5.Mud Logging Definition

- 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.

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.

A- The essential role that the unit plays on board, is the collection of the rock cuttings which is geologically described, examined for any oil shows and then packed according to the exploration company requirements.

B- The mud logging unit is responsible for the hydrocarbon gas monitoring while drilling. These gases are detected as a total value then are analyzed to their components.

C- The mud logging unit is responsible for the detection of the Hydrogen sulfide (H2S) gas while drilling which is very dangerous if it is not detected in the very early stage.

D- The mud logging unit is responsible for the monitoring of the drill fluid volume second by second and to immediately inform the personnel in charge about any change in that volume (Loss/Gain).

E- The mud logging unit is responsible for the generation of mud logs and graphs during the drilling of the well, acquisition of the data and producing a final well report.

F- The mud logging unit is responsible for the monitoring of the drilling parameters such as : WOB, RPM, TRQ. ...etc.,. And to inform the personnel in charge about any anomalies or figures that could be out of the set ranges.

G- The mud logging unit is responsible for confirming with the driller about any drilling breaks.

H- The mud logging unit is responsible for monitoring the trips and updating a trip sheet at a five-stand basis. This trip monitoring sheet includes the calculated/observed hole fill-up or string displacement along with remarks on string overpull, tight spots and running speed.

I- The mud logging unit extends its service to the detection and evaluation of the formation pressure, the hydraulics optimization and the well control.

The mud logging unit is considered the information center of the rig site as the unit participates in the monitoring of each and very rig operation.

28. 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.

A- Mud Logging Off-line service features

The off line mudlogging unit includes a number of separate panels. Each panel works independently and is responsible for measuring a definite parameter. There is no communication between these panels. No automatic calculations can be done and no data storage. All panel calibrations are done manually.

B- Mud Logging On-line service features

1-Minimum human interference:

Operation, calibration and data processing starts at the sensing point and goes all the way until the final output is produced. The result is:

- Random errors minimized, i.e best accuracy.

- More time for interpretation.

- More time for monitoring.

2- Fully computerized service with powerful software:

- High speed data processing (possible data transmission)

- Better presentation of data.

- On time decision making.

3- Best possible equipment design in the industry:

- Maximum possible accuracy.

- Minimum systematic errors.

- Minimum down time.

4- Intrinsic safety:

- Safety environment

- Safety equipment

- Efficient warning system

MUD LOGGING ON-LINE UNIT EQUIPMENT

1. Geological equipment -Microscope - Fluoroscope - Auto Calcimetry Kit - shale Density kit

2. Remote pump stroke counters

3. Multi-channel, high resolution chart recorders

4. Flame ionization hydrocarbon gas detector (FID)

5. Flame ionization gas chromatograph (C1 - C5)

6. Drill monitor panel

7. Depth - WOB - RPM - Torque

8. Pressure detection system standpipe pressure (SPP), Casing pressure

9. Pit volume totalizer

10. Mud weight (in and out)

11. CRT information system

12. Mud temperature (in and out)

13. Mud resistivity (in and out)

14. Mud conductivity (in and out)

15. H₂S gas detector

16. CO₂ gas detector

17. PC computers (on-line & off-line)

18. Mud flow sensors (in and out)

19. Central air-conditioning units

20. Unit voltage regulator

21. Uninterruptable power supply (UPS)

General features of Sperry- Sun On-line Mud Logging unit LS-2000:

• Continuous real-time monitoring.

• All equipment measured data is fed directly to the computer.

• LS 2000 is multi-tasking real-time data acquisition and monitoring system.

• Automatic determination of the operation status.

• The unit is constructed to US Coat Guard safety regulations .

• Skid mounted

• Pressurized insulated shell.

• Exploration proof junction boxes.

• Intrinsic safety through the use of safety barriers.

• Non volatile data memory buffer which enable to retain all the data the event of power failure or gas hazard shut down.

• Open system structure, this gives the system flexibility to upgrade when new multibus compatible boards become available.

• On-line calculation of appropriate values, LS 2000 system automatically perform a variety of calculations on the parameters monitored created records for data storage and produces reports displaying the information.

• LS 2000 software can construct a very strong and logic alarm net to cover up to 30 parameters, which is very important for rig safety and lead to minimizing the down time.

• Ls 2000 sensors are designed to provide high accuracy and to minimize the down time. All the sensors are calibrated and controlled by the computer.