil w/ low sulfur content is called?
sweet
What are the contaminants in crude oil?
Dissolved H2S, CO2, CH4, chlorinated water, Clays
What is the bench mark for North America in the classification of petroleum?
West Texas Intermediate
In Geographic Origin, which classification has a very light and sweet crude oil?
WTI
What are the properties of Athabasca Bitumen? How about the bitumen in oil sands?
It has an API of 8. Its sulfur content is 5.0 % wt, it has a carbon residue of 13.5%, its nitrogen content is 4000ppm. Bitumen doesn’t come contact w/ sands, it is separated by a water layer. The water layer contains fines and clays and the higher the fines content in water layer, the more problem it is to extract. The sand particles are made of SiO2 (silicone dioxide) and the sand is not oil wet, but water wet.
What do you call the fraction of the crude oil that is soluble in light alkane?
Maltenes
Which property of crude oil does the nature of an actual solvent matter?
Solubility. The higher the alkane chain the higher the solubility.
Is heavy oil more viscous than bitumen?
No, it is less viscous than bitument but more viscous than a typical crude oil.
What are in the oil sand?
Particles that aren’t fuse together w/c contains bitumen, sand clays, water, etc.
The price is lower when the crude oil contains Higher API, lower density and Specific gravity.
False
What is found from quite near the surface to deeper than 10km, complex gas-liquid systems.
Reservoir
Are 10^5 kpa considered as deep reservoirs?
yes
What is pressure equal to in normally pressured reservoirs?
Hydrostatic Pressure
What is the reason for having a hydrostatic pressure?
It is due to a column of water
True or False. Temperature and Pressure increases w/ depth
True
T or F. HC initially present as gas, will seperate into liq. and gas at the surface?
False!!
What is a critical point a phase diagram of reservoir fluid?
It is when bubble point and dew point lines join. Properties of vapour and liquid phase become identical.
What occurs at reservoir temperature that is in between the critical temperature and CriticalCondensationThermal (CriCondenTherm)
Retrograde condensation
What are the variety of chemical species in the Black Oils?
Large, heavy, non-volatile molecules.