Describe the different types of wireline logging and their uses?

Well Logging:

Wireline logging is a technique used in the oil and gas industry to gather information about subsurface
formations, reservoir properties, and fluid content in a wellbore. It involves lowering specialized
instruments on a cable (wireline) into the well to measure various properties.

Types of Well logging:

There are several types of wireline logging tools, each designed to measure specific aspects of the
wellbore and surrounding formations. Here are some of the main types of wireline logging and their uses
in detail:

1. Gamma Ray (GR) Logging:

This tool measures natural gamma radiation emitted by formations. Different rock types emit
varying levels of gamma radiation, which can help identify lithology and identify the presence of
radioactive minerals. Shales, for example, typically have higher gamma ray readings due to their
higher content of radioactive materials.
Lithology: refers to the physical and chemical characteristics of rocks and their classification
based on these properties.
Shale: A type of Rock
2. Spontaneous Potential (SP) Logging:
SP logging measures the voltage difference between the wellbore fluid and the surrounding rock
formations. It can provide insights into the salinity and permeability of formation, as well as
detect the presence of movable fluids (e.g., water or hydrocarbons).
Salinity: refers to the concentration of dissolved salts in a fluid, often measured in terms of the
mass of salts per unit volume of the fluid (usually expressed in parts per million or percent). In
the oil and gas industry, salinity commonly refers to the salt concentration in formation water,
which is the water present within the rock formations underground.
Permeability: refers to the ability of a rock to transmit fluids through its pore spaces. It is a
measure of how easily fluids can flow within a rock formation. Permeability is influenced by
factors like pore size, pore connectivity, and the presence of natural fractures or fissures.
3. Resistivity Logging: Resistivity logging tools measure the electrical resistivity of formations.
Different formations have varying resistivity levels due to differences in rock composition,
porosity, and fluid content.
4. Density Logging: Density logging tools use gamma-ray and neutron measurements to determine
the density of the formations. The density of a formation is affected by its composition and
porosity. This information is crucial for calculating the volume of hydrocarbons present in the
reservoir.
5. Neutron Logging: Neutron tools measure the amount of hydrogen in the formation, which is
indicative of fluid content. Hydrogen-rich fluids like water result in higher neutron counts, while
hydrocarbon-bearing formations show lower counts. Neutron logs are often used in conjunction
with density logs to calculate porosity.
 6. Sonic Logging: Sonic tools measure the travel time of sound waves through the formations. By
analyzing the speed of sound, engineers can determine rock porosity, mechanical properties
(such as rock hardness), and identify potential fluid-filled intervals.
7. Caliper Logging: Caliper tools measure the diameter of the borehole. This information is crucial
for understanding the wellbore condition, assessing hole stability, and ensuring proper casing
placement.
8. Temperature Logging: Temperature logs provide information about the temperature profile of
the wellbore and formations. Variations in temperature can indicate the presence of fluid flows
or the geothermal gradient of the area.
9. Formation Pressure Testing: These tools help measure formation pressures and gradients. This
information is essential for determining reservoir fluid characteristics, estimating reservoir
volume, and designing production strategies.

Each type of wireline logging tool provides unique insights into the geological and reservoir properties of
a wellbore. By combining data from various logging runs, engineers and geologists can create a
comprehensive understanding of the subsurface formations, reservoir potential, and fluid content. This
information is crucial for making informed dec isions regarding well completion, production strategies,
and reservoir management.

Formation evaluation is a critical process in the oil and gas industry that involves assessing the properties
and characteristics of rock formations and fluids within a subsurface reservoir. The primary objective of
formation evaluation is to gather information about the reservoir's potential to produce hydrocarbons
(oil and natural gas) and to determine the optimal strategies for extracting these resources efficiently.
This process is essential for making informed decisions during exploration, drilling, and production
phases of oil and gas operations.

Describe formation evaluation and its importance:

Formation evaluation encompasses a variety of techniques and measurements, including:

Well Logging: Logging involves the use of specialized tools that are lowered into a borehole to measure
properties such as electrical resistivity, porosity, permeability, and formation density. These
measurements help to identify the types of rocks present, their composition, and their capacity to store
and transmit fluids.

Coring: Coring involves extracting cylindrical samples of rock formations from the reservoir. These core
samples provide direct information about the rock's texture, mineralogy, and other physical properties
that are crucial for assessing reservoir quality and behavior.

Fluid Sampling and Analysis: Fluids extracted from the reservoir, such as oil, gas, and formation water,
are analyzed to determine their composition, phase behavior, and properties. This information aids in
understanding the nature of the resources and their behavior under various conditions.

Geophysical Surveys: Techniques like seismic imaging provide a macroscopic view of subsurface
structures, helping to identify potential reservoirs and assess their geological characteristics.
Reservoir Simulation: Once the data is collected, it's often used to create computer models that
simulate the behavior of fluids within the reservoir under different scenarios. These simulations aid in
optimizing production strategies.

Importance of Formation Evaluation:

Reservoir Characterization: Formation evaluation allows geoscientists and engineers to understand the
geological and petrophysical properties of the reservoir. This information is crucial for estimating the
amount of recoverable hydrocarbons, predicting reservoir behavior, and designing effective production
strategies.

Resource Estimation: Accurate estimation of the volume of hydrocarbons present in the reservoir is
essential for making investment decisions, planning drilling programs, and assessing the economic
viability of a project.

Production Optimization: Formation evaluation data helps in identifying the most productive zones
within a reservoir, optimizing well placement, and determining the optimal methods for extracting
hydrocarbons while minimizing operational challenges.

Risk Reduction: Comprehensive formation evaluation reduces uncertainties and risks associated with
drilling and production. It helps in avoiding costly mistakes, such as drilling dry or uneconomical wells.

Reservoir Management: Continuous monitoring and updating of formation evaluation data throughout
the field's lifespan enable effective reservoir management, leading to better decision-making for
enhanced oil recovery techniques.

In summary, formation evaluation is a fundamental aspect of the oil and gas industry, providing critical
insights into reservoir properties and behavior. It informs decision-making at every stage of exploration
and production, contributing to efficient resource extraction and maximizing the economic potential of
oil and gas fields.

How are formations evaluated using open hole wireline tools?

Formations are evaluated using openhole wireline tools by deploying these tools into the wellbore (the
drilled hole) to collect data about the properties of the subsurface formations. Openhole wireline tools
are specialized instruments that are lowered into the well on a cable (wireline) to measure various
characteristics of the formations. Here's an overview of the process:

Deployment: After the drilling process has created the wellbore, the drill string is removed, leaving an
open hole. Openhole wireline tools are then assembled and attached to the wireline cable. The tools are
designed to fit through the well's openhole and reach the desired depth.

Lowering the Tools: The wireline cable, connected to the tools, is lowered into the wellbore. The tools
are designed to be versatile and capable of collecting data from different depths within the well.

Data Collection: As the wireline tools descend through the well, they collect data about various
formation properties. These properties may include:

Porosity: Nuclear tools (neutron and density tools) measure the interaction of particles with the
formation's nuclei to determine the porosity, or the amount of pore space within the rocks.
Lithology: Tools that measure natural gamma radiation can identify different rock types based on their
characteristic radiation signatures.

Fluid Content: Certain tools can provide insights into the presence of fluids within the formation, helping
to determine the potential for hydrocarbon reservoirs.

Resistivity: Resistivity tools measure the electrical properties of the rocks, which can indicate the
presence of fluids and the rock's permeability.

Pressure and Temperature: Some tools can measure downhole pressure and temperature, providing
important information about the reservoir's conditions.

Imaging: Imaging tools, such as microresistivity imaging or sonic tools, can create detailed images of the
borehole walls and surrounding formations.

Real-Time Data Transmission: In some cases, the data collected by the wireline tools can be transmitted
in real time to the surface, allowing engineers and geologists to monitor the data as the tools move
through the wellbore.

Analysis and Interpretation: The data collected by the openhole wireline tools is analyzed and
interpreted by experts. The information helps geologists and engineers understand the characteristics of
the formations, identify potential reservoir zones, assess the presence of fluids, and make decisions
about the viability of resource extraction.

Decision-Making: The insights gained from the wireline data play a crucial role in making informed
decisions about whether the well should be completed for production, where to place production zones,
and how to optimize drilling and production strategies.

In summary, openhole wireline tools provide a means of collecting valuable data from the wellbore's
openhole. This data is instrumental in understanding the subsurface geology, evaluating reservoir
potential, and making strategic decisions for resource extraction in the oil and gas industry.

How each type of wireline tool measures formation properties?

Nuclear Tools (Neutron and Density Tools):

Neutron Tools: Neutron tools work based on the interaction between neutrons and atomic nuclei in the
formation. These tools emit a stream of high-energy neutrons into the formation. Neutrons collide with
the nuclei of atoms in the formation, and some of them are scattered back towards the tool. The rate of
scattering depends on the density of the formation. Hydrogen-rich fluids, such as water, slow down
neutrons more than denser rock formations. By measuring the rate of returning scattered neutrons, the
tool can determine the formation's hydrogen index, which is related to porosity.

Density Tools: Density tools use gamma-ray photons to measure the bulk density of the formation.
These tools emit gamma rays into the formation, and some of these gamma rays are scattered back
towards the tool. The gamma rays that are scattered back are detected and used to calculate the bulk
density of the rock. Denser rocks will scatter more gamma rays, indicating a higher density.

Gamma Ray Tools:

Gamma ray tools measure the natural gamma radiation emitted by the formation's rocks. Certain
isotopes within the rocks emit gamma rays, and the intensity of these gamma rays varies depending on
the types of isotopes present. Different rock types contain different isotopes, and these isotopes decay
at different rates. By measuring the gamma ray intensity, the tool can identify and differentiate between
various rock formations. Shale, for example, tends to have a higher gamma ray signature due to the
presence of radioactive isotopes like potassium-40.

Resistivity Tools:

Resistivity tools measure the electrical resistivity of the formation. These tools emit an electrical current
into the formation and measure the resistance encountered. Formation resistivity is influenced by the
presence of fluids and the conductivity of the rock. Water is a good conductor of electricity, so a
formation with high water content will have low resistivity. Hydrocarbons, on the other hand, are poor
conductors, leading to higher resistivity readings. The tool provides information about the fluids present
and the rock's permeability.

Imaging Tools (Microresistivity Imaging and Sonic Tools):

Microresistivity Imaging Tools: These tools create images of the borehole walls and the formations
surrounding it. They use arrays of small electrodes or sensors to measure the resistivity of the
formations at various azimuthal angles. By rotating the tool and taking measurements at different
orientations, a detailed image of the borehole can be generated, showing the different rock layers,
fractures, and other features.

Sonic Tools: Sonic tools emit sound waves into the formation and measure the time it takes for the
waves to travel through the rock and return to the tool. The speed of sound is affected by the rock's
density and elastic properties. These measurements can provide information about rock porosity,
lithology, and mechanical properties.

Pressure and Temperature Tools:

These tools measure downhole pressure and temperature. They provide valuable information about the
reservoir's conditions, such as pressure gradients, temperature gradients, and the presence of any
abnormal pressure zones. This data helps in understanding reservoir behavior and optimizing production
strategies.
How each tool provides different and critical information?

Nuclear Tools (Neutron and Density Tools):

Critical Information:

Porosity: Neutron tools provide crucial information about porosity by measuring the hydrogen index of
the formation. Hydrogen-rich fluids like water contribute significantly to porosity, and this tool helps
estimate the volume of pore space available for fluid storage.

Lithology: While neutron tools primarily focus on hydrogen content, density tools measure the overall
bulk density of the formation. This information is valuable for identifying different rock types, as
different minerals have distinct density signatures.

Gamma Ray Tools:

Critical Information:

Formation Identification: Gamma ray tools are essential for identifying and correlating different rock
formations. By measuring the natural gamma radiation emitted by various isotopes in rocks, these tools
help create a detailed geological log of the well, aiding in stratigraphic analysis and identifying potential
zones of interest.

Shale Identification: Gamma ray measurements are particularly useful for identifying shale layers. Shale
has higher gamma ray values due to the presence of radioactive isotopes. The presence of shale is
important for well stability and drilling decisions.

Resistivity Tools:

Critical Information:

Fluid Content: Resistivity tools provide insights into the fluid content of the formation. High resistivity
readings suggest low water content and the potential presence of hydrocarbons. Low resistivity indicates
higher water saturation.

Permeability Estimation: By evaluating the resistivity, engineers can estimate the rock's permeability,
which is crucial for understanding how easily fluids can flow through the formation.

Imaging Tools (Microresistivity Imaging and Sonic Tools):

Critical Information:

Formation Characterization: Imaging tools offer detailed images of the borehole walls and surrounding
formations. These images provide information about the structure, fractures, bedding planes, and other
geological features. This data is essential for understanding the geometry and integrity of the reservoir.

Fracture Identification: Micro resistivity imaging can identify natural fractures, which are vital as they can
serve as pathways for fluid flow, affecting reservoir behavior and production strategies.

Pressure and Temperature Tools:

Critical Information:

Reservoir Behavior: Pressure and temperature data provide insights into the behavior of the reservoir.
Abnormal pressure zones, pressure gradients, and temperature variations can indicate different reservoir
compartments or fluid movement patterns.

Well Integrity: Monitoring pressure and temperature can help detect any potential issues with well
integrity, such as fluid migration or wellbore instability.

Open-Hole to Cased Hole Transition: In oil and gas drilling, the open-hole refers to the uncased section
of the wellbore that is drilled through the rock formations. After drilling, when the desired depth is
reached and the wellbore needs to be stabilized and protected, a steel casing is inserted into the
wellbore. This process is called "casing." The casing is a pipe made of steel that is inserted into the drilled
hole and cemented in place to create a barrier between the wellbore and the surrounding rock
formations. This is done to prevent well collapse, protect groundwater, and manage reservoir fluids
efficiently. Once the casing is installed and cemented, the section of the wellbore above the casing
becomes cased hole.

Functions of Cased Hole Tools: Cased hole tools are specialized instruments used for well logging and
diagnostics after the casing has been installed. These tools are lowered into the wellbore on a wireline,
which is a thin cable used to deploy and retrieve the tools. Some functions of cased hole tools include:

Casing Inspection: Cased hole tools can assess the integrity of the casing and identify potential problems
such as corrosion, wear, or breaches that could lead to fluid leakage.

Production Logging: These tools can measure fluid flow rates, fluid density, and other parameters to
evaluate the performance of the well and identify zones contributing to production or injection issues.

Noise and Vibration Analysis: Cased hole tools can detect vibrations or noises in the well that might
indicate issues such as equipment malfunctions, fluid flow problems, or reservoir changes.

Pressure and Temperature Measurements: Tools can record pressure and temperature profiles at
different depths in the well, providing insight into fluid behavior and reservoir characteristics.

Perforation Evaluation: Cased hole tools can evaluate the effectiveness of perforations made in the
casing to allow reservoir fluids to flow into the wellbore.

Fluid Sampling: Some tools can retrieve fluid samples from different depths in the well, aiding in
understanding the fluid composition and reservoir properties.

Halliburton CAST for Casing Integrity Monitoring: The Halliburton CAST (Cased Hole Analysis and
Stratified Technology) is a system used to monitor casing integrity. It employs advanced acoustic and
electromagnetic technologies to assess the condition of the casing, identify corrosion, measure casing
thickness, and detect casing deformation. By continuously monitoring casing integrity, operators can
ensure that the well remains stable and that there are no risks of leaks or structural failures.

Software Tools for Downhole Forces and Intervention Programs: Software tools play a crucial role in
analyzing downhole mechanical and hydraulic forces. These tools simulate and model the forces exerted
on the well casing and completion equipment due to production, injection, and reservoir dynamics. This
information helps in understanding potential stresses and strains on the well components. By using
these models, intervention programs can be developed that address production challenges effectively.
These programs might involve activities such as adjusting production rates, optimizing completion
designs, or implementing remedial actions to enhance production efficiency and maintain well integrity.

Casing Inspection Tools:

Casing Collar Locator (CCL): This tool helps locate the position of casing collars, which are thicker
sections of the casing joints. It provides depth control for other tools and assists in identifying casing
wear, deformation, or damage.

Casing Gamma Ray Tools: These tools measure gamma radiation levels to identify casing thickness and
evaluate corrosion or scale buildup on the casing's interior surface.
Production Logging Tools:

1) Spinner Flowmeter: This tool measures fluid velocity and flow rates across the perforated intervals
or production zones in the well. It helps identify which zones contribute to or impede production.
2) Noise Logging Tool: Detects acoustic signals produced by fluid flow or mechanical interactions within
the well. It helps locate fluid entry points, evaluate downhole equipment condition, and diagnose
issues like gas or water breakthrough.
3) Temperature and Pressure Gauges: These tools measure temperature and pressure variations at
different depths to analyze fluid behavior and identify potential obstructions or crossflows.

Noise and Vibration Tools:

Acoustic and Seismic Tools: These tools record noise and seismic vibrations to detect anomalies, such as
fluid entry, casing leaks, or equipment malfunctions. They provide valuable information about well
integrity and flow dynamics.

Cement Evaluation Tools:

Cement Bond Log (CBL) Tool: Used to assess the quality of cement bonding between the casing and the
wellbore wall. It helps identify zones of poor cement integrity that might require remedial cementing.

Fluid Sampling Tools:

Sampler Tools: These tools collect fluid samples from specific intervals in the well. The samples provide
insights into fluid composition, reservoir properties, and potential production issues.

Pressure and Temperature Tools:

Pressure and Temperature Gauges: Tools equipped with sensors to measure downhole pressure and
temperature at various depths. This data helps analyze reservoir behavior, fluid movement, and
production performance.

Perforation Evaluation Tools:

Casing Inspection Tools with Caliper Measurement: Some casing inspection tools include caliper
measurements that assess the internal diameter of the casing and the condition of perforations.

Cased Hole Electromagnetic Tools:

Electromagnetic Thickness Tools: These tools use electromagnetic fields to measure casing thickness and
detect potential corrosion or damage.

Production Optimization Tools:

Chemical Injection Tools: Tools designed for delivering chemicals or treatments directly into the well to
optimize production by mitigating issues like scaling, paraffin buildup, or corrosion.

Multi-Function Tools:

Multi-Finger Caliper Tools: These tools have multiple extendable fingers that can measure casing
diameter, identify deformities, and assess the condition of casing walls.
Each type of cased-hole tool serves a specific purpose in assessing well integrity, understanding reservoir
behavior, diagnosing production challenges, and optimizing production strategies. By utilizing a
combination of these tools, operators can gather comprehensive data to make informed decisions about
maintaining well performance, addressing issues promptly, and ensuring the longevity of the wellbore
and associated equipment.

Module 5:Well Equipment and Well Intervention

Attaching Logging Tools and Checking Attachments:

Attaching logging tools to the wireline is a crucial step in wireline operations. Logging tools are
specialized instruments used to measure properties of the wellbore and surrounding formations. Proper
attachment ensures that the tools are secure and won't disconnect during deployment or retrieval. This
prevents accidents, tool loss, and potential damage to the well. Checking the attachments involves
thorough inspection to confirm that the tools are correctly connected and ready for use.

Understanding Weakpoint:

A "weakpoint" in wireline operations is a deliberate point of reduced strength in the wireline. It's
designed to break under a specific tension to facilitate the retrieval of stuck tools. If tools get stuck
downhole, applying tension can break the weakpoint, allowing the retrieval of the wireline and tools.
Understanding the concept of a weakpoint is vital because it enables operators to free stuck tools
without leaving them in the well, which can be costly and time-consuming.

Cased-Hole Intervention Logging:

Cased-hole intervention logging refers to performing logging operations in wells that have been
previously cased with steel pipe. In contrast, open-hole logging is done in uncased sections. Cased-hole
logging often involves logging through perforations in the casing or using specialized tools that can
navigate within the casing. This allows for evaluation of the production zones and helps operators make
informed decisions about the well's productivity and potential issues.

Wireline Hydraulic Systems:

Wireline hydraulic systems are used to control the movement of wireline tools downhole and their
retrieval. These systems use hydraulic pressure to actuate tools and mechanisms, making operations
smoother and more controlled. The module likely explains the different types of hydraulic systems used
in wireline operations and how they function.

Wellhead Pressure Control - Christmas Tree and BOP Stack:

The "Christmas Tree" is a set of valves, spools, and fittings installed at the wellhead. It's used to control
the flow of fluids into and out of the well. During wireline interventions, maintaining proper wellhead
pressure control is crucial to prevent uncontrolled fluid flow, which could lead to accidents or equipment
damage. The Blowout Preventer (BOP) stack is another safety mechanism that can seal the well in case
of unexpected pressure surges or kicks. Both the Christmas Tree and the BOP stack contribute to
ensuring the safety of the operation.

Maintaining Grease Pressure:

Grease is injected into the well during wireline operations to prevent fluid migration within the wellbore
and to provide lubrication for the wireline as it moves in and out. Maintaining proper grease pressure is
important as it ensures that the grease effectively seals the well and reduces friction on the wireline.
This prevents the potential for fluid influx or loss zones that could lead to operational issues.

Attachment of Tools to the Wireline: Attaching tools to the wireline is a crucial step in wireline
operations. Various types of specialized tools are used for logging, measuring, and performing
interventions in wells. These tools need to be securely attached to the wireline before they are lowered
into the wellbore. Proper attachment involves using appropriate connectors and ensuring that the tools
are firmly secured. This prevents the tools from becoming detached during deployment, which could
lead to loss of tools downhole or operational issues.

Lowering Tools into the Hole on a Wireline: Lowering tools into the wellbore on a wireline involves using
a winch or hoist system. The wireline is spooled onto a drum of the winch, and the tools are attached to
the bottom end of the wireline. As the winch is operated, the wireline is payed out, allowing the tools to
be lowered gradually into the wellbore. Proper control of the winch speed is crucial to ensure the tools
are lowered at a controlled rate, preventing any sudden jolts or impacts that could damage the tools or
the well.

Hydraulic Systems: Hydraulic systems in wireline operations play a pivotal role in controlling various
downhole tools and mechanisms. These systems use hydraulic fluid to generate pressure, which is then
used to actuate tools such as valves, arms, and other mechanical components. Hydraulic control ensures
precise manipulation of tools even in deep and complex well environments. The hydraulic system can be
controlled from the surface, allowing operators to remotely control tool actions and responses
downhole.

Well Intervention Equipment: Well intervention equipment refers to the tools, devices, and systems
used to perform maintenance, measurements, and operations within a well after it has been drilled and
completed. This equipment includes various tools designed to enter the wellbore, perform
measurements, take samples, and make repairs. Some common types of well intervention equipment
include:

Logging Tools: Specialized instruments that measure parameters such as formation resistivity, porosity,
and fluid properties.

Fishing Tools: Used to retrieve lost or stuck tools, equipment, or debris from the wellbore.

Perforation Tools: Used to create openings in the casing to allow fluid flow between the reservoir and
the wellbore.

Packers: Sealing devices that isolate specific sections of the wellbore, allowing for controlled fluid
injection or production.

Pressure-Control Equipment: Including Blowout Preventers (BOPs) and Christmas Trees, which regulate
wellbore pressure and control fluid flow during interventions.

Coring Tools: Used to take samples of rock formations for analysis.

Remediation Tools: Devices designed to clean, stimulate, or repair wellbores to improve production.
In summary, these topics are all crucial components of wireline operations and well interventions.
Properly attaching tools to the wireline, lowering tools with precision, understanding hydraulic systems,
and using appropriate well intervention equipment all contribute to the success, safety, and efficiency of
wellbore activities.

Attachment of Tools to the Wireline:

Attaching tools to the wireline is a fundamental step in well intervention. Well intervention involves
various operations performed to maintain, repair, or enhance the production of a well. To attach tools:

Tool Selection: Depending on the specific intervention goals, appropriate tools are selected. These tools
could include logging instruments, perforating guns, packers, and other specialized equipment.

Tool String Assembly: The selected tools are assembled into a "tool string." This assembly might involve
connecting multiple tools in a specific order to achieve the desired intervention tasks.

Tool String Connection: Each tool is securely connected to the wireline. This connection often involves
threaded connections or other mechanisms to prevent tools from disconnecting during operation.

Quality Checks: Before lowering the tool string into the well, thorough checks are conducted to ensure
that each tool is properly attached, connections are secure, and all components are in working
condition.

Lowering Tools into the Hole on a Wireline:

Lowering tools into the wellbore on a wireline, often referred to as "running the tools," is a critical phase
in well intervention:

Winch Operation: The winch is a device used to spool and control the wireline's movement. It's
operated to lower the tool string into the well.

Depth Control: Precise depth control is maintained to position the tools at the desired location within
the well. Depth measurements and control mechanisms help ensure accurate tool placement.

Wireline Movement: The wireline is gradually paid out from the winch as the tools are lowered. The
operator monitors and controls the speed of descent to prevent sudden jerks or slack in the wireline,
which could lead to tool misplacement or damage.

Hydraulic Systems:

Hydraulic systems are employed in well intervention for various purposes, including tool actuation,
movement, and control:

Wireline Pressure Control: Hydraulic systems are used to apply controlled pressure to the wireline. This
pressure can actuate tools, such as setting packers or firing perforating guns.

Tool Functions: Hydraulic power can enable functions like tool rotation, opening and closing of valves,
and other tool-specific actions.

Safety Mechanisms: Some hydraulic systems include safety features that prevent unintended tool
movement or activation. This ensures that tools are only operated when intended.
Pressure Monitoring: Operators monitor hydraulic pressure to ensure that tools are functioning correctly
and to prevent overexertion that could lead to equipment failure.

Well Intervention Equipment:

Well intervention equipment encompasses a wide range of tools and technologies designed for specific
intervention tasks:

Logging Tools: Instruments used for collecting data about the wellbore, formation properties, and fluid
content.

Perforating Guns: Tools that create holes in the casing to allow reservoir fluids to flow into the wellbore.

Packers: Devices that isolate specific sections of the wellbore, facilitating tasks like zonal isolation or
pressure testing.

Fishing Tools: Instruments designed to retrieve stuck tools or debris from the wellbore.

Control Panels: Interface devices that enable operators to control hydraulic systems, monitor tool
functions, and manage interventions safely.

Module 6: Tool Safety

Importance of Safety on the Rig:

The sixth module emphasizes that safety is the utmost priority when working on a rig. Safety protocols
are in place to protect personnel, equipment, and the environment. This module sets the foundation for
understanding how crucial it is to follow safety procedures rigorously throughout all wireline operations.

Communication and Double Checking:

Effective communication and double checking are emphasized as vital safety practices. Clear
communication ensures that all team members understand their roles, tasks, and potential hazards.
Double checking involves reviewing critical steps, connections, and equipment to verify that everything
is in order before proceeding with any operation. These practices reduce the likelihood of errors that can
lead to accidents or injuries.

Awareness and Incident Prevention:

The module underscores the importance of awareness in preventing incidents or injuries. Being attentive
to surroundings, equipment conditions, and potential hazards helps operators anticipate and mitigate
risks. Heightened awareness can prevent accidents and ensure swift responses in case of emergencies.

Radioactive Tools and Explosive Tools Rules:

Certain wireline tools, such as those containing radioactive sources for well logging or explosive tools
used for perforation, have specific safety rules due to their inherent risks:

Radioactive Tools: Tools that use radioactive sources for measurements are subject to strict handling,
storage, and disposal protocols. Operators must be trained to minimize exposure to radiation and to
prevent contamination.
Explosive Tools: Tools like perforating guns use explosive charges. Operators must follow stringent
guidelines for safe handling, transportation, and deployment to avoid accidental detonations.

Static Electricity and Fluid/Pressure Testing Tools:

The module likely highlights the risk of static electricity during wireline operations, particularly in
flammable environments. Proper grounding practices and precautions to prevent static discharge are
covered. Fluid and pressure testing tools can pose risks due to high pressures involved. Adhering to
correct procedures and using appropriate equipment reduces the chance of accidents during these tasks.

Dangers of H2S Gas:

The module addresses the extreme dangers of hydrogen sulfide (H2S) gas, a toxic and potentially lethal
gas commonly found in oil and gas wells. H2S is colorless and highly poisonous even at low
concentrations. Proper precautions, such as using personal protective equipment (PPE) like respirators,
monitoring H2S levels, and ensuring proper ventilation, are vital when dealing with wells that may
contain this gas.

Simple Safety Steps and Saving Lives:

The module concludes by emphasizing that adhering to simple safety steps can save lives. Proper
training, vigilant communication, adherence to safety procedures, and a strong safety culture contribute
to incident prevention and the well-being of all rig personnel.

Basic Wireline Tool Safety:

Basic wireline tool safety encompasses a range of practices and protocols that are crucial to ensure the
well-being of personnel and the successful execution of wireline operations. Some key aspects include:

Personal Protective Equipment (PPE): Rig personnel should wear appropriate PPE, such as gloves, safety
glasses, helmets, flame-resistant clothing, and hearing protection, to protect against various hazards.

Training and Certification: All personnel involved in wireline operations should receive proper training
and certification. This ensures that they are familiar with the equipment, procedures, and safety
measures.

Communication: Clear communication is essential among all team members. Operators need to
understand their roles, responsibilities, and potential hazards. Open lines of communication help
prevent misunderstandings that could lead to accidents.

Tool Inspection: Thoroughly inspect tools before use. Check for any signs of damage, wear, or
malfunction. Defective tools should not be used and must be reported for repair or replacement.

Secure Attachments: Ensure that tools are properly attached to the wireline and that connections are
secure. Loose tools or faulty connections can lead to accidents during deployment or retrieval.

Proper Handling: Handle tools with care to prevent dropping or mishandling. Some tools may contain
fragile or sensitive components that can be damaged easily.

Emergency Procedures: Familiarize personnel with emergency procedures, including evacuation plans,
first aid, and how to respond to potential incidents.
Specific Safety Procedures for Hazardous Tools:

Tools that present unique hazards, such as radioactive or explosive tools, require specific safety
procedures:

Radioactive Tools: When dealing with tools containing radioactive sources for well logging, workers
should limit exposure and follow radiation safety protocols. Minimize time spent near the source,
maintain distance, and use shielding. Proper storage, transportation, and disposal of radioactive
materials are also vital.

Explosive Tools: Safety measures for explosive tools include proper handling, storage, and transportation
of explosive charges. Operators should follow strict guidelines to prevent accidental detonation and
ensure safe deployment.

Pressure Control When Operating a Wireline:

Maintaining pressure control during wireline operations is crucial for preventing accidents, blowouts,
and other dangerous situations:

Well Control Equipment: The wellhead equipment, including the Christmas Tree and Blowout Preventer
(BOP) stack, is used to control pressure during wireline operations. The BOP stack can shut off the well in
case of unexpected pressure surges.

Grease Injection: Grease is injected into the well to maintain wellhead pressure and prevent fluid
migration. Proper grease pressure ensures that wellbore fluids do not escape uncontrollably.

Pressure Monitoring: Operators monitor wellhead pressure continuously during wireline operations.
Pressure spikes could indicate a potential issue downhole, requiring immediate action to avoid
equipment damage or personnel injury.

Pressure Control Tools: Some wireline tools are designed to regulate pressure within the wellbore. These
tools can help manage pressure changes during logging or intervention tasks.

Emergency Shutdown: In the event of pressure anomalies or unexpected well behavior, there should be
established procedures for emergency shutdown to prevent further escalation.

Drilling Oil and Gas:

Drilling an oil well involves several steps, and the process can vary depending on factors like the depth of
the well, the geological formations encountered, and the specific techniques used. Here's a general
overview of the steps involved in drilling an oil well, including casing and production tubing installation:

Site Preparation: The drilling process begins with selecting a suitable location for the well. The site is
cleared and leveled, and access roads are built.

Rig Setup: A drilling rig is brought to the site and set up. The rig includes equipment like the derrick
(tower-like structure), drill bit, drilling mud system, and hoisting machinery.

Spudding In: The process starts with "spudding in," which involves drilling a shallow hole, usually around
100-200 feet deep, to provide stability for the larger drilling equipment.
Drilling the Wellbore: The drilling rig uses a rotating drill bit attached to the drill string to create the
wellbore. As drilling progresses, drilling mud is pumped down the drill string to cool the bit, lift rock
cuttings to the surface, and maintain pressure to prevent blowouts.

Installing Casing: After drilling a certain depth, a steel casing string is inserted into the wellbore and
cemented in place. Casing serves to prevent the collapse of the wellbore, isolate formations with
different pressures, and prevent the migration of fluids between different zones.

The casing typically consists of multiple sections:

Conductor Casing: The first casing installed, usually shallow, to stabilize the upper section of the
wellbore.

Surface Casing: The next casing layer to isolate shallow groundwater and other formations.

Intermediate Casing: Additional casing layers installed to isolate specific formations.

Production Casing: The final casing string, which extends down to the production zone.

Drilling Continuation: Drilling continues, often in stages, with the use of different drill bits to reach
deeper formations. Drilling mud is adjusted to match the formation's characteristics and maintain
pressure control.

Completion and Production Tubing: Once the desired depth is reached, the well is prepared for
production:

Perforating: Small holes are created in the casing and cement to allow oil or gas to flow into the
wellbore.

Production Tubing Installation: A production tubing string is inserted through the casing into the
wellbore. This tubing carries the produced fluids (oil, gas, or a mixture) to the surface.

Well Completion: Various completion equipment is installed, including packers, valves, and other
devices to control and manage the flow of fluids from the reservoir.

Production and Monitoring: With the well completed, it's ready for production. Monitoring equipment
is often installed to track production rates, pressure, and other parameters.
 Pressure control equipment:
As per API standards there should be a minimum of two barriers.
The pressure control employed during wireline operations is intended to contain pressure
originating from the well bore. During open hole electric line operations, the pressure might be
the result from a well kicking. During cased hole electric line, this is most likely the result of a
well producing at high pressures. Pressure equipment must be rated well over the expected well
pressures. Normal ratings for wireline pressure equipment is 5,000, 10,000, and 15,000 pounds
per square inch. Some wells are contained with 20,000 psi and 30,000 psi equipment is in
development also.
Equipment is usually chosen to have a Working Pressure Rating of 1.2 times the maximum
expected well pressure.
Pressure tests the complete set up to 1.2 times the expected wellhead pressure. Hold pressure for
10 minutes and record. Use water or glycol to test and NEVER diesel. Ensure that no air remains
in the system during a pressure test.
Maximum Allowable Working Pressure during the job equals the well-site test pressure.
Maximum allowable operating pressure should is pressure at which equipment was tested at well
site prior to job.
Flange:
A flange attaches to the top of the Christmas tree, usually with some sort of adapter for the rest
of the pressure control. A metal gasket is placed between the top of the Christmas tree and the
flange to keep in well pressures.
Pump-In Sub:
Pump-in subs (also known as a flow T) allow for the injection of fluid into the pressure control
string. Normally these are used for wellsite pressure testing, which is typically performed
between every run into the well. They can also be used to bleed off pressure from the string after
a run in the well, or to pump in kill fluids to control a wild well.
Grease injection control head:
Prevents well pressure to escape to atmosphere.
Grease tube (which is below inlet of grease injection control head) has less clearance than other
flow tube which prevents flowing of grease from high pressure to low pressure.
To prepare for operations, the wireline is threaded through the components of the Elmar Grease
Injection Control Head before the rope socket and wireline head are made up. When entering a
well under pressure, viscous grease is injected into the flotubes at a pressure minimum 20%
greater than the existing well pressure. The grease fills the annular space between the inner wall
of the flotube and the outside surface of the wireline, forming a liquid seal that contains the well
fluids while allowing wireline movement.
Grease Injection Equipment consists of a set of flotubes and couplings which are mounted
below the stuffing box. There are two different types of flotube in common use, solid type
flotubes and concentric flotubes. Both types do the same job and work in the same way but are of
a different construction. This manual covers the concentric flotube type. The concentric type
flotube is made up of flotubes and flotube sleeves. The flow tube is slightly longer than the
sleeve and is sealed with an o-ring at both ends of the GIE coupling. The flow tube sleeve fits
over the flotube and also seals by an o-ring at either end of the GIE coupling. With the
concentric design it is possible to change the flotube more often, thus maintaining optimum
clearance. The tubes must be matched to the size of the wireline in use, taking into account any
wear on the wireline. Thus, for each nominal wireline size there is a choice of tubes. The
supervisor must decide what size tubes are most appropriate for the cable. For example, a brand
new 7/32” cable will probably require flotubes that have an ID of 0.226”. After the first five to
ten jobs the cable will stretch and become slightly worn. The cable will then possibly pass
through the 0.222” flotubes. As the cable approaches the end of its life, the outer strands may
become very worn and flattened and the 0.219” flotubes may be used.
In gas more flotubes must be used, as it is easier for gas to break through the grease and push it
out as the gas expands. If the flotube length is not adequate, grease consumption increases, and it
is difficult or impossible to establish a seal.
The pressure seal is maintained by a flow of thick, viscous grease which is pumped into the small
annular space between the cable and the inner wall of the flotube. The annular space is very
small, i.e. between +0.002” and +0.008” difference in the diameter. In practice, small amounts of
grease are lost at both ends, particularly when the cable is moving, while well fluids are
contained.
The well site TP shall be 1.2 times maximum potential wellhead pressure (MPWHP). If no
wellhead pressure is expected, the equipment shall be tested at 25% of its WP rating. All well
site pressure testing and the pressure test values obtained shall be noted on the equipment service
report. The use of a pressure recorder (chart or film) is recommended during well site pressure
testing.
ENVIRO:
The ASEP Elmar Enviro Combination Stuffing Box and Line Wiper is designed for use with
wireline grease injection control heads, for wiping excess grease from the moving wire and for
packing off on a stationary wire. The Enviro Combination Stuffing Box and Line Wiper is
mounted immediately above the Grease Injection Head. Unlike the conventional set-up, the
Enviro stuffing box is located above the line wiper, which helps to increase line wiper efficiency
and reduce grease spillage, resulting in cleaner wire, less grease escaping from the assembly and
a cleaner worksite/derrick. The stuffing box section is used to seal around the cable in an
emergency or when the cable will be stationary for an extended period of time. The device
remains open during normal operation. Directly below the stuffing box is the line wiper which
removes excess grease from the surface of the moving cable. As the grease is wiped off the cable, it
passes down inside the lower body. A manifold fitted to the base of the line wiper is used to return the
grease back to the control module.

The line wiper rubber is larger than the stuffing box packing and requires a much lower hydraulic
pressure to operate. This prevents the rubber crushing/stripping the moving cable, and instead is
sufficient to remove excess grease from the surface of the wire.

The cable is not free to move when the stuffing box packings are activated. Any attempt to close the
stuffing box packing around a moving cable could cause the outer strands to 'bird cage' or break.

Elmar supply nitrile elastomers as standard on our seal kits.

For 10Kpsi WP Enviro SB/LW Assy:

Line wiper normal operating pressure 200-500PSI
Line wiper maximum working pressure 3000 psi
Stuffing box normal operating pressure 3000 psi
Stuffing box maximum working pressure 5000 psi

For 10Kpsi WP Enviro SB/LW Assy Line wiper normal operating pressure 200 - 500 psi Line wiper
maximum working pressure 3000 psi Stuffing box normal operating pressure 3000 psi Stuffing box
maximum working pressure 5000 psi

The operator must ensure they are aware of the maximum hydraulic operating pressures for both the
stuffing box and the line wiper before using the equipment.

Lubricator:

Ensure that enough lubricators are available to cover the tool and allow 3ft (1 meter) clearance.

Tool Catcher:

The NOV Elmar Hydraulic Wireline Tool Catcher is a device which has been designed for use as part of a
complete wireline intervention string. The tool catcher is typically positioned below the ball check valve
and above the lubricator. The primary purpose is as a safety device for installation below the grease
injection head or slickline stuffing box. If the tool is pulled into the top of the lubricator and the wire
stripped from the rope socket, the tool catcher will engage the tool’s fishing neck and prevent the loss of
the tool string into the well bore. This can save a potentially expensive fishing operation. The tool
catcher is designed to be fail-safe: it is permanently in the catch position and requires no hydraulic
pressure to catch. To release the tool, hydraulic pressure is applied which opens the collets and frees the
tool. Once the tool is released the hydraulic pressure should be removed to reset the tool catcher to the
catch position

Operating Hydraulic Pressure: 1200 psi

Hydraulic Pressure: 3,000 psi maximum

BOP:

The NOV Elmar Compact Wireline Valves (Patent Pending), or BOP’s, have been designed for use as part
of a complete wireline intervention string. The primary purpose is to provide a manageable safety
barrier during remedial work on a wireline. The valves are designed to control well pressure by sealing
around the wireline cable.

Maximum hydraulic working pressure 3,000 psi.

Lubricator:

Standard lengths are 4,6,8,10 and 12 feet.

ID should be 0.15” to 0.25” larger than tool maximum OD.

Maximum length is tool length plus 3 feet.