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42 Cards in this Set

  • Front
  • Back

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

Whale Oil became too expensive to produce.

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

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

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

Transportation, Refining, Production of Petrochemicals

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

>Source rock (and maturation)

>Migration path

>Reservoir rock


>Trap (structural/stratigraphic)

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

Type I: marine, oil prone

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

Type III: woody and plants are gas prone

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

Small Grain size

Anoxic conditions (To stop degradation of organic matter)

High Sedimentation rate

Define Primary, Secondary and Tertiary Migration

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

Define "reservoir rock"

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

Define "Seal rock"/"Caprock"

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

Define "Trap"

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!



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

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

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

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

What Purpose does the drill mud serve?

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

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

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.

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?

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

Differentiate between TD, MD, and TVD.

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

What can mudlogging tell us?

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

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

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

What are the limitations to core data from a well?

Expensive and time consuming!

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

Differentiate between TBT/TST, TVT and TVD

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

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

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

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

Darcy's law states that permeabiliy, K=

K=(vμΔx/ΔP)= Qμ/A*(L/ΔP)=(QμL/AΔP)


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

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

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

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

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

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

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↓

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

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

Differentiate between Drilling Geometrically and Geologically

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

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

Depositional- bedforms to dune scale, also bioturbation apparently

Diagenetic- cementation

Structural- Faults!

What are the three types of Traps?

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

Differentiate between Absolute sea level VS relative sea level

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

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

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

What are the pros and Cons of Wireline VS LWD


Precise well placement and useful in geosteering


Drilling mechanics affect the measurements

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


Can go deeper


Larger borehole effects

Lots of time between drilling and measurements

Cannot do horz or deviated wells

Define Toplap.

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

Define Onlap.

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.

Define Downlap and Offlap.

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

What is the Fluvial Equilibrium profile?

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

Differentiate between conventional and Unconventional reservoirs.

Conventional: Clastic and carbonate (can use traditional methods)

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

What does an isopach map show?

What does an Isochron map show?

What does an Isochore map show?

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.

Define "crest" with reference to traps

Crest is the highest point of a trap unit

Define Spill-point:

Lowest point of a trap where hydrocarbons are still contained

Define Reserve and differentiate it from reservoir

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.

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

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