Geol 418

Front 1

Why did the Petroleum Industry boom in the west after the 1800s?

Back 1

Whale Oil became too expensive to produce.

Front 2

What constitutes The "Upstream" part of the Petroleum value chain?

Back 2

Exploration, Reserve development and petroleum production (And Transport for LNG. Liquefied Natural gas)

Front 3

What constitutes The "Downstream" part of the petroleum value chain?

Back 3

Transportation, Refining, Production of Petrochemicals

Front 4

What 5 elements are required for a conventional petroleum reserve to accumulate?

Back 4

>Source rock (and maturation)

>Migration path

>Reservoir rock

>Seal/caprock

>Trap (structural/stratigraphic)

Front 5

What are the Three kerogen type's sources and what do they typically mature to?

Back 5

Type I: marine, oil prone

Type II: mix of land and marine zooplankton, oil prone

Type III: woody and plants are gas prone

Front 6

What are the 3 criteria that are required for preservation of organic material

Back 6

Small Grain size

Anoxic conditions (To stop degradation of organic matter)

High Sedimentation rate

Front 7

Define Primary, Secondary and Tertiary Migration

Back 7

Primary Migration: Migration from source rock to a carrier bed or faults

Secondary Migration: Subsequent flow in beds or faults driven by buoyancy or pressure

Tertiary Migration: Flow from one trap to another

Front 8

Define "reservoir rock"

Back 8

A porous and permeable rock capable of producing economic levels of Hydrocarbon when drilled

Front 9

Define "Seal rock"/"Caprock"

Back 9

Impermeable rock that caps a reservoir; not necessarily always present in a petroleum system.

Front 10

Define "Trap"

Back 10

A closed volume of porous and permeable rock where hydrocarbons would be prevented from further movement

TRAP means that there MUST be contained areas; if there’s a seep you still have a caprock but it might not be a trap!

https://www.youtube.com/watch?v=i_kF4zLNKio

https://www.youtube.com/watch?v=EmZvOhHF85I

Front 11

What is the distribution of clastic sedimentary rocks (Like X% sandstones...), and what does this say about petroleum systems?

Back 11

Seds are 75% silt/mudstone and shale, 13% are Carboantes and 11% coarse clastics (sand+conglomerate)

this means ~75% of hydrocarbons come from a conventional source and ~25% (~13+11) come from a conventional reservoir

Front 12

Describe how deep-water drilling is completed, please <3

Back 12

Seabed is soft and squishy so we have to fist "spud the hole" by lowering a casing (cylinder) and drilling to a certain depth. The drillstem must be sealed against here so the drilling mud and the mud log particles can be collected; It prevents mud from leaking out and also stabilizes the ground. Once the base of the casing is reached, concrete is injected down into the stem. Once it has hardened, the drillstem breaks through this and a little bit of the underlying rock. Then a second casing is laid down. AND SO ON <3

Front 13

What Purpose does the drill mud serve?

Back 13

Cools bit and flushes cuttings out of hole

Mud Weight provides downhole pressure and also stops hole from collapsing around drill pipe

additives in mud prevent formation damage (damage to the rocks we are studying is to be prevented.

Development a mudcake or filter cake on the outside of hole; a layer on top of permeable formations so it prevents other permeable formations from taking stuff from the drillstem in or fluid from outside leaking in

Front 14

What does DST stand for ? What are the axes on the plot? What are the things that can be determined from running a DST?

Back 14

DST (drill-stem test) is used for determining the Permeability (K) of a formation.

The axes are Pressure VS Time

You can find out pressure of drilling mud, the formation pressure, the relative productivity and permeability of the formation. ALSO- whether the reservoir is depleting over time.

Front 15

How do you determine the pressure of drilling mud, the formation pressure, the relative productivity and permeability of the formation, and whether the reservoir is depleting over time using a DST?

Back 15

Pressure of drilling mud= Pressure at B

If it evens off into a flat line, the pressure from DE and GH is the formation pressure

Slope during Flow (CD/FG) productivity.

Slope during Shut-in (DE/GH)= Permeability of the formation

Change in formation pressure= reservoir is depleting

Front 16

Differentiate between TD, MD, and TVD.

Back 16

TD = total depth. Like, we drilled and stopped at 1000m depth ALONG the drill profile

MD= measured depth. As in, we drilled down in total to 1000m but now our MD is 500 because we retracted it

TVD= True vertical depth. We have an MD of 500m, but our TVD is only 300m because that's how deep the drill bit is directly into the Earth

Front 17

What can mudlogging tell us?

Back 17

Usually includes ROP, RPM, WOB (rate of penetration, Rotations per minute, Weight on bit)

Tells us a lithology at depth, can also detect hydrocarbons and the nature of those hydrocarbons using a chromatography

Front 18

What are some of the errors that could be present in a mud log? like limits to the data collected?

Back 18

What’s actually falling down as you drill? Not all the cuttings are from the bottom of the hole :/

Could be contaminated by mud even i we try and avoid that

No "big picture," just fragments of what we are blowing through

Front 19

What are the limitations to core data from a well?

Back 19

Expensive and time consuming!

Also we only see a very small chunk so it's difficult to correlate over long distances

Front 20

Differentiate between TBT/TST, TVT and TVD

Back 20

TBT/TST- true bed thickness/true stratigraphic thickess--> literally the actual thickness of the bed.

TVT- True vertical thickness, the thickness of the bead as measured straight into the Earth. Depending on the angle at which you intersect the dipping unit TVT will be greater or less than TBT/TST. If the dip of the bed in question is zero

TVD= the depth of the drill stem as measures striaght into the Earth

Front 21

Differentiate between absolute and effective, and primary and secondary porosity.

Back 21

ϕabsolute=(bulk volume-volume of solid)*100/total volume

ϕeffective=(Interconnected pore volume)*100/total volume

Primary ϕ- Present in original deposition

Secondary ϕ- Due to alteration or diagenesis

Front 22

What law defines Permeability (K), and what parameters are required to define it

Back 22

Darcy's law states that permeabiliy, K=

K=(vμΔx/ΔP)= Qμ/A*(L/ΔP)=(QμL/AΔP)

Where:

v= fluid flow velocity

μ= the dynamic viscosity of the liquid

Δx= the bed thickness

ΔP= Pressure differential

Q= flowrate in unit volume per second

A= the surface area of the block through which the liquid is flowing

L= the length through which we measure K

Assuming only one liquid is in the medium

Front 23

How do sorting and cementation affect tortuosity, and how will this affect Permeability (K) ?

Back 23

as Cementation↑ and sorting ↓, tortuosity↑. as tortuosity ↑, K↓

Front 24

How Do Illite, Chlorite and Kaolinite affect Porosity (ϕ) and permeability (k)?

Back 24

Illite grains will migrate, reduces K more Than ϕ

Chlorite reacts with acid so we can't use acid to stimulate reservoir. also reacts to form gelatinous blobs so it will block pore throats

to reduce K and ϕ

Kaolinite is blocky and takes up space to reduce K and ϕ

Front 25

How does the Porosity (ϕ) siliciclastics generally change as time goes on?

Back 25

ϕ is largely primary and alteration will mess it up!

Acidic water will create secondary ϕ

Burial will cause ϕ to decrease, go generally as time goes on ϕ↓

Front 26

How do the Porosity (ϕ) and permeability (k) or Carbonates generally change?

Back 26

The effects of depth decreasing ϕ is less then it would be decreased if rock is siliciclastics

Diagenesis will mess everything up!

Dolomitization and no other alteration generally means a 13% increase in ϕ

Front 27

Differentiate between Drilling Geometrically and Geologically

Back 27

Drilling geologically you try and follow and formation (so you'd have to deviate as you cross a fault)

Drilling Geometrically you just drill in a certain orientation and you will likely cross several different formations

Front 28

What are three types of flow barriers? Name examples of each type

Back 28

Depositional- bedforms to dune scale, also bioturbation apparently

Diagenetic- cementation

Structural- Faults!

Front 29

What are the three types of Traps?

Back 29

Structural traps, stratigraphic traps, and traps that are both those two things

Front 30

Differentiate between Absolute sea level VS relative sea level

Back 30

Absolute is just where we are in a eustatic rise or fall; relative (RSL) depends on the eustatic (absolute) sea level AND local signals like basin subsidence/uplift and sedimentation rates

Front 31

Describe 5 situations involving Uplift And eustatic sea level that lead to a rise in RSL

Back 31

1) Just eustatic sea level rises

2) Only basin subsidence occurs

3)Both the above occur

4)Eustatic sea level falls slower than the basin's subsidence

5)Eustatic sea level rises Faster than the basin's uplift

Front 32

What are the pros and Cons of Wireline VS LWD

Back 32

LWD:

Precise well placement and useful in geosteering

BUT

Drilling mechanics affect the measurements

Not actually measuring to the very bottom cause there’s a bit in the way

WIRELINE:

Can go deeper

BUT

Larger borehole effects

Lots of time between drilling and measurements

Cannot do horz or deviated wells

Front 33

Define Toplap.

Back 33

A termination of strata against an overlying surface mainly resulting in non-deposition. Indicative of the top of an HST

Front 34

Define Onlap.

Back 34

A base discordant relationship where initially horizontal strata terminate progressively against an initially inclined surface

Basically a lower dipping surface overlying a surface with a higher dip

Indicative of a TST.

Front 35

Define Downlap and Offlap.

Back 35

Downlap: a surface where initially inclined strata terminate downdip against an initially horizontal or inclined surface- represents a progradation.

Offlap is the arrangement of strata deposited on the ocean floor during its regression

Only difference between downlap and offlap is that offlap is getting deposited further from the shore and at a lower angle

Front 36

What is the Fluvial Equilibrium profile?

Back 36

an imaginary line along a riverbed "above which"" erosion occurs and "below which" deposition occurs- ths profile change depending on gravity and also where we are in the systems tract cycle

Front 37

Differentiate between conventional and Unconventional reservoirs.

Back 37

Conventional: Clastic and carbonate (can use traditional methods)

Unconventional: Tight O/g sands, Shale O/g coal beds

Front 38

What does an isopach map show?

What does an Isochron map show?

What does an Isochore map show?

Back 38

Isopach maps contour points with equal [____]; can be time, unit thickness...

Isochron maps contour points of equal age (so the top of a formation, for example

Isochore maps contour the thickness of the interval between the OWC (oil-water contact) and the base of the trap unit.

Front 39

Define "crest" with reference to traps

Back 39

Crest is the highest point of a trap unit

Front 40

Define Spill-point:

Back 40

Lowest point of a trap where hydrocarbons are still contained

Front 41

Define Reserve and differentiate it from reservoir

Back 41

A reserve contains recoverable volumes under current economic conditions.

Basically a reservoir that can make money NOW, considering capital costs and exploration costs and production costs.

Front 42

Categorize logging tools from highest resolution to lowest. How does resolution change with depth of investigation?

Back 42

The greater the depth of investigation is, the lower the resolution is.

From greatest to least depth of Penetration
Neutron, GR, desity, Sonic Porosity, Resistivity