Introduction to Petroleum Geology

Disclaimer: While every reasonable effort is made to ensure that the information provided is accurate, no guarantees for the currency or accuracy of information are made. It takes several proof readings and rewrites to bring the quiz to an exceptional level. If you find an error, please contact me as soon as possible. Please indicate the question ID-Number or description because server may randomize the questions and answers.

Geology (GLGY 577-UCAL) Midterm Exam

Some questions have hints and explanations. Click Start to begin.

Start

Congratulations - you have completed Geology (GLGY 577-UCAL) Midterm Exam.

You scored %%SCORE%% out of %%TOTAL%%. With incorrect multiple tries your score is %%PERCENTAGE%%

Your performance has been rated as %%RATING%%

Your answers are highlighted below.

Question 1

What is tight gas? (ID-PGL-10)

A	Natural gas produced from reservoir rocks with such low permeability that massive hydraulic fracturing is necessary to produce the well at economic rates.
B	Natural gas produced from reservoirs after the peak production of the play. In other words, low yield gas produced after production has been in place for a period of time.
C	Natural gas produced from reservoirs that are under very high pressures making it tight and easier to extract.
D	Natural gas produced from reservoir rocks that are interbeded with alternating permeable and non-permeable layers.

Question 2

Which of the following is true? (ID-PGL-44)

A	Computer algorithms for reservoir characterization models heavily depends on the analytical variables as opposed to empirical variables.
B	In Alberta, we commonly find oil-wet rocks in the subsurface.
C	Typically, as you move closer to mountains, frequency of stratigraphic traps increases.
D	In Alberta, lens traps are the most common type of hydrocarbon traps.
E	Typically, as you move closer to mountains, frequency of structural traps increases.

Question 3

Which of the following statement is true about the neutron wireline tool? (ID-PGL-15)

A	A typical tool uses uranium as the energy source.
B	It measures the true density of the material.
C	Typically, silicon has a higher neutron reading than carbon.
D	It measures the slow-down length of neutrons when they interacts with atoms.
E	The thermal phase of the tool uses energy at around 10 eV

Question 4

Most neutron tools use which of the following? (ID-PGL-16)

A	Uranium source
B	Thermal phase of the scatter
C	Electric energy
D	Epi-thermal phase of the scatter

Question 5

In order to correct the depth measurements of cores obtained from diverted or horizontal wells, you must obtain which of the following? (ID-PGL-35)

A	Porosity and permeability of the core.
B	Length of the drill string.
C	Total length of the recovered core.
D	Well diversion trajectory angles.

Question 6

Which of the following drilling mud has the lowest impact on the environment? (ID-PGL-12)

A	Synthetic mud
B	Denial-based mud
C	Acids-based mud
D	Oil-based mud

Question 7

Typically, what is the depth of investigation for deep induction tools (ILd)? (ID-PGL-30)

A	0.5 - 2m
B	2 - 3 m
C	0.8 - 1.5 m
D	1 - 5 m
E	0.5 - 1.5 m

Question 8

The following is a map section created using the Canadian Dominion Land Survey (DLS) method. What is the location number for the X position? (ID-PGL-43)

A	Section 3
B	Section 10
C	Section 9
D	Section 4
E	Section 5

Question 9

Which of the following is true about cementation factor, m? (ID-PGL-24)

A	The m and porosity are directly related to each other.
B	All or other things being equal, as m increases, the prore geometry become complicated.
C	Value of m is independent of the surface area of the pores.
D	All or other things being equal, increase in m will result in decrease in a.
E	All or other things being equal, increase in m will result in increase in formation factor, F.

Question 10

Calculate the geothermal gradient given following information. (ID-PGL-33)
BHT (bottom hole temperature) = 255^o F
Surface temperature = 75^o F
Depth which BHT was measured: 11400 ft

A	~ 0.018oF/ft
B	~ 0.016oF/ft
C	~ 0.028oF/ft
D	~ 0.029oF/ft
E	~ 0.015oF/ft

Question 10 Explanation: 

Usually on exams, you will be required to read some of the values from a wireline well log.

Question 11

Knowing that it is a stratigraphic trap, what is represented by diagram E? (ID-PGL-06)

A	Unconformity trap
B	Fault trap
C	Salt dome trap
D	Lens trap
E	Pinchout trap
F	Anticline trap

Question 12

Fossil fuels are chains of... (ID-PGL-01)

A	kerogen.
B	transitional metals and carbons.
C	inorganic compounds.
D	carbon-oxygen bonds.
E	carbon-hydrogen bonds.

Question 13

Typically, what is the resolution thickness of deep dual induction tools (ILd)? (ID-PGL-29)

A	~ 50 cm
B	~ 1.5 m
C	~ 3 m
D	~ 2.5 m
E	~ 80 cm

Question 14

Thin areas on isopach maps are indicative of which of the following characteristic? (ID-PGL-42)

A	Hills or mountains
B	High concentration of hydrocarbons
C	Low net pay regions
D	Valleys
E	High net pay regions

Question 15

Which of the following provide the best analytical evidence for specific formation properties (eg. type of rock, porosity, etc)? (ID-PGL-13)

A	Gravity readings
B	Wireline well logs
C	Geostatistical models such as kriging
D	Core samples
E	Seismic sections

Question 16

What is the depth of investigation for the deep lateral resistivity log? (ID-PGL-17)

A	~30 to 50 cm
B	~ 1.1 to 2 m
C	~ 1.2 to 1.25 m
D	~ 1.35 to 1.75 m
E	~ 26 to 30 cm

Question 17

If you have multiple possibilities for the line of Ro on the Pickett Plot, what is the best approach for obtaining Sw? (ID-PGL-25)

A	Calibrate the Ro line with the core or well logs.
B	Generate several Ro lines on the Pickett Plot.
C	Use the Ro line that is most centered to the all other Ro lines.
D	Generate the most two extreme Ro lines on the Pickett Plot with the maximum Rt and minimum Rt as your reference bounds.
E	Generate several parallel Ro lines on the Pickett Plot.

Question 18

Given following information, calculate Net:Gross and Sand:Shale values. (ID-PGL-41)
net sand = 15.5 m
shale = 5.3 m
gross thickness = 26.3 m

A	Net:Gross = 59 and Sand:Shale = 29
B	Net:Gross = 59 and Sand:Shale = 34
C	Net:Gross = 0.59 and Sand:Shale = 0.34
D	Net:Gross = 0.59 and Sand:Shale = 2.92
E	Net:Gross = 0.79 and Sand:Shale = 0.34

Question 18 Explanation: 

On the exam you will most likely be given a well log. You will have to calculate the above given values from the log. You should know how to read logs.

Question 19

At what stage during the natural formation of crude oil the cracking take place? (ID-PGL-03)

A	Zone of gas formation
B	Initial burial
C	Catagenesis
D	Diagenesis
E	Unaltered organic matter

Question 20

Given C_H = 0.102 what is the R_H? (ID-PGL-20)

A	0.102 Ωm
B	120.0 Ωm
C	102.0 Ωm
D	9.80 Ωm

Question 20 Explanation: 

R_H = 1/C_H

Question 21

Which of the following fraction has the highest number of carbons per molecule (highest boiling point)? (ID-PGL-05)

A	Diesel fuel
B	Lubricating oil
C	Gasoline
D	Kerosene
E	Residuum
F	Heavy gas oil

Question 22

Which of the following has the best verticale resolution? (ID-PGL-47)

A	Neuron log
B	Gamma ray log
C	Dipmeter log
D	Caliper log
E	Sonic log

Question 23

Typically what would you expect to observe on shale conductivity? (ID-PGL-32)

A	Becomes almost zero with hydrocarbon saturation.
B	Decrease with increase in clay interbedding.
C	Decrease with depth.
D	Increase with sand interbedding.
E	Decrease with increase in hydrocarbon saturation.

Question 24

Which of the following is not an assumption used in Archie equation? (ID-PGL-22)

A	Formation must be clean and free of clay.
B	Oil and gas acts as conduits for electrical signals.
C	Proposity must be the same both above and below the oil-water contect.
D	Formation is completely saturacted with fulids.
E	Resistivity of the formation water is same above and below the contact.

Question 25

Generally what is the reference elevation for core samples taken out of a drilling operation? (ID-PGL-11)

A	Position of the Kelly Bushing
B	Lowest point of the hydrocarbon pool
C	Top of the major formation
D	Bottom of the major formation
E	Highest point of the hydrocarbon pool

Question 26

Typically, what is the vertical resolution of Gamma Ray logs? (ID-PGL-38)

A	~ 10 cm
B	~ 30 cm
C	~ 40 cm
D	~ 80 cm

Question 27

Which of the following is true (scientifically) regrading fracking? (ID-PGL-37)

A	It may result in earthquakes.
B	It will not affect aquifers.
C	It is easier to frack on soft sediments.
D	It is a relatively very new technology.

Question 28

Which of the following statement is true about fromation factor, F? (ID-PGL-23)

A	Porosity and formation factor is directly related to each other.
B	Formation factor is inversly related to tourtousity factor.
C	Pore stucture is directly related to the formation factor.
D	Clean granular formations have a lower formation factor than clean carbonate formations.

Question 29

Regardless of the scale, what can you derive from the following gamma ray (GR) signature? (ID-PGL-49)

A	Coarsening downward sequence
B	Very high gamma ray kick Hint: You need the scale for this interpretation.
C	Net sand content Hint: You need the scale for this calculation.
D	Coarsening upward sequence

Question 30

As a Petroleum Geologist, you often have to make decisions based on limited access to samples and data. Your boss sent you the following image of a core from an unknown location at an unknown depth. Just by looking at the image, which of the following statements would you submit to your boss? (ID-PGL-34)

A	This part of the core is most likely saturated with hydrocarbons.
B	This part of the core is most likely have a very high permeability.
C	This part of the core is most likely have a very low permeability.
D	This part of the core is most likely saturated with organic materials.
E	This part of the core is most likely harder and stronger relative to other areas of the core.
F	This part of the core is most likely concentrated with bitumen.

Question 30 Explanation: 

For this question, multiple answers are possible. You may choose the one with bitumen and hydrocarbons and argue that those answers are correct. However, on multiple choice exams you are expected to choose most suitable answer. Technically you cannot say this is hydrocarbons (HC) or bitumen because by definition, you must satisfy the chemical and physical properties of such materials in order to classify as such. But the term "organic materials" can be used for border range of things including HC and bitumen.

Question 31

Neutron porosity, ΦN is measured to be 15% and the Density porosity, ΦD is measured to be 10% on a sandstone calibrated matrix. It is plotted on the Schlumberger CP-1e as shown below (red circles). What is the true porosity given there is no gas effect in this particular section? (ID-PGL-53)

A	6%
B	15%
C	12%
D	5%
E	10%

Question 32

What is the primary purpose of steam injection into a zone of crude oil? (ID-PGL-09)

A	Increase pressure within the chamber hence driving the crude oil out of the system.
B	Increase the conductivity between pores.
C	Decrease friction between the pore walls and the crude oil.
D	It will reduce viscosity of crude oil hence allowing it to be pumped.
E	Increase pressure within the chamber which facilitate extraction.

Question 33

Which of the following combination most likely result in formation of crude oil during diagenesis? (ID-PGL-02)

A	Proteins and Lignin
B	Carbohydrates, Proteins and Lipids
C	Carbohydrates and Proteins
D	Lignin, Carbohydrates, Proteins and Lipids
E	Lignin and Carbohydrates
F	Proteins and Lipids

Question 34

As resistivity ____ the conductivity ____. Answers are in respective order. (ID-PGL-19)

A	decarses , decrease
B	increase , increase
C	They are not related to each other.
D	increases , decrease

Question 35

Which of the following property would adversely effect measurements and operation of well logging tool? (ID-PGL-28)

A	Directionally focused tools.
B	Low viscosity mud.
C	High concentration of formation fluids.
D	Low mud invasion zone.

Question 35 Explanation: 

Low viscosity mud have two major problems. It may not be able to counteract the formation pressures. Secondly, it will most likely penetrate deep into the formation where formation pressures is too low. Most drilling mud are neither high viscous nor low viscous.

Question 36

What is the first step in petroleum systems "value chain"? (ID-PGL-07)

A	Development
B	Appraisal
C	Production
D	Exploration
E	Reserves Growth

Question 36 Explanation: 

This is supposed to be an easy question.

Question 37

Calculate the sand:shale for the interval between 1000 m and 5000 m on the following Gamma Ray (GR) curve. Assume a sand cut-off of 75 API. (ID-PGL-56)

A	~ 2.81
B	~ 0.20
C	~ 3.50
D	~ 1.76
E	~ 0.71

Question 37 Explanation: 

Net sand interval = 3550 m - 1000 m = 2550 m (read off the GR curve)
Net shale interval = 5000 m - 3550 m = 1450 m (read off the GR curve)
Hence, sand:shale = 2550 m/1450 m = 1.7586...

Question 38

Which of the following geophysical data is cheapest to run? (ID-PGL-50)

A	2D seismic data acquisition
B	3D seismic data acquisition
C	Crosswell seismic data acquisition
D	4D seismic data acquisition

Question 39

The F factor becomes extremely difficult to obtain when... (ID-PGL-26)

A	...the formation is saturated with fresh water.
B	...the formation is low in clay minerals.
C	...the formation is concentrated with clay minerals in saline waters.
D	...the formation is composed of highly complex pore structures.

Question 40

Calculate Sw using the data obtained from following interpreted Pickett Plot. (ID-PGL-58)

A	0.08
B	1.00
C	0.65
D	1.08
E	0.09

Question 40 Explanation: 

Sw = (Ro/Rt)^(1/2) = (0.6/70)^(1/2) = 0.09258....

Question 41

Typically when interpreting wireline well logs, the sand zones will produce _____ Gamma Ray (GR) readings, shale zones will produce _____ Gamma Ray (GR) readings and the threshold value for differentiating between sand and shale is ___. (ID-PGL-14)

A	high , low , arbitrary
B	high , low , at 15 API
C	low , high , at 75 API
D	low , high , at 15 API
E	low , high , arbitrary
F	high , low , at 75 API

Question 42

Which of the following environment would you expect to find most trace fossils? (ID-PGL-40)

A	Point bars
B	Deep marine
C	Tidal flats
D	Beach marine

Question 43

How would you obtain Rw and So maximum from a Pickett Plot? You may use the following diagram to answer this question. (ID-PGL-57)

A	Rw is obtained from the upper limit of the lower boundary (red line above) and So maximum is obtained from the upper boundary (green line above).
B	Rw is obtained from the upper boundary (green line above) and the Sw is obtained from the upper limit of the lower boundary (red line above).
C	Rw is the intersect point between the lower boundary (green line above) and read off the x-values straight down (first brown dash line down). The So maximum is the x-value of the upper most point and read off the x-axis (second brown dash line).
D	You cannot take these measurements from a Pickett Plot. You must use a well log to determine such properties.
E	So maximum is the intersect point between the lower boundary (green line above) and read off the x-values straight down (first brown dash line down). The Rw is the x-value of the upper most point and read off the x-axis (second brown dash line).

Question 44

The Caesium-137 is commonly used as the source for which of the following well logging tools? (ID-PGL-39)

A	Density tools
B	Resistivity tools
C	Neutron tools
D	Gamma Ray tools

Question 45

Which of the following condition would increase the invasion of drilling mud filtrate? (ID-PGL-45)

A	Very high porosity in the formation.
B	Very high permeability in the formation.
C	Very low formation pressures.
D	Very high formation pressures.

Question 46

Which of the following formation factor most likley represent a rock that contains almost all fuild? (ID-PGL-18)

A	F = 0.5
B	F = 0.9
C	F = 0.2
D	F = 2.2
E	F = 0.7

Question 47

Ideal diagenesis of organic matter will result in... (ID-PGL-04)

A	carbon-oxygen chains.
B	reservoir.
C	hydrocarbons.
D	traps.
E	kerogen.

Question 48

Calculate the net:gross for the interval between 1000m and 5000m on the following Gamma Ray (GR) curve. Assume a sand cut-off of 75 API. (ID-PGL-55)

A	~ 0.20
B	~ 4.00
C	~ 0.64
D	~ 3.50
E	None of the answers are correct.

Question 48 Explanation: 

Gross thickness = 5000 m - 1000 m = 4000 m
Net sand interval = 3550 m - 1000 m = 2550 m (read off the GR curve)
Hence, net:gross = 2550 m/4000 m = 0.6375

Question 49

Which of the following frequency can be used in conduction resistivity measurements? (ID-PGL-21)

A	100 kHz
B	20 MHz
C	2 MHz
D	200 Hz
E	2 kHz

Question 50

Fining upwards sequence is associated with which of the depositional history? (ID-PGL-54)

A	Progradating marine shelf
B	Deep marine sediments
C	Progradating delta deposits
D	Fluvial point bar deposits

Question 51

On the following hypothetical geologic map, the black lines are strike lines. When drawing cross sections, the line in _____ can be used as a dip section plane, the line in _____ can be used as a strike section plane, and the line in ____ can be used as an oblique section plane. Answers are in respective order. (ID-PGL-52)

A	orange , blue , green
B	blue , orange , green
C	green , blue , orange
D	green , orange , blue
E	orange , green , blue
F	blue , green , orange

Question 52

What is the difference between a play and a prospect? (ID-PGL-08)

A	The play is an area of interest for petroleum exploration while the prospect is an area within a play that is expected to produce hydrocarbons.
B	The play is an area of interest for petroleum exploration and a prospect is the lowest point on the trap which can hold petroleum.
C	None of these answers are correct.
D	The play is a large area where hydrocarbons may be found, while the prospect is an area where there is a current production in hydrocarbons.
E	The play is an area where common petroleum system characteristics exists, while the prospect is an area where the hydrocarbons can be extracted economically.

Question 53

Seimic data are difficult to obtain when.... (ID-PGL-48)

A	there are multiple sleeply dippinng beds.
B	the beds has no dip, hence almost horizontal.
C	the beds are extremly thick.
D	the seismic signals have to travel through fluids (eg. oceanic seismic).

Question 54

Tortuosity factor... (ID-PGL-31)

A	is highly dependent on the formation factor.
B	is most commonly found to be equals to 1.0.
C	varies between 0.35 and 4.5.
D	is directly proportional to the resistivity.

Question 55

Why would you choose metal casings as opposed to mud casings for top sections of the wells? (ID-PGL-36)

A	To provide support for the Kelly Bushing.
B	To reduce fractures near the neck.
C	To prevent well blowouts.
D	To protect aquifers from contamination.

Question 55 Explanation: 

Usually aquifers are situated close to the surface (relative to the deepest part of the well). Hence using mud may result in cross contamination.

Question 56

The best resistivity data used for identification of lithology are obtained from which of the following? (ID-PGL-27)

A	Rm
B	Ro
C	Rmc
D	Rt
E	Rw

Question 57

Typically which data source would provide the largest area coverage? (ID-PGL-46)

A	3D seismic
B	4D seismic
C	4C seismic
D	2D seismic

Question 58

Which of the following is the most problematic issue with picking a wrong datum? (ID-PGL-51)

A	The key well logs features may not be able to correlate further away from the reference wells.
B	The overall assessment of the geology may be completely wrong.
C	The topography of the area may be distorted.
D	The obvious features of the well logs may be ignored.
E	The calculated net sand volume may be incorrect.

Once you are finished, click the button below. Any items you have not completed will be marked incorrect. Get Results

There are 58 questions to complete.

←

List

→

Return

Shaded items are complete.

1	2	3	4	5
6	7	8	9	10
11	12	13	14	15
16	17	18	19	20
21	22	23	24	25
26	27	28	29	30
31	32	33	34	35
36	37	38	39	40
41	42	43	44	45
46	47	48	49	50
51	52	53	54	55
56	57	58	End

Return

You have completed

questions

question

Your score is

Correct

Wrong

Partial-Credit

You have not finished your quiz. If you leave this page, your progress will be lost.

Correct Answer

You Selected

Not Attempted

Final Score on Quiz

Attempted Questions Correct

Attempted Questions Wrong

Questions Not Attempted

Total Questions on Quiz

Question Details

Results

Date

Score

Hint

Time allowed

minutes

seconds

Time used

Answer Choice(s) Selected

Question Text

All done

Need more practice!

Keep trying!

Not bad!

Good work!

Perfect!

If you get a question wrong, you can still click on the other answers. You have multiple opportunities to select the correct answer. This will open up hints and explanations (if available), which will provide additional information.