Some of the best tips for oil and gas well drilling experts:

“Listening and listening well well during drilling reduces a large proportion of the associated and expected problems”

Mud Logging is one of the most significant strategies for listening to wells during various drilling operations since it is regarded as the black box for all that goes on and happens from various operations.

It collects rock samples and drilling products that come to the surface and precisely captures all data and operations to build a complete detailed record of everything that happens in the subsurface.

Mud Logging Definition

Mud logging: is a service that qualitatively and quantitatively obtains data from, and makes observations of,

1- Drilled rocks,

2- Drilling fluids and

3- Drilling parameters

 The mud logging unit is the information center on the rig site to serve both exploration and drilling departments.

Mud Logging General Purposes

Mud logging has many basic goals: it identifies potentially productive hydrocarbon-bearing formations, it identifies marker or correlatability geological formations, and it provides data to the driller that allows for safe and cost-effective operations. The following are some of the actions taken to achieve these goals:

• Drill cuttings are being collected.
• Describe the cuts in detail.
• Interpreting the described cuttings (lithology).
• Estimating drilled formation parameters such as porosity and permeability.
• Maintaining and monitoring sensing equipment linked to drilling and safety.
• Calculating the drilled formation’s pore pressure.
• Hydrocarbons released from drilled formations are collected, monitored, and evaluated.
• evaluating the production potential of hydrocarbon-bearing formations
• Keeping track of the drilling parameters.

Mud Logging Equipment

A- Drilled rocks tools

• Sample bags, envelopes, and containers.
• Sieve and Scoops.
• Scientific Microscope.
• Sample trays, cut test dishes, probes, tweezers.
• Electric Oven.
• Ultraviolet lightbox.
•  Testing chemicals in dropping bottles.
• Calcimeter.

B- Drilling fluid sensors

• Mud Pits Level sensor
• Mud Weight (density) & Temperature in and out from the hole.
• Mud conductivity (resistivity) in and out from the hole.
• Mud Pump speed.
• Mud Flow Rate.
• Gas Detectors
• Hydrocarbon Analyzer.

C- Drilling Parameters sensors

• Hook-load.
• Standpipe pressure & Casing pressure.
• Draw work Sensor ( Depth Counter) – (ROP).
• Rotary torque.

D- Other Tools

• Computers
• Printers
• Stationary tools.
• Cleaning tools.
• Safety equipment.

Mud Logging Unit Crew

MUD LOGGING UNIT CAPTAIN

The Unit captain is the senior mud logging engineer on the location. He has primary responsibility for the maintenance, management, and provision of service by the logging unit, its equipment, and personnel to the client.

MUD LOGGER

He is responsible for the maintenance and correct operation of the equipment supplied to provide the service. He is responsible for the collation and presentation of the information monitored in accordance with company standard procedures and customer requirements to ensure a high-quality service.

SAMPLE CATCHER

Wash and screen samples, divide them into correct portions and pack them by sets for the Client, partners, and trade.

The Mud Log

Information gathered by the mud logging crew is first recorded on the datasheet and then plotted onto a mud log form.

Each mudlogger is responsible for plotting the data acquired during his shift.

The mud log must be recorded in a standard format to allow valid correlation from well to well this standard format is called (Mud Log Form)

Resources

Mud logging

Mud Logging Services

The oil and gas life cycle of upstream processing consists of five stages:

Exploration phase

Is about finding oil and gas fields. The main goal is to identify and deliver commercially viable field development opportunities.

The following geological and geophysical (G&G) activities would take place:

• Conduct seismic surveys.
• Process and interpret the seismic data and map the potential reservoir.
• Select exploration well locations.
• Drill and evaluate exploration well data.
• Core analysis to establish porosity and permeability.
• Logging data to determine porosity, water, and hydrocarbon saturation.
• Production test data to determine flow rates and maximum production potential.
• Build a computer model of the reservoir and identify and where possible remove major uncertainties by further data analysis, seismic reprocessing, etc.

Appraisal phase

The objective of Appraisal is to obtain information about the reservoir in order to make a decision whether or not to proceed with the development of the field.

This stage comprises the following activities:

• Reprocessing existing seismic data to obtain enhanced results.
• Drilling of appraisal wells.
• Evaluation of the results from the seismic and appraisal drilling activities.
• Using the information from the seismic and drilling programs to update the computer reservoir simulation models.
• Conduct initial conceptual field development planning and study of these conceptual plans.

Development phase

Now we’ve determined the size of the oil field, the geologists, geophysicists, and reservoir engineers must put their heads together and plan the location for the development wells.

The object, at this stage, is to get the maximum amount of oil out of the ground with the minimum number of wells.

Production phase

Is targeted at bringing the well fluids to the surface and preparing them for use in refinery or processing plants.

 The main activities consist of the following:

• Regulate production and injection to meet approved plans for the quantity and quality of the product.
• Monitor and record all information to manage the reservoir, wells, and facilities.
• Plan and schedule all production and maintenance activities to minimize production operating costs. 

Abandonment phase

The end of the life of the field is when it is no longer economic for the operator to continue production.

The major activities during the decommissioning phase are:

• Plug and abandon wells by putting cement plugs into the well and removing the well-head.
• Ensuring that there is no contamination of the environment from any oil or waste material remaining in the process facilities.
• Restore the site to its original condition.

Written by/ SkillsSer Editors Team

Drilling fluids are fluids that are used during the drilling of subterranean wells. They provide primary well control of subsurface pressures by a combination of density and any additional pressure acting on the fluid column (annular or surface imposed). They are most often circulated down the drill string, out the bit, and back up the annulus to the surface so that drill cuttings are removed from the wellbore.

Functions of Fluids

• To remove the cuttings from the bottom of the hole and carry them to the surface.
• To transmit hydraulic horsepower to the drill bit.
• To cool and lubricate the drill string and bit.
• To exert sufficient hydrostatic pressure to control fluids encountered in formations penetrated.

*To minimize settling of cuttings and weight material in suspension when circulation is temporarily stopped. The mud, however, should have properties that allow the cuttings to settle in the surface system.

• To support and protect the walls of the hole.
• To reduce to a minimum any harm to the formations penetrated.
• To ensure maximum information about the formations penetrated.

Test and Mud Properties

Various properties of the mud are measured as an indication of the performance of the mud in the hole.

This stage comprises the following activities:

Density Or Mud Weight

Density Or Mud Weight affords a measure of the hydrostatic pressure of the mud column.

Viscosity

Viscosity is a measure of the internal resistance of a drilling fluid.

Plastic Viscosity

The Plastic Viscosity depends mainly on the friction between solids and the liquid.

Yield Point

Yield Point is a measure of the attractive forces between active clay particles in the mud under flowing conditions.

Gel Strength

Gel Strength is a measure of the attractive forces of suspended particles in a liquid when that liquid is in a static state.

Filtration

The filtration test is a relative measure of liquid filtered into a permeable formation and of the cake left on the formation.

Sand Content

Sand Content is measured because sand is abrasive to the equipment that comes in contact with the mud and sand may cause trouble by setting in the hole or by increasing the mud weight.

Solids, Oil, And Water Content

Solids, Oil, And Water Content are measured not only as a basis for the control of the oil content of emulsion muds but also as an aid in the control of the performance of the mud.

Chemical Tests

Chemical Tests are made on the mud and filtrate as an aid in the identification of contaminants and in control of mud properties.

Types of Drilling Fluids

Water-Based Drilling Fluids

Oil-Based Muds

a- Invert Oil Mud

b- Relaxed Invert Oil Mud

Additives For Drilling Fluids

• Fresh Water, Low pH
• Brackish Water, Low Ph
• Gyp Treated, Low Ph
• Lime Treated, High Ph
• Fresh Water High Ph
• Low Solids
• Emulsions
• Oil-In-Water.
• Water-In-Oil
• Oil Muds
• Air, Gas, Mist
• Foam