61362665 All Exams in One

Ahmed Abd El-Moniem Soliman بالهداية والتوفيق يلدعو ا (4 any Questions 0111822238)

Questions of Petroleum Company

1- Draw both of Western desert, Gulf of Suez and Nile Delta stratigraphic Colum.


2- Draw a simplified map for Egypt with illustrating provinces and cites.


3- Define:

a) Porosity: It is the percentage of pore volume or void space to the total volume of rock. • Primary porosity: The porosity preserved from deposition through lithification. • Secondary porosity: created through alteration of rock, commonly by processes such as

dolomitization, dissolution and fracturing. • Total porosity: is the total void space and as such includes isolated pores and the connected

pores • Effective porosity: The interconnected pore volume or void space in a rock that contributes

to fluid flow or permeability in a reservoir.

b) Permeability: It is the ability of the rock to transmit fluids, to be permeable; a formation must have interconnected porosity (Unit is Darcie) • Absolute permeability: ability to flow or transmit fluids through a rock, conducted when a

single fluid, or phase, is present in the rock. • Effective permeability: The ability to preferentially flow or transmit a particular fluid

when other immiscible fluids are present in the reservoir. If a single fluid is present in a rock, its relative permeability is 1.0

• Relative permeability: is the ratio of effective permeability of a particular fluid at a particular saturation to absolute permeability of that fluid at total saturation.

c) Sedimentary rock: Is a type of rock that is formed by sedimentation of material at the Earth’s surface and within bodies of water. the most important for the oil industry as it contains most of the source rocks and cap rocks and virtually all reservoirs. Sedimentary rocks come from the debris of older rocks ; and are split into two categories: • Clastic rocks: Formed from the materials of older rocks by the actions of erosion, transportation and deposition. (Mechanical process). Such as conglomerate, sandstone, shale. • Non clastic rocks: are formed by chemical precipitation (settling out from a solution). Such as Limestone, calcite and halite.

d) Formation: - It is basic unit for the naming of rocks in stratigraphy: a set of rocks that are or once were

horizontally continuous, that share some distinctive feature of lithology, and are large enough to be mapped.

- Is the fundamental unit of lithostratigraphy. A formation consists of a certain number of rock strata that have a comparable lithology, facies or other similar properties. A formation can be divided into member and are themselves grouped together in groups.


e) Sequence: A group of relatively conformable strata that represents a cycle of deposition and is bounded by unconformities or correlative conformities. Sequences are the fundamental unit of interpretation in sequence stratigraphy. Sequences comprise systems tracts.

f) Index fossil: Are fossils used to define and identify geologic periods (or faunal stages). They work on the premise that, although different sediments may look different depending on the conditions under which they were laid down, If the species concerned were short-lived (in geological terms, lasting a few hundred thousand years), then it is certain that the sediments in question were deposited within that narrow time period. The shorter the lifespan of a species, the more precisely different sediments can be correlated, and so rapidly evolving types of fossils are particularly valuable. The best index fossils are common, easy-to-identify at species level, and have a broad distribution—otherwise the likelihood of finding and recognizing one in the two sediments is minor.

g) Unconformity: Is a buried erosion surface separating two rock masses or strata of different ages. There are many type from unconformity surface: • Angular unconformity: is an

unconformity where horizontally parallel strata of sedimentary rock are deposited on tilted and eroded layers, producing an angular discordance with the overlying horizontal layers.

• Disconformity: unconformity between parallel layers of sedimentary rocks which represents a period of erosion or non-deposition. paraconformity is a type of disconformity in which the separation is a simple bedding plane with no obvious buried erosional surface.

• Paraconformity: is a type of unconformity in which strata are parallel; there is little apparent erosion and the unconformity surface resembles a simple bedding plane.

• Nonconformity: exists between sedimentary rocks and metamorphic or igneous rocks when the sedimentary rock lies above and was deposited on the pre-existing and eroded metamorphic or igneous rock.


h) Structure: A geological feature produced by deformation of the Earth's crust, such as a fold or a fault; a feature within a rock, such as a fracture or bedding surface; or, more generally, the spatial arrangement of rocks.

i) Growth fault: • A fault in sedimentary rock that forms contemporaneously and continuously with

deposition, so that the throw increases with depth and the strata of the down-thrown side are thicker than the correlative strata of the up-thrown side.

• A type of normal fault that develops and continues to move during sedimentation and typically has thicker strata on the downthrown, hanging wall side of the fault than in the footwall. Growth faults are common in the Gulf of Suez and in other areas where the crust is subsiding rapidly or being pulled apart.

j) Structure depth map: A type of subsurface map whose contours represent the elevation of a particular formation, reservoir or geologic marker in space, such that folds, faults and other geologic structures are clearly displayed. Its appearance is similar to that of a topographic map, but a topographic map displays elevations of the Earth's surface and a structure map displays the elevation of a particular rock layer, generally beneath the surface.

k) Clysmic fault: …………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………..


l) Mud circulation:

m) Mud log unit: The system integrates powerful computer network technique, highly accurate and reliable sensor technique, analysis and evaluation technique of rock samples such as geochemical, nuclear magnetic resonance and quantitative fluorescence, and it is the center of quick and comprehensive interpretation and evaluation of oil and gas on well-site. The system can discover and evaluate oil and gas reservoirs quickly, monitor drilling engineering parameters and toxic gases such as H2S and CO2, thus to ensure drilling safety, enhance drilling efficiency and reduce operation cost. The mud logging unit has served in domestic oilfields.

n) Lag time: • It is the time between a chip being cut by the bit and the time it reaches to the surface

where it is then examined by the wellsite geologist or mudlogger. • The time taken for cuttings sample to reach the surface. The term is also used in place of

cycle time.


o) Attic oil: ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

p) Migration: • In Geology: The movement of hydrocarbons from their source into reservoir rocks. The

movement of newly generated hydrocarbons out of their source rock is primary migration, also called expulsion. The further movement of the hydrocarbons into reservoir rock in a hydrocarbon trap or other area of accumulation is secondary migration. Migration typically occurs from a structurally low area to a higher area because of the relative buoyancy of hydrocarbons in comparison to the surrounding rock. Migration can be local or can occur along distances of hundreds of kilometers in large sedimentary basins, and is critical to the formation of a viable petroleum system.

• In Geophysical: A step in seismic processing in which reflections in seismic data are moved to their correct locations in the x-y-time space of seismic data, including two-way traveltime and position relative to shotpoints. Migration improves seismic interpretation and mapping because the locations of geological structures, especially faults, are more accurate in migrated seismic data. Proper migration collapses diffractions from secondary sources such as reflector terminations against faults and corrects bow ties to form synclines. There are numerous methods of migration, such as dip moveout (DMO), frequency domain, ray-trace and wave-equation migration.

q) Muting: • To remove the contribution of selected seismic traces in a stack to minimize air waves,

ground roll and other early-arriving noise. Low-frequency traces and long-offset traces are typical targets for muting.

• Remove arrivals that are not primary reflections or make it zero. r) Stacking: • The stacking velocity is used to correct the arrival times of events in the traces for their

varying offsets prior to summing, or stacking, the traces to improve the signal-to-noise ratio of the data.


s) Common mid-point (CMP): • Having the same midpoint between source

and detector, the location to which the reflections are migrated (or gathered) during seismic processing.

• The point on the surface halfway between the source and receiver that is shared by numerous source-receiver pairs. The common midpoint is vertically above the common depth point, or common reflection point. Common midpoint is not the same as common depth point, but the terms are often incorrectly used as synonyms.

t) Common depth point (CDP): • More correctly CMP where beds do not dip,

the common reflection point at depth on a reflector, or the halfway point when a wave travels from a source to a reflector to a receiver. In the case of flat layers, the common depth point is vertically below the common midpoint. In the case of dipping beds, there is no common depth point shared by multiple sources and receivers, so dip moveout processing is necessary to reduce smearing, or inappropriate mixing, of the data.

• point is the halfway point in the travel of a wave from a source to a flat-lying reflector to a receiver.

u) Pull up: A phenomenon of relative seismic velocities of strata whereby a shallow layer or feature with a high seismic velocity (e.g., a salt layer or salt dome, or a carbonate reef) surrounded by rock with a lower seismic velocity causes what appears to be a structural high beneath it. After such features are correctly converted from time to depth, the apparent structural high is generally reduced in magnitude.


Normal moveout (NMO):

• The traces from different source-receiver pairs that share a midpoint can be corrected during seismic processing to remove the effects of different source-receiver offsets.

• The effect of the separation between receiver and source on the arrival time of a reflection that does not dip, abbreviated NMO. A reflection typically arrives first at the receiver nearest the source. The offset between the source and other receivers induces a delay in the arrival time of a reflection from a horizontal surface at depth. A plot of arrival times versus offset has a hyperbolic shape.

• A function of time and offset that can be used in seismic processing to compensate for the effects of normal moveout, or the delay in reflection arrival times when geophones and shotpoints are offset from each other.

v) Ghost multiple: A short-path multiple, or a spurious reflection that occurs when seismic energy initially reverberates upward from the shallow subsurface and then is reflected downward, such as at the base of weathering or between sources and receivers and the sea surface.


w) Interval velocity: The velocity, typically P-wave velocity, of a specific layer or layers of rock, symbolized by vint and commonly calculated from acoustic logs or from the change in stacking velocity between seismic events on a common midpoint gather.

x) Reflection coefficient: The ratio of amplitude of the reflected wave to the incident wave, or how much energy is reflected. If the wave has normal incidence, then its reflection coefficient can be expressed as:

Typical values of R are approximately -1 from water to air, meaning that nearly 100% of the energy is reflected and none is transmitted; ~ 0.5 from water to rock; and ~ 0.2 for shale to sand. At non-normal incidence, the reflection coefficient defined as a ratio of amplitudes depends on other parameters, such as the shear velocities, and is described as a function of incident angle by the Zoeppritz equations.

y) Snell's Law The mathematical description of refraction, or the physical change in the direction of a wavefront as it travels from one medium to another with a change in velocity and partial conversion and reflection of a P-wave to an S-wave at the interface of the two media. Snell's law, one of two laws describing refraction, was formulated in the context of light waves, but is applicable to seismic waves. It is named for Willebrord Snel (1580 to 1626), a Dutch mathematician. Snell's law can be written as:


4- What is the difference between:

a) Reverse and Thrust Fault Reverse Fault Thrust Fault

Reverse > 45◦ Thrust < 45◦ Compression Force Compression Force

b) Porosity and Effective Porosity Porosity Effective Porosity

It is the percentage of pore volume or void space to the total volume of rock. It is the ability of the rock to hold the fluid.

The interconnected pore volume or void space in a rock that contributes to fluid flow or permeability in a reservoir.

The percentage of pore volume or void space, or that volume within rock that can contain fluids. Porosity can be a relic of deposition (primary porosity, such as space between grains that were not compacted together completely) or can develop through alteration of the rock (secondary porosity, such as when feldspar grains or fossils are preferentially dissolved from sandstones). Porosity can be generated by the development of fractures, in which case it is called fracture porosity.

The interconnected pore volume or void space in a rock that contributes to fluid flow or permeability in a reservoir. Effective porosity excludes isolated pores and pore volume occupied by water adsorbed on clay minerals or other grains. Total porosity is the total void space in the rock whether or not it contributes to fluid flow. Effective porosity is typically less than total porosity. Shale gas reservoirs tend to have relatively high porosity, but the alignment of platy grains such as clays makes their permeability very low.

c) Dolomite, Anhydrite and Limestone Dolomite Anhydrite Limestone

CaMg(CO3)2 CaCO3 CaSO4 Hcl test with dolomite is slow reaction.

Anhydrites not react with Hcl test.

Hcl test with Limestone is Strong and rapid reaction.

There are two type of dolomite primary and secondary Dolomite where Second dolomite is good Reservoir rock.

May occur as a cap rock above salt domes.

Reservoir rock.

Color: Beige. Color: Snow Whigh.


d) Fault and joint Fault joint

Found in large scale Found in small scale There are displacements parallel to the defining plane of rock. There is no displacement

parallel to the defining plane of rock.

A break or planar surface in brittle rock across which there is observable displacement. Depending on the relative direction of displacement between the rocks, or fault blocks, on either side of the fault, its movement is described as normal, reverse or strike-slip. According to terminology derived from the mining industry, the fault block above the fault surface is called the hanging wall, while the fault block below the fault is the footwall. Given the geological complexity of some faulted rocks and rocks that have undergone more than one episode of deformation, it can be difficult to distinguish between the various types of faults. Also, areas deformed more than once or that have undergone continual deformation might have fault surfaces that are rotated from their original orientations, so interpretation is not straightforward. In a normal fault, the hanging wall moves down relative to the footwall along the dip of the fault surface, which is steep, from 45o to 90o. A growth fault is a type of normal fault that forms during sedimentation and typically has thicker strata on the downthrown hanging wall than the footwall. A reverse fault forms when the hanging wall moves up relative to the footwall parallel to the dip of the fault surface. A thrust fault, sometimes called an overthrust, is a reverse fault in which the fault plane has a shallow dip, typically much less than 45o. Movement of normal and reverse faults can also be oblique as opposed to purely parallel to the dip direction of the fault plane. The motion along a strike-slip fault, also known as a transcurrent or wrench fault, is parallel to the strike of the fault surface, and the fault blocks move sideways past each other. The fault surfaces of strike-slip faults are usually nearly vertical. A strike-slip fault in which the block across the fault moves to the right is described as a dextral strike-slip fault. If it moves left, the relative motion is described as sinistral. A transform fault is a particular type of strike-slip fault that is a boundary of an oceanic tectonic plate. The actual movement of a transform fault is opposite to its apparent displacement. The presence of a fault can be detected by observing characteristics of rocks such as changes in lithology from one fault block to the next, breaks and offsets between strata or seismic events, and changes in formation pressure in wells that penetrate both sides of a fault. Some fault surfaces contain relatively coarse rubble that can act as a conduit for migrating oil or gas, whereas the surfaces of other faults are smeared with impermeable clays or broken grains that can act as a fault seal.

A surface of breakage, cracking or separation within a rock along which there has been no movement parallel to the defining plane. The usage by some authors can be more specific: When walls of a fracture have moved only normal to each other, the fracture is called a joint.


e) Erosion and digenesis Erosion digenesis

The process of denudation of rocks, including physical, chemical and biological breakdown and transportation.

In Rock: The physical, chemical or biological alteration of sediments into sedimentary rock at relatively low temperatures and pressures that can result in changes to the rock's original mineralogy and texture. After deposition, sediments are compacted as they are buried beneath successive layers of sediment and cemented by minerals that precipitate from solution. Grains of sediment, rock fragments and fossils can be replaced by other minerals during diagenesis. Porosity usually decreases during diagenesis, except in rare cases such as dissolution of minerals and dolomitization. Diagenesis does not include weathering processes. Hydrocarbon generation begins during diagenesis. There is not a clear, accepted distinction between diagenesis and metamorphism, although metamorphism occurs at pressures and temperatures higher than those of the outer crust, where diagenesis occurs.

The process by which material weathered from rocks is transported by wind, water, ice, or abrasive solid particles, or by mass-wasting, as in rock falls and landslides.

In Petroleum: The initial stage of alteration of sediments and maturation of kerogen that occurs at temperatures less than 50°C [122°F]. The type of hydrocarbon generated depends on the type of organic matter in the kerogen, the amount of time that passes, and the ambient temperature and pressure. During early diagenesis, microbial activity is a key contributor to the breakdown of organic matter and generally results in production of biogenic gas. Longer exposure to higher temperatures during diagenesis, catagenesis, and metagenesis generally results in transformation of the kerogen into liquid hydrocarbons and hydrocarbon gases.

There is no change in chemical composition.

There is change in chemical composition.

f) Continental and marine Continental Marine

There are many type of continental environmental deposits: a) Terrestrial deposits:

1. Desert deposits 2. Glacial deposits

b) Fluvial deposits 1. Alluvial Fan 2. River & Stream 3. Piedmonts sediment 4. Valley flat sediment

c) Lake deposits(Lacoustrine) d) Cave deposits(Spelal)

There are many type of marine environmental deposits: a) Marine shoreline environment. b) Shallow Marine (Neritic Zone). c) Intermediate Seas (Bathyal Deposits) d) Deep Marine (Abyssal Deposits)

Main site of reservoir rocks not found in continental environment.

Main site of reservoir rocks found in continental environment.


g) Shale and sandstone. Shale Sandstone

Source Rock or Cap Rock Reservoir Rock Good porosity and very low permeability. Good porosity and Good permeability.

h) Quartz, Calcite, Orthoclase and Gypsum Quartz Calcite Orthoclase Gypsum

It is hardness is 7 It is hardness is 3 It is hardness is 6 It is hardness is 2


5- Choose the correct answer:

1.Um Baraka Field is in a) Nile Delta. b) Western Desert. c) Gulf of Suez. d) Sinai.

2.Known oil seeps exist in a) AbuMadi. b) Alamein. c) Gemsa. d) Abu Rudeis.

3.What is the daily oil production of Egypt? a) About 100,000 bbls/day b) About 250,000 bbls/day c) About 550,000 bbls/day d) About 1000,000 bbls/day

4.What is the current approximate price of one barrel oil? a) US $99. b) US $50. c) About US $110. d) US $150.

5.Shoaab Ali oil Field present: in a) Western Desert. b) Nile Delta. c) Gulf of Suez.

6.Most of the gold mines in Egypt exist in a) Western Desert. b) Eastern Desert. c) Sinai.

7.Which Oasis has iron ore? a) El Kharga Oasis. b) El Bahariya Oasis. c) Siwa Oasis. d) Farafra Oasis.


8.Where is the known phosphate mining in Egypt? a) Edfo. b) Ras El Dip. c) Abu Tartoor. d) Badracheen.

9.Where is the oil shale Present in Egypt? a) Ras Shukeir. b) Gebel El Zeit. c) Abu Tartoor Plateau. d) Alexandria. • The kerogen type ranges from Type I for Safaga oil shales to Type II for

both of Hamrawein and Ouseir districts and although found in Abu Tartur area.

10. Nearly the whole land surface of earth was covered by huge sheet of ice during a) Cambrian. b) Precambrian. c) Cretaceous. d) Pleistocene. e) Jurassic.

11. The Dead Sea is located in a) Rift valley. b) Canyon. c) Between chains of mountains. d) Intermountain plain.

12. The age of economic coal bearing rocks in Egypt is a) Cretaceous. b) Carboniferous. c) Triassic. d) Jurassic.

13. First vertebrates (Fishes) appeared in a) Paleocene. b) Devonian. c) Ordovician. d) Cambrian.


14. Outcrop of strata shown in geological map as parallel contour indicates a) Horizontal Strata. b) Vertical Strata. c) Inclined Strata. d) Strata inclined 45°.

15. On a map, which of the following scales is considered the largest a) 1:100,000. b) 1:50,000. c) 1:10,000. d) 1:200,000. • Large scale maps or small scale maps

- A large scale map shows greater detail because the scale is a larger fraction than a small scale map.

- Large scale maps have a scale of 1:50,000 or greater (1:24,000, 1:10,000, ...). - Maps with scales from 1:50,000 to 1:250,000 are considered intermediate. - Small scale maps are those with scales smaller than 1:250,000.

16. The Tethys sea evaporated completely during a) Eocene. b) Middle Miocene. c) Pliocene. d) Oligocene.

17. In which period the Red Sea was opened? a) Eocene. b) Tertiary. c) Mesozoic. d) Proterozoic.

18. Time rock units are defined as a) Lithologic characteristics. b) Lithologic characteristics and time boundaries. c) Lithologic characteristics and fossil content. d) Lithologic characteristics and index fossils.

19. Syrian arc structures in Egypt date back to a) Paleozoic time. b) Miocene time. c) Cretaceous. d) Jurassic time.


20. Strike slip movement shows a) Right Lateral. b) Left Lateral. c) Clock wise. d) Anti-clock wise.

21. Cross beds are produced when a) The Flow direction of current changes gradually. b) The Flow direction of current changes suddenly. c) Velocity of current decrease suddenly. d) Ripples migrate from one place to another.

22. Arrange the following environmental zones sea-ward a) Bathyal.(3) b) Neritic. (2) c) Abyssal.(4) d) Littoral.(1)

23. What type of log do we use for porosity calculation? a) Density / Neutron. b) Resistivity. c) Gamma Ray.

24. What type of log do we use for Lithology identification? a) Microspherical. b) Density. c) Caliper.


25. How can we differentiate between heavy and light oil response on resistivity curves? a) Deep and Shallow readings are the same. b) Separation between Deep and Shallow readings in good permeable reservoirs. c) We can't differentiate.

26. Caliper log helps to determine a) Oil zones. b) Hole size. c) Hole inclination.

27. Dipmeter tool measures a) Oil bearing reservoirs. b) Bed dips. c) TWT.

28. We measure shaliness (VSH) from a) VSP. b) Sonic. c) GR.

29. Resistivity is inversely proportional to a) Tightness. b) Oil presence. c) Formation water salinity.

30. Petrophysical Computation is performed on a) Any data. b) Raw data. c) Data after Environmental Correction

31. Which of the following is not a stratigraphic oil trap? a) Unconformity. b) Reef. c) Anticline. d) Pinchout.

32. Index fossils are most useful when they cover a large geological age while exist in a limited geographical area so that they identify (or date) the rock formation in which they are found. a) True. b) False.


33. The CaSO4 is known in nature as: a) Limestone b) Anhydrite. c) Gypsum. d) None of the above.

34. Fissility is a rock sample description specific for: a) Limestone. b) Shale. c) Sandstone. d) Salt.

35. Which of the following is not a hydrocarbon: a) Methane. b) Pentane. c) Acetylene. d) None of the above. e) All of the above.

36. The definition: "the pore spaces – connected or disconnected – resulting through alteration of a rock, commonly by processes such as dolimitization, dissolution or fracturing" belongs to: a) Primary porosity. b) Permeability. c) Secondary porosity. d) Effective porosity.

37. According to moh's scale of rock hardness, which of the following minerals is the softest: a) Orthoclase. b) Gypsum. c) Quartz. d) Fluorite. • moh's scale: Talc(1) - Gypsum(2) - Calcite(3) - Fluorite(4) - Apatite(5) -

Orthoclase(6) - Quartz(7) - Topaz(8) - Corundum(9) - Diamond(10).

38. Which of the following describes a rock with clay content: a) Calcareous. b) Fossiliferous. c) Arenaceous. d) Argillaceous.


39. Which of the following is not a fault type: a) Strike- slip. b) Oblique – slip. c) Anti- dip. d) Dip- slip.

40. Give an example of a rock with high porosity and high permeability.(Sand Stone)

41. Give an example of a rock with high porosity and low permeability. (Shale)

42. Give an example of a rock with low porosity and low permeability. (Salt)

43. Which of the following is not an evaporite rock: a) Gypsum. b) Evaporite. c) Muscovite. d) Salt.

44. Arrange the following ages chronologically (mark them1 to 5 where 1 is the oldest): a) Tertiary. ( 4 ) b) Cambrian. ( 1 ) c) Triassic. ( 2 ) d) Jurassic. ( 3 ) e) Quaternary. ( 5 )

45. Porosity of shales for a geologic environment which is characterized by continuous, uninterrupted deposition and normal pore pressure: a) Increases linearly with increasing depth. b) Decreases linearly with increasing depth. c) Decreases basically exponentially with increasing depth. d) Exhibits an inversely proportional behavior to density. e) A and D above. f) C and D above.


46. The diagenesis of montmorillonite to illite and mixed-layer clays: a) Requires only particular conditions of temperature. b) Occurs only at depths normally exceeding 5000 ft. c) Occurs only after most free pore water has been expelled. d) Requires particular conditions of temperature and (somewhat) pressure and

the availability of potassium ions. e) May occur at relatively shallow depths. f) B, C and D above. g) D and E above.

47. During compaction, particularly shales, free pore water is expelled: a) Towards the depositional surface. b) In any direction including downwards. c) In a linear fasion. d) In several stages. e) A and D. f) B and C.


6- (√) or (x) And Correct the following statements:

- Urn Bogma formation is related to Cretaceous Age. (x) To Carboniferous Age.

- Jurrasic sediments are well exposed in G. Maghara. (√)

- The plant remains are called Trace Fossils. (x) Called Fossil.

- Zeit formation is related to the Pliocene Age. (x) To the Late Miocene Age.

- The Genus may contain many orders. (x) Contain many Species. • Kingdom→ Phyla →Class →Order →Family →Genus →Species.

- Belayim formation is younger than Abu Roash formation. (√)

- Kareem formation is well developed in Abu Gharadig field. (x) In Ras Budran

- Abu Madi formation is well developed in Gulf of Suez. (x) In Nile Delta

- Sudr formation is very thick body of fine Sandstone in Gulf of Suez. (x) Chalk

- True Dip is always smaller than apparent dip (x) May be Larger

- True thickness is always smaller than apparent thickness (√)

- If a normal fault is existing in a folded structure, the fault strike will be parallel to the fold axis (x)

- A normal fault is a result of tensile stress (√)

- Folds are a result of compressive stress (√)

- Shale is acting as a good seal as well as a good source rocks for Hydrocarbon (√)

- Source rocks are deposited under reducing environment (√)

- Density of oil is higher than density of water (x) Smaller

- The porosity decreases with depth (√)

- Basement rocks of primary porosity could act as good reservoir (x) Bad Reservoir


- Hydrocarbon could be trapped on both side of the fault (√)

- Sound speed in water (√) • The speed of sound is determined by the density (ρ) and compressibility (K) of

the medium. The speed of sound is about four times faster in water than in air.

- Sonic tool is used to determine the primary porosity (√) • The Sonic tool tends to ignore the effect of fractures or vugs, which result in

secondary porosity. The Sonic tool therefore measures primary porosity only which is less than true total porosity if fractures or vugs exist.

- Shale is highly porous and permeable rock (x). and low permeable rock

- The arkoses sandstones is highly feldspar content (√) 25% or more feldspar grains

- Ooids or oolith is allochems with clear internal structure (√)


7- Write the Chemical composition of:

Limestone: CaCO3 Chalk: CaCO3

Around 80-90% of limestone grains are skeletal fragments of marine organisms such as coral or foraminifera. Other carbonate grains comprising limestones are ooids, peloids, intraclasts, and extraclasts. Some limestones do not consist of grains at grains at all and are formed completely by the chemical precipitation of calcite or aragonite. I.e. Travertine.

Marl: CaCO3 Calcium carbonate or lime-rich mud

Dolomite: CaMg(CO3)2 There are two main types of Dolomite: Primary Dolomite: Deposited directly from marine water that rich in Mg and Ca and CO3. Secondary Dolomite: formed from by metaformic process (Dolomitization) of Limestone.

Anhydrite: CaSO4 From aqueous solution calcium sulfate is deposited as crystals of gypsum, but when the solution contains an excess of sodium or potassium chloride anhydrite is deposited if temperature is above 40°C

Gypsum: CaSO4·2H2O Usually from precipitation out of highly saline waters

Halite: NaCl It commonly occurs with other evaporite deposit minerals such as several of the sulfates, halides, and borates.

Siderite: FeCO3 It is 48% iron and contains no sulfur or phosphorus. Both magnesium and manganese commonly substitute for the iron

Hematite: Fe2O3 It is the mineral form of iron (III) oxide, colored black to steel or silver‐gray, brown to reddish brown, or red.

Magnetite: Fe3O4 It is a ferrimagnetic mineral

Goethite: FeO (OH) Is an iron bearing oxide mineral found in soil and other low-temperature environments, often forms through the weathering of other iron-rich minerals

Limonite: FeO(OH)·4H2O It is never crystallized into macroscopic crystals, but may have a fibrous or microcrystalline structure, and commonly occurs in concretionary forms

Chamosite: Fe3Al2Si2O10.3H2O

Greenlite: Fe2SiO3.4H2O

Glauconite: (K,Na,Ca)1.2-2.0(Fe+3,Al,Fe+2,Mg)4(Si7-7.6Al1-0.4O20)(OH)4·7H2

Pyrite: FeS2 Marcasite: FeS2


8- Draw with mentioning type of the force of:

Thrust fault: compaction force

Reverse Fault: compaction force

Grabben: Tension force (from Normal Faults)

Horest: Tension force (from Normal Faults)

9- What is the major structure which separate between Tertiary and Pre-tertiary in Nile Delta?

Syrian Arc system that formed in Cretaceous Age that have trend from NE to SW direction.


10- What is the major type of traps in GOS? Structure traps (Normal Fault, horst and grabben) that formed fom tension force that formed Gulf of Suez.

11- Calculate in steps the scale of your map? Calculating the Map Scale:

Maps are considered

Large scale maps or small scale maps A large scale map shows greater detail because the scale is a larger fraction than a small scale map. Large scale maps have a scale of 1:50,000 or greater (1:24,000, 1:10,000, ...). Maps with scales from 1:50,000 to 1:250,000 are considered intermediate. Small scale maps are those with scales smaller than 1:250,000. A map of the world that fits on two pages of letter sized paper would be very small scale with a scale of around 1:100,00,000. Here are 3 views of the same location on maps with different scales:

12- What is the angle of strike-slip fault? Zero or nearly so, where is small degree of dip for strike slip fault because it's move in lateral direction. A type of fault whose surface is typically vertical or nearly so. The motion along a strike-slip fault is parallel to the strike of the fault surface, and the fault blocks move sideways past each other. A strike-slip fault in which the block across the fault moves to the right is described as adextral strike-slip fault. If it moves left, the relative motion is described as sinistral. Local deformation near bends in strike-slip faults can produce pull-apart basins and grabens. Flower structures are another by-product of strike-slip faults. A wrench fault is a type of strike-slip fault in which the fault surface is nearly vertical.


13- What are types of faults? There are many types of fault Genetic classification: Normal fault Reverse Fault Thrust fault Strike sleep fault Oblique fault Step Fault Horist Fault Grabben Fault Ground Roll fault Ground Roll fault Listric Fault Dip sleep fault

14- What do you know about miscellaneous reservoirs and what is the most famous example in Gulf of Suez? It is reservoir formed from fragment igneous rocks that found mainly in GOS province in SUCO Company in Zeit Bay Field

15- mention 5 fields in GOS and mention the horizon of production Field Formation

Sabil Zaafarana Fm. Belayim Land Belayim Fm. Morgan Kareem Fm. Ras Fanar Belayim Nullipore. October Nukhul Fm. Bakr Kareem Thebes Fm. Belayim Marine Wata Fm. Ramadan Malha Fm. (Nubia A) Shoab Ali Abu Thura Fm. (Nubia B, C) Ras Gharib Hurghada (Sidki Hilal) Naqus Fm. (Nubia D) Zeit Bay, Ashrafi, Geisum Basement Precambrian

16- According to stratigraphic sequence what is the reservoir geometry in the down dip? Located down the slope of a dipping plane or surface. In a dipping (not flat-lying) hydrocarbon reservoir that contains gas, oil and water, the gas is updip, the gas-oil contact is downdip from the gas, and the oil-water contact is still farther downdip. Downdip. Well 2 is downdip of both Well 1 and the oil-water contact. Well 1 is updip of the oil-water contact.


a. 21ة بت What are the favorable conditions to form oil (environmental of petroleum formation)?

- Petroleum is formed in all sediments either continental or marine. - Petroleum is found in all rock from pre-Cambrian to Pleistocene. - Aqueous environment is best for accumulation of organic matter and their

transformation to petroleum. - Petroleum originates in reducing and anaerobic environment. - Petroleum is composed of homogenous series of hydrocarbons but no two

petroleum are alike. - Reservoir tempreture (107◦ C to 141◦ C deep reservoir) - Reservoir pressure from atmospheric pressure to 10.000 psi. - Minimum time for petroleum formation is one million year.

17- What is the condition for commercial petroleum There are five conditions for commercial petroleum:

- Organic matter (Source Rock) - High temperature and pressure for transformation of organic material to petroleum. - Reservoir rock with high porosity and permeability and lateral extension. - Seal rock (cap rock) Ex. Anhydrite, shale or salt. - Trap in all types (Structure, Stratigraphy and Combination).

18- What is the types of migration a) Primary migration: from source rock to reservoir rock. b) Secondary migration: from reservoir rock to trap. c) Subsequence migration: from trap to another trap. - where causative force of oil migration is

1. Pressure (Compaction, hydraulic pressure). 2. Buoyancy (Floating, gravity). 3. Capillary Pressure. 4. Gas Expantion.

- where Direction of Migration may be 1. Transverse

• When oil direction perpendicular to the direction of pressure. • Fault fracture (when there is a fault and the buoyancy to up).

2. Parallel • Variation of facies. Or in multi folding layer

- Where oil migrated one foot/year or 190 miles/million year.


19- What are the reasons of presence of barren Trap?

1. No source material. 2. No generation of oil:

• Absence of necessary catalysis. • The time of transformed is not enough. • Oxidation medium. • Intense diastrophism.

3. Oil failed to reach traps. 4. Oil has escaped. 5. Oil destroyed by:

• Relatively intense diastrophism. • Weathering. • The activity of hydrocarbon consuming bacteria.

6. Trap has formed too late.

20- How do we measure the Mud cake thickness?

By use Caliper log

21- Write Archie's Equation for saturation? A particular relation proposed by G.E. Archie between the formation factor (F) and porosity (phi), in which F = 1 / phim, where the porosity exponent, m, is a constant for a particular formation or type of rock. In the original work, Archie proposed that m lay between 1.8 and 2.0 for consolidated sandstones and close to 1.3 for loosely consolidated sandstones. m was named the cementation exponent shortly afterwards. This relation is also known as the Archie II equation.

• Sw = [ (a / Fm)*(Rw / Rt) ](1/n) • Sw: water saturation • F: porosity • Rw: formation water resistivity • Rt: observed bulk resistivity • a: a constant (often taken to be 1) • m: cementation factor (varies around 2) • n: saturation exponent (generally 2)


22- How many geophysical methods are there? (Name them) Method Measured parameter “Operative” physical

property Gravity

Spatial variations in the strength of the gravitational field of the Earth

density

Magnetic

Spatial variations in the strength of the geomagnetic field

Magnetic susceptibility and remanence

Electromagnetic (Seabed Logging)

Response to electromagnetic radiation Electric conductivity/resistivity and inductance

Seismic

Travel times of reflected/refracted seismic waves

Seismic velocity (and density)

23- Indicate whether the following increase (I), decrease (D) or remain the same (S) with increasing depth in normally compacted shales:

a) Porosity. (D) b) Density. (I) c) Seismic velocity. (I) d) Sonic transit time. (Interval velocity) (D) e) Electrical resistivity. (D) f) Matrix stress gradient. (I) g) Compressive strength. (I)

24- When SP can’t measure? Rmf/Rw (Salinity effect) Fresh mud: negative SP, Saline mud: positive SP. Shale or clay content: Shale reduces SP. Permeability. Presence of hydrocarbon. Bed thickness: SP decreases when bed thickness decreases. Invasion: Reduces SP. Mud filtrate: The magnitude and direction of SP deflection from the shale baseline depends on relative resistivities of the mud filtrate and the formation water. Resistive formations.


25- What do you know about SP & GR tools?

• Spontaneous Potential: This tool measures the potential difference naturally occurring when mud filtrate of certain salinity invades the formation containing water of a different salinity. It may be used to estimate the extent of invasion and in some cases the formation water salinity. A log of the natural difference in electrical potential, in millivolts, between an electrode in the borehole and a fixed reference electrode on the surface. The most useful component of this difference is the electrochemical potential since it can cause a significant deflection opposite permeable beds. The magnitude of the deflection depends mainly on the salinity contrast between drilling mud and formation%20water">formation water, and the clay content of the permeable bed. The spontaneous potential (SP) log is therefore used to detect permeable beds and to estimate formation water salinity and formation clay content. The SP log cannot be recorded in nonconductive mud. The SP can be affected by several factors that make interpretation difficult. First, there are other possible sources of electrical potential not related to the electrochemical effect, for example, the electrokinetic potential and bimetallism. Many of these are small and constant throughout the log, and can be lumped together in the shale baseline. Second, the SP can measure only the potential drop in the borehole, and not the full electrochemical potential. The ideal SP opposite a clean bed is known as the static spontaneous potential (SSP), and opposite a shaly bed as the pseudostatic spontaneous potential (PSP). The SP is always less than the SSP or the PSP and more rounded at the boundaries between shales and permeable beds.

• Gamma Ray Log: A log of the total natural radioactivity, measured in API units. The measurement can be made in both open hole and through casing. The depth of investigation is a few inches, so that the log normally measures the flushed zone. Shales and clays are responsible for most natural radioactivity, so the gamma ray log often is a good indicator of such rocks. However, other rocks are also radioactive, notably some carbonates and feldspar-rich rocks. The log is also used for correlation between wells, for depth correlation between open and cased hole, and for depth correlation between logging runs.


26- How can you calculate? a) interval velocity

The velocity, typically P-wave velocity, of a specific layer or layers of rock, symbolized by vint and commonly calculated from acoustic logs or from the change in stacking velocity between seismic events on a common midpoint gather.

b) reflection coefficient

The ratio of amplitude of the reflected wave to the incident wave, or how much energy is reflected. If the wave has normal incidence, then its reflection coefficient can be expressed

as:

27- Talk about yourself and what did you do from the morning after the exam till now

61362665 All Exams in One

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