Unit 1 to 5 Flashcards
0
Q
Why perform a PVT analysis in the lab?
A
To determine reservoir fluid behavior & properties from oil & gas samples. To simulate what takes place in the reservoir & at the surface during production.
1
Q
What are the three properties of reservoir fluids that change w/ presure & temperature?
A
Viscosity, Density, Compressibility
2
Q
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?
A
Flash Liberation
3
Q
What process describes when a gas comes out of solution as pressure is gradually decreased, but is removed from the oil?
A
Differential Liberation
4
Q
What are the two processes that describes how gas evolves from oil when pressure falls below the bubble point?
A
Flash Liberation & Differential Liberation
5
Q
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?
A
The initial reservoir pressure is at bubble point!
6
Q
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?
A
Poor recovery
7
Q
What does it mean when the oil is under saturated?
A
It contains a littl dissolved gas
8
Q
What is the main analytical technique used in compositional analysis of reservoir fluids?
A
gas chromatography
9
Q
What is one of the limitations of using gas chromatography for analyzing oils ?
A
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.
10
Q
what does C3- mean in shorthand notation?
A
The compound has less than 3 carbon atoms.
11
Q
What does a successful PVT analysis requires?
A
Fluid Samples represent the original hydrocarbon in the reservoir.
12
Q
What kind of sampling when samples of separator gas & oil are collected simultaneously along w/ rate measurements & recombined to form a reservoir fluid sample?
A
In Surface Sampling Sample
13
Q
What kind of sampling employs a sampler tool that is run w/ pressure gauge on either wireline or slickline?
A
Downhole sampling
14
Q
What is made up of solids, liquids, gaseous hydrocarbons, and has no elemental sulfur?
A
Petroleum
15
Q
Is Petroleum found in limestone rock?
A
Yes
16
Q
What is the largest component of natural gas that contains atleast 70-90 %?
A
Methane
17
Q
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?
A
Conventional
18
Q
What is the API gravity of water?
A
10
19
Q
What is the H/C ratio of light crude oil?
A
1.7 to 1.8
20
Q
What kind of oil requires upgrading before refining and needs an extensive treatment?
A
unconventional oil
21
Q
The fraction of crude oils that are insoluble in light alkanes is called?
A
asphaltenes
22
Q
in the oil industry, cycloalkanes are called?
A
naphthenes
23
Q
In oil industry, alkanes are called?
A
Paraffins
24
What is in a mixed base crude?
Considerable amt of asphalt and paraffin
25
What kind of physical property that is temperature-dependent?
Density
26
What kind of crude oil that has higher API value but lower density and lower specific gravity?
Light Crude oil
27
What is the API of light crude oil?
30-40
28
How are crude oil classified? based on?
Sulfur content
29
A crude oil w/ low sulfur content is called?
sweet
30
What are the contaminants in crude oil?
Dissolved H2S, CO2, CH4, chlorinated water, Clays
31
What is the bench mark for North America in the classification of petroleum?
West Texas Intermediate
32
In Geographic Origin, which classification has a very light and sweet crude oil?
WTI
33
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.
34
What do you call the fraction of the crude oil that is soluble in light alkane?
Maltenes
35
Which property of crude oil does the nature of an actual solvent matter?
Solubility. The higher the alkane chain the higher the solubility.
36
Is heavy oil more viscous than bitumen?
No, it is less viscous than bitument but more viscous than a typical crude oil.
37
What are in the oil sand?
Particles that aren't fuse together w/c contains bitumen, sand clays, water, etc.
38
The price is lower when the crude oil contains Higher API, lower density and Specific gravity.
False
39
What is found from quite near the surface to deeper than 10km, complex gas-liquid systems.
Reservoir
40
Are 10^5 kpa considered as deep reservoirs?
yes
41
What is pressure equal to in normally pressured reservoirs?
Hydrostatic Pressure
42
What is the reason for having a hydrostatic pressure?
It is due to a column of water
43
True or False. Temperature and Pressure increases w/ depth
True
44
T or F. HC initially present as gas, will seperate into liq. and gas at the surface?
False!!
45
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.
46
What occurs at reservoir temperature that is in between the critical temperature and CriticalCondensationThermal (CriCondenTherm)
Retrograde condensation
47
What are the variety of chemical species in the Black Oils?
Large, heavy, non-volatile molecules.
48
What's the other name for Black Oil?
Low-shrinkage crude or ordinary oil
49
What happens when the reservoir pressure is at the bubble point?
It becomes saturated so the oil can only hold as much dissolved gas as it can, the excess gas goes on top of the reservoir and becomes a gas cap.
50
How come Dry gases doesn't have any liquid forming on either in the reservoir or at the surface?
It's because dry gases don't contain enough heavier molecuels to form liquid at the surface w/c is why its separator in the graph indicates that it is outside the saturated envelope.
51
What is a Semi-solid hydrocarbon mixture?
Bitumen
52
What kind of rock is formed by magma/lava being cooled?
Igneous rock
53
What kind of rock that is deposited on earth's surface in layers, and undergoes buckling or shifting as the result of geological forces?
Sedimentary rocks
54
What kind of rock is excellent in trapping petroleum?
Porous rocks (limestone, sandstone, dolomite, etc.)
55
What process is it when a sediment is turned into a rock under pressure?
Lithification
56
What is the measure of the openings in a rock?
Porosity
57
What measures the ability of a material, in this case rock, to transmit fluid through it?
Permeability
58
what range of milliDarcy is a very good condition of the rock's permeability ?
100-1000mD
59
Why use Hydraulic Fraction?
To increase Permeability. To improve the flow of gas and oil to the wellbore.
60
What are the components of a trap/reservoir?
Porosity and Permeability path to source rock, Porosity to hold the oil, Non-permeability barrier to prevent oil from moving to another location
61
What is a waxy and high molecular solid?
Kerogen
62
What is the conversion of the kerogen formed during the diagenesis into petroleum and gas? and also known as the geochemical stage of formation?
Catagenesis
63
What do you call when most of the organic matter transforms into methane as the burial depth increases?
Metagenesis
64
What occurs when an organic matter has kerogen as one of the products and this occurs in a shallow subsurface environment where the temperature & pressure are near ambient and is also called biogenic stage of formation?
Diagenesis
65
What does coal and Oil turns to in a catagenesis?
Graphite and Methane respectively
66
What are the reasons for the petroleum to migrate through carrier layers and into the reservoir?
Buoyancy, Capillary action, and regional pressure gradients
67
What is the most common and easy to visualize trap?
Anticline
68
What are the two major trap types?
Structural Traps and Stratigraphic Traps
69
What are the subtypes of a structural trap?
Fault Trap and Anticline Trap
70
Define Fault Trap?
Numerous, but small. It causes harm because there's a leak in the seal of a cap rock that allows the flow of petroleum through the fault to the surface, w/c forms an oil seep.
71
How are Stratigraphic Traps formed?
They are formed when the permeability changes within the reservoir bed. ie. reefs
72
What technique that consists of imparting shocks to the surface of the soil & to monitor the reflected waves at different locations.
Seismic Exploration
73
What relies on microseepage and is useful when coupled w/ remotely sensed images & photographs?
Geochemical methods
74
What is another name of Drill core examination that requires drilling of an exploration well.
Well Logging
75
What stage in drilling when you drill surface hole and set the conductor pipe?
Spudding in
76
What four major system does a rotary rig consist of:
Engines, Hoisting system, Rotating system and mud syem
77
What is fluid when pumped but sets into a gel when static (shear thinning)?
Drilling Mud
78
What type of drilling mud that isn't dispersed?
Water Based Mud (WBM)
79
What is OBM?
Oil Based Mud that is also non-aqueous
80
What kind of drilling is also known as slant drilling outside the oil industry?
Horizontal (directional) drilling
81
What is the purpose of Horizontal drilling?
To increase the exposed section length through the reservoir by drilling at an angle. To drill into a reservoir when vertical drilling is difficult. To make it cheaper for drilling by having more wellheads together.
82
What kind of method is used when oil is produced through the natural reservoir pressure or by pumping?
Primary Recovery
83
What drive is it used for primary recovery when reservoir energy is provided by expansion of oil and gas as reservoir pressure drops?
Solution gas drive
84
What drive is it used for primary recovery when primary reservoir energy is gas cap w/c expands as pressure drops?
Gas Cap Drive
85
What drive is it used for primary recovery when the water in the aquifer (water-bearing rocks) expands and moves into the reservoir and displaces the oil?
Water Drive
86
What drive is it used for primary recovery when force of gravity pushes oil out of reservoir into well.
Gravity Drainage
87
What recovery is it when further production can be obtained by injection of gas or water into the formation to increase the reservoir pressure?
Secondary recovery
88
what are the three major types of tertiary recovery?
alkaline flooding, miscible flooding, and thermal recovery
89
How are non-condensable gases removed in the crude oil?
Separated using a baffle tower; often flared in small fields. reinjected into the formation in larger fields.
90
How are LPG and Casing head gasolines removed from crude oil? and why is it necessary to remove it?
In a flasher unit. In smaller quantities they are removed at the refinery. Can cause vapor lock if LPG is present in large quantities.
91
Where and how are dissolved water and free water removed?
dissolved water is removed in refinery cause it is difficult to remove. while free water is easily removed in settling tanks.
92
How are Emulsified water (brine) removed?
Sediments will be removed w/ the emulsified water.
93
what are the four main methods of transport (order of increasing cost)?
Tanker, Pipeline, Rail, Truck
94
Why are pipelines generally operated under turbulent flow conditions?
Velocity of flow across the diameter of the pipe is approximately constant and mixing occurs only at the interfaces bet. different batches
95
What is a laminar flow in the pipeline?
Flow is fatest at the center of the pipe and slowest at the walls of the pipe.
96
T or F. When H2s content is higher than abt 6mg H2S per 1Nm^3 is sweet natural gas?
FALSE! it is sour natural gas
97
What are the uses of natural gas?
Electricity generation, Hydrogen production, Petrochemical industry, and Residential & industrial heating.
98
Examples of unconventional gases?
Shale and tight gas
99
where is Natural gas found?
Gas Fields, Oil Fields(as a gas cap), Oil Fields (dissolved in the oil), Coalbed Methane, and Gas Hydrates
100
What is the issue of high concentration of methane in coal mine?
Safety Issue
101
what is the natural gas that is found in gas fields?
contains significant amt of H2S,known as non-associated gas, may contain H2O, CO2, and He. Conventional and unconventional gas is included.
102
What gas provides the pressure to the oil reservoir and where is it found? and where are dissolved gases found?
Natural gas in oil fields (as a gas cap) and Oil Fields (dissolved in oil)
103
Where do you find natural gas that does frequently not contain H2S?
Coalbed Methane
104
What is clathrate?
Methane gas surrounded by molecules
105
Why does hydrate cause problem?
It plugs in the pipeline. it is unpredicted freezing in lines. Methane Hydrate is stabe at Moderate Pressure and cold temperature.
106
What reservoir contains lower quality products? (Tight gas, shale gas, gas hydrates, CBM)
Larger reservoirs
107
What is a higher ranking coal and is better in adsorbing natural gas? and what is the lower rank coal?
Anthracite and Bituminous coal
108
What regulates the production and disposition of saline water?
Alberta Energy Regulator (AER)
109
what refers to a natural gas reservoir w/ low permeability and is caused by the fine-grained nature of the sediments.
Tight gas
110
Consists on injecting a fluid made of water, a proppant (fine grained solid), and various chemicals into the formation at very high pressure.
Fracing (Hydraulic fracturing)
111
What refers to natural gas in a shale reservoir and is also low permeability that it will not readily release the gas.
Shale gas
112
explain sweetening/treating natural gas.
H2S is treated by using its acid & reacting it with a base (alkanolamine ie. MEA), the amine serves as the base and the OH increases its boiling point
113
How do amines remove H2S and CO2 in a two-step process:
Gas dissovles in the liquid (physical absorption) and Dissolved gas (weak acid) reacts w/ amines (weak base)
114
Why do you reduce pressure in a flash tank of an amine plant?
because dissolved gas leaves amine solution.
115
Why is water removed through dehydration?
liquid water could condense and lead to corrosion while water in low temperature freezes and forms hydrates (methane hydrates) in pipelines.
116
What is the most significant desulfurizing process that recovers elemental sulfur from gaseous hydrogen sulfide?
Claus process
117
Why is liquid elemental sulfur poured into large blocks to solidify?
For long term storage.
118
in the first step of cause process, how much H2S is oxidized?
1/3 of H2S, reducing the oxygen.
119
In a second reaction (catalytic) how much H2S is reacted w/ SO2 formed over a catalyst?
2/3 of H2S is reacted w/ SO3 with an alumina catalyst.
120
Why are the catalytic reactors operated at decreasing temperature?
For good conversion.
