CHAPTER 1 MODULE VERSION

Question 1

is the study of rock properties and their interactions with fluids (gases,
liquid hydrocarbons, and aqueous solutions).

Answer 1

Petrophysics

Question 2

are composed of
fragments of other roeks derived from mechanical and chemical deterioration of igneous,
metamorphic, and other sedimentary rocks, which is constantly occurring

Answer 2

Sedimentary Rocks

Question 4

describes the complex interaction between physically
distinct, separable portion of matter called phases that are in contact with each other,

Answer 4

Hydrocarbon phase behavior

Question 5

physically
distinct, separable portion of matter is called _____

Answer 5

Phases

Question 6

Typical phases are _______. _______ plays a vital role in many
petroleum applications, such as enhanced oil recovery, compositional simulation,
geochemical behavior, wellbore stability’, geothermal energy, environmental cleaning,
multiphase flow in wellbores and pipes, and surface facilities.

Answer 6

solids, liquids, and vapor.

Phase bchavior

Question 7

the study of
energy and its transformations. Also central to understanding phase behaviors

Answer 7

Thermodynamics

Question 8

quantity of
hydrocarbons present in each volume of these rocks depends largely on two factors:

Answer 8

Porosity
Hydrocarbon Saturation

Question 9

indicates the storage capacity of the rock, answering the question “how
much space is available in the rock?

Answer 9

Porosity

Question 10

denotes the
proportion of the pore spaces ocupied by hydrocarbons, answers hich volune fraction
of the pore space is occupied by oil, gas, and water?

Answer 10

Hydrocarbon Saturation

Question 11

Thickness and area, which directly affect the volume of hydrocarbons that can be recovered.

Answer 11

spatial extent of the reservoir

Question 12

the ease with which these fluids can migrate through the
reservoir rock,

Answer 12

Permeability

Question 13

“At what rate can I produce a
fluid?”

Answer 13

Permeability

Question 14

is a crucial factor in assessing the reservoir’s productivity/producibility

Answer 14

Permeability

Question 15

Identifies the composition of oil, gas, and water present in the reservoir

Answer 15

Fluid Type

Question 16

Two Techniques Use for Determination of Reservoir Properties

Answer 16

Direct
Indirect

Question 17

Two primary techniques are used for this purpose: direct
measurements on ________ and indirect derivation from __________.

Answer 17

Core samples
Well Logs and Formation Analysis

Question 18

involve extracting core samples from the subsurface reservoir
during drilling and analyzing them in specialized core laboratories.

Answer 18

Direct Measurements

Question 19

Samples from direct measurements provide what information?

Answer 19

Point-information

Question 20

representing the properties of the reservoir at specific depths and
locations

Answer 20

Point-formation

Question 21

involves a range of laboratory techniques to determine properties
such as porosity, permeability, grain density, and fluid saturation

Answer 21

Core Analysis

Question 22

provides highly accurate and detailed information on the reservoir’s
properties

Answer 22

Core Analysis

Question 23

Core analysis provides highly accurate and detailed information on the reservoir’s
properties. However, the limitation of this approach is that it only provides data for a
limited volume of the reservoir, resulting in a _______ dataset. Since it represents specific
“____” within the reservoir, it might not capture the full variability of the formation.
especially in ___________ reservoirs. Despite this limitation, core data are invaluable as
they offer a direct and physical basis for understanding reservoir characteristics, serving as
a reference for _______ indirect measurements.

Answer 23

discrete
Points
heterogeneous
calibrating

Question 24

involve using well logs, which are continuous recordings of
physical properties made while drilling or affer the well has been completed.

Answer 24

Indirect techniques

Question 25

continuous recordings of physical properties made while drilling or affer the well has been completed.

Answer 25

Well logs

Question 26

These measurements provide continuous data along the wellbore, offering a detailed vertical profile of the formation

Answer 26

Indirect Techniques

Question 29

plays a crucial role in reservoir characterization, offering valuable data that supports and validates 1og analysis.

Answer 29

Core Analysis

Question 30

Due to the additional rig time required for coring, it is an expensive process, often limited to the reservoir interval to minimize costs.

Answer 30

Core Analysis

Question 31

There are two primary methods for acquiring cores:

Answer 31

Conventional or Rotary Sidewall

Question 32

These are full-diameter cores that range from 1 %4 inches (4.5 cm) to 5%4 inches (13.5 cm) in diameter.

Answer 32

Conventional or Rotary Cores

Question 33

These cylindrical samples provide a continuous and detailed record of the rock formations, allowing for in-depth analysis of the reservoir properties.

Answer 33

Conventional

Question 34

During coring, the loss of core material can be an indicator of a ____ reservoir rock, as it often suggests the presence of ______ porosity or permeability

Answer 34

good high

Question 37

These samples are smaller and may not provide comprehensive information, but they are useful for acquiring data when budget constraints or operational limitations prevent full-diameter coring.

Answer 37

Swc

Question 39

Core Analysis 2 categories

Answer 39

Rcal Scal

Question 40

focuses on the fundamental reservoir properties such as porosity, permeability, and fluid saturation. This information is essential for validating I0g interpretations and providing a baseline for reservoir characterization.

Answer 40

Routine Core Analysis (RCAL)

Question 41

goes beyond routine measurements to determine more complex petrophysical properties, such as capillary pressure, relative permeability, wettability, and Archie's parameters (m and n). These advanced analyses help in understanding fluid flow dynamics and reservoir behavior under various production scenarios

Answer 41

Special Core Analysis (SCAL)

Question 42

Core Analysis Categories ________ This information is essential for validating Iog interpretations and providing a baseline for reservoir characterization. ___________These analyses help in understanding fluid flow dynamics and reservoir behavior under various production scenarios

Answer 42

RCAL SCAL

Question 43

Reservoir rocks classification

Answer 43

Clastic Carbonate

Question 44

Clastic (_______) Carbonate(_____ and _____)

Answer 44

Sandstone Limestone and Dolomite

Question 45

are formed from the compaction and cementation of mineral grains, primarily quartz, feldspar, and rock fragments. These grains are transported by wind, water, or ice and deposited in various environments such as rivers, beaches, and deserts.

Answer 45

Clastic Rocks

Question 46

are among the most prevalent reservoir rocks due to their favorable porosity and permeability characteristics.

Answer 46

Sandstones

Question 47

The pore spaces in _______ are generally well-connected, allowing fluids like oil, gas, and water to move relatively freely through the rock matrix.

Answer 47

Sandstones

Question 48

Porosity in sandstones can range from _% to __%, and permeability can vary significantly depending on factors such as grain size, sorting, and the degree of cementation

Answer 48

5 to 30 %

Question 49

form primarily through the accumulation and lithification of biological matcrials like shells, corals, and algae, as well as chemical precipitation of calcium carbonate in marine settings.

Answer 49

Carbonate rocks

Question 50

exhibit highly variable pore properties due to the complex processes that govern their formation.

Answer 50

Carbonate reservoirs

Question 51

often possess a wide range of porosity types, including ntergranular, vuggy, and fracture porosity, resulting from both primary depositional features and secondary alterations such as dissolution, recrystallization, and dolomitization.

Answer 51

Carbonates

Question 52

__________ are generally more predictable and consistent in their reservoir properties __________ are characterized by their complex and heterogeneous nature.

Answer 52

Clastic rocks Carbonate rocks

Question 53

The presence of _____ in a reservoir rock significantly influences its petrophysical properties and, consequently, the reseryoir's capacity to store and transmit hydrocarbons. The impact of clay depends not only on the clay content and the specific mineralogy of the clay minerals but also on the manner in which the clay is distributed within the rock matrix

Answer 53

Clay

Question 54

Types of Clay Distribution

Answer 54

Laminar Clay Dispersed Clay Structural Clay

Question 55

refers to thin clay layers that alternate with sand or other granular materials within the reservoir ock. These clay layers are often deposited during the formation of the rescrvoir, creating a laminated structure.

Answer 55

Laminar Clay

Question 56

Laminar clays typically form barriers to fluid flow, reducing the overall _______ of the reseryoir rock. However, they can still maintain relatively high ______ in the sand layers between the clay laminations.

Answer 56

Permeability Porosity

Question 57

The presence of laminar clay can result in _________ , where the permeability varies depending on the direction of fluid flow.

Answer 57

anisotropy

Question 58

clay that is distributed throughout the pore spaces of the reservoir rock.

Answer 58

Dispersed

Question 59

Dispersed clay is also known as

Answer 59

Authigenic clay

Question 60

This clay can form in place within the pores through chemical processes after the initial sediment deposition, often during diagenesis.

Answer 60

Dispersed

Question 61

significantly reduce the effective porosity and permeability of the reservoir

Answer 61

Dispersed

Question 62

By occupying pore spaces, dispersed clays reduce the available _____ for hydrocarbons and restrict fluid flow by narrowing the _______, which hampers the movement of oil and gas through the reservoir.

Answer 62

Volume Pore throats

Question 63

refers to clay that forms grains and acts as a fundamental rock- building component. In this case, clay minerals are not just an accessory within the pore spaces but are integral to the rock's framework.

Answer 63

Structural Clay

Question 64

Structural clays contribute to the ________ stability of the rock and can influence its physical properties.

Answer 64

Mechanical

Question 65

It alters the overall rock fabric, often resulting in a less porous and less permeable rock. This rock type can have a high volume of clay, leading to low effective porosity and the trapping of fluids within the rock matrix

Answer 65

Structural clay

Question 66

____________ can create directional permeability barriers __________ can reduce effective pore space and fluid flow ___________ fundamentally alter the rock's framework, impacting both storage capacity and fluid transmissibility

Answer 66

Laminar Clay Dispersed clay Structural Clay

Question 67

primarily composed of varying proportions of clay, silt, and sand, exhibit diverse porosity characteristics depending on the relative amounts and distribution of these components.

Answer 67

Clastic Reservoirs

Question 68

is often used to illustrate the composition of clastic sediments in terms of clay, silt, and sand fractions, providing a visual representation of how different mixtures affect porosity.

Answer 68

triangular diagram (ternary diagram)

Question 69

__________ occupies one apex, representing the coarse-grained fraction • __________ occupies another apex, representing the fine-grained, intermediate fraction, • __________ occupies the third apex, representing the very fine-grained fraction

Answer 69

Sand Silt Clay

Question 70

Cores are essential for several reasons:

Answer 70

-Direct Determination of Reservoir Properties - Calibration of Log Measurements - Fundamental Petrophysical Properties

Question 71

Core analysis allows for the direct measurement of key reservoir properties like porosity and permeability. This data is critical for validating and calibrating log-derived interpretations.

Answer 71

Direct Determination of Reservoir Properties

Question 72

Core data can be used to calibrate log measurements, such as nuclear magnetic resonance (NMR)-derived permeability enhancing the accuracy of reservoir models.

Answer 72

Calibration of Log Measurements:

Question 73

Cores provide essential information on parameters like grain density and Archie's parameters, which are vital for interpreting well logs and understanding reservoir characteristicseservoir Properties:

Answer 73

Fundamental Petrophysical Properties:

Question 74

Limitations of Core Measurements

Answer 74

-Limited Representation -Alteration during Coring and Recovery -Sample Preparation Artifacts

Question 75

A core sample represents only a small section of the reservoir and may not be fully representative of the entire formation, especially in heterogeneous reservoirs where rock properties can vary significantly.

Answer 75

Limited Representation

Question 76

The process of coring and core recovery can alter the rock's original stress and temperature conditions, potentially changing its structure and properties.

Answer 76

Alteration During Coring and Recovery

Question 77

Plugging, clcaning, and drying of core samples for laboratory analysis can alter their wettability and potentially change the reservoir rock properties.

Answer 77

Sample Preparation Artifacts

Question 78

are critical factors influencing hydrocarbon production affecting both the physical properties of the fluids within the reservoir and their phase behavior.

Answer 78

Temperature and Pressure

Question 79

The _______________ of hydrocarbon mixtures is highly sensitive to changes in temperature and pressure. The specific phase relationships-whether the hydrocarbons exist as a single liquid phase, a single gas phase, or a mixture of liquid and gas- depend on the types and proportions of hydrocarbons present. Reservoir fluids can range from light, volatile oils and gas condensates to heavy oils and bitumen, each exhibiting unique phase behavior under varying temperature and pressure conditions

Answer 79

Phase behavior

Question 80

is the pressure at which gas begins to come out of solution from the oil when pressure decreases.

Answer 80

Bubble point

Question 81

What forms within the reservoir below the bubble point

Answer 81

Free gas

Question 82

is the pressure at which gas condenses into a liquid as pressure increases.

Answer 82

Dew point

Question 83

Impact on Fluid Viscosities and Mutual Solubility In the reservoir, the viscosities of oil, gas, and water vary with changes in temperature and pressure. For instance, higher temperatures typically _____ the viscosity of oil, making it ___________ to flow. This decreased viscosity can facilitate ______ movement of oil through the reservoir rock, improving its production. Conversely, gas viscosity tends to __________ with pressure but is generally lower than that of oil, allowing it to flow more readily under high-pressure conditions. Water, being less compressible than oil or gas, exhibits relatively _________ viscosity changes across the temperature and pressure ranges encountered in most reservoirs

Answer 83

reduce less resistant Easier Increase Stable

Question 85

Effect on Permeability and Fluid Flow As pressure drops below the bubble point in the reservoir, ________ begin to form in the oil phase. This gas exsolution can significantly affect the fluid flow characteristics in the reservoir rock. The formation of gas bubbles reduces the ______ permeability to oil because the gas occupies pore spaces and blocks pathways that oil would otherwise use to flow. This blockage reduces the relative permeability of the oil, hindering its ability to move through the porous rock. This phenomenon, known as _______________, can cause a substantial decline in oil production rates.

Answer 85

Gas bubbles effective Gas-locking