MUD LOGGING
Mud logging is a service that qualitatively and quantitatively obtains data from, and makes observations of, drilled rocks, drilling fluids and drilling parameters in order to formulate and display concepts of the optional, in situ characteristics of formations rocks with the primary goal of delineating hydrocarbon “shows” worthy of testing.
The mud logging unit is the information center on the rig site to serve both exploration and drilling.
Mud logging theory
The mud logging theory is based on the mud cycle principal. The mud is sucked from the pits (Active Pit) and pumped via the drilling string down to the hole bottom. The mud is then bumped against gravity through the annulus up to the shakers. The time necessary to get the drilled samples to the surface is exactly the time required to pump the mud volume through this passage. This is calculated and is known as Lag time or lag strokes.The calculation and practical application of the lag is of primary importance in mud logging and relates to the all data that the mud transmits to the surface.The mud actually carries the information that we require from the bit depth to the surface and the time that the mud takes to get from the bit to surface is the basic calculation made. The factors that affect the time or lag of the mud are the flow rate of the mud, the configuration of the well; the sizes and depths of the different hole sections and the drill string sections’ dimensions.
General Purposes
• Optimized drilling efficiency.
• Comprehensive formation evaluation.
• Improved well site safety.
Role played by Mud Logging Unit
The mud unit is located very close to the rig floor. A number of cables extends from the unit to a number of sensors installed at different locations on the drilling rig. These sensors are used to measure many important variables or parameters of the rig operations.
Types of mud logging units
Mud logging units can be classified into two main categories depending on the method of data acquisition and processing:
- Off-line mud logging units
- On-line mud logging units
Mud logger basic function
The Mud logging Engineer 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.
