Mud Logging - Parameters Monitoring

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All the parameters specified in the contract scope of services shall be recorded against time and depth and continuously monitored. The following table lists the recording frequency and standard units to be used for all mud logging parameters.

Parameters

Parameter

Recording Frequency

Units

Active pit volume

Continuous - Alarmed

bbls

Reserve pit volumes & Trip tanks

Continuous

bbls

Mud flow in

Continuous

gpm

Mud flow out

Continuous - Alarmed

gpm

Loss or Gain

Continuous - Alarmed

bbls

Mud weight in

Continuous

ppg

Mud weight out

Continuous

ppg

TVD

Continuous

feet

Inclination

Continuous

degrees

Azimuth

Continuous

degrees

Total gas (as percentage methane in air)

Continuous - Alarmed

%

Gas Chromatography (C1 - C5)

Minimum 5 minute cycle

ppm

H2S and CO2

Continuous - Alarmed

ppm

Mud temperature in and out

Continuous

0C

Hookload

Continuous

lbs

Weight on bit

Continuous

lbs

Time on bit

Continuous

hours

Bit depth

Every 3 feet

feet

Rotary speed

Continuous

rpm

Total bit revolutions

Continuous

revolutions

Standpipe pressure

Continuous

psi

Rotary torque

Continuous - Alarmed

ft lbs

Rate of penetration

Every 5 ft

ft/hr

Average rate of penetration

Every 5 ft

ft/hr

Pump speed (strokes)

Continuous

stroke/minute

Circulating hours

Continuous

hours

Standpipe pressure

Continuous

psi

Theoretical hookload

Every Stand - During Tripping

lbs

Overpull - maximum value

Every Stand - During Tripping

lbs

Lag time

Continuous

minutes

Lag depth

Continuous

ft

Calcimetry

As Required

 

Fluorescence

As Required

 

Background gas

Continuous

%

Trip gas

As Required

%

Off bottom depth

As Required

ft

Bit on bottom

Sliding

Rotating

Hrs

Hrs

Drilled interval

Sliding

Rotating

ft

ft

Immediate Notification Requirements

The mud logging unit personnel shall inform the Driller immediately, followed by the Drilling Supervisor of any of the following:

  • Potential well control problems or drilling hazards.
  • All pit alarms and trend changes in the trip tank (other than planned maintenance and/or volume movements between pits in the mud system).
  • All gas alarms.
  • Any significant divergence in mud density of the drilling fluid entering and leaving the well.
  • Any increase or decrease from the torque baseline.
  • An increasing or decreasing trend in standpipe pressure.

Detailed Monitoring Procedures

It is imperative that the mud logging data are cross checked with the rig sensors and discrepancies resolved on a regular basis. The presence of a Mud Logging unit on the rig must not be allowed to reduce the Drilling Contractors responsibilities for the monitoring of parameters. The Drilling Supervisor and Well Site Geologist shall promote a good working relationship between the Mud Logging and Drilling Crews.

The Drilling Supervisor shall ensure that the following points are followed for monitoring and recording services.

  • A calibration check shall be performed daily during all times that the unit is operational. The calibration check shall compare the sensor reading in the unit to the actual measured value. A note of all calibration checks shall be included in the unit diary which shall be checked by the Drilling Supervisor.
  • The total gas detector shall be continuously monitored on a strip chart recorder and via a computer controlled audible alarm. Alarm limits shall be set such that a 10  increase in gas level activates the alarm. The chart recorder output shall be clearly annotated with the depths of all peaks and time. Connection gases and trip gases shall be clearly annotated.
  • The trip tank gas line shall be blown out hourly at a suitable time during a connection. The position of the gas trap in the mud returns shall be checked twice per hour when circulating.
  • The total gas detector shall be calibrated daily by the injection of a fixed amount of known gas concentration. The date, time and calibration value shall be recorded in the unit log book.
  • The gas chromatograph shall cycle continuously on a strip chart recorder. Hydrocarbons in the C1 to C5 range shall be recorded.
  • The chromatograph shall be calibrated daily by injection of a sample of known proportions C1 - C5 and converting chart divisions to ppm.
  • The rate of penetration calibration shall be checked twice per day from the Driller’s pipe tally. Depth measurements must be accurate to the nearest 6in.
  • An alarm should be set on the active pit at all times. Calibrations shall be checked weekly, and if routine pit dipping indicates a discrepancy. In addition the Drilling Supervisor shall perform a pit drill at least weekly on the Mud Logging Contractor active pit sensor. Reaction time for the Mud Logging Contractor to react and alert the rig floor and pit room shall be recorded in the unit logbook.
  • The mud density out sensor shall be cleaned at least every trip. Calibration shall be continually checked by reference to the Derrickman’s 30 minute mud density check.
  • An automatic high/low alarm shall be set on the torque value for each operation. The torque values shall be verified with the rig floor sensor hourly.
  • Initial calibration of the standpipe pressure shall be carried out with a dead weight tester at the beginning of every well. The pressure values shall be verified with the rig floor sensor hourly.
  • Hydrogen sulphide sensors shall be placed at the bell nipple, possum belly, pit room and rig floor areas. These sensors shall be calibrated daily. These sensors shall be tested monthly with small amounts of H2S. The control room and neighbouring rigs/stations must be informed prior to carrying out this operation.

Mud Logging - Pore Pressure Prediction

When specified, the data listed below shall be continuously calculated by the Mud Logging Contractor.

Parameter

Minimum Frequency

Units

Estimated pore pressure gradient

Every 10 ft

psi/ft

Static and dynamic overbalance

Every 10 ft

psi

Fracture gradient

Every 10 ft

psi/ft

Over burden gradient

Every 10 ft

psi/ft

Mud Logging - Report/Logs

Mud logging crew shall ensure that the logging report is submitted at 0600hrs and 1600hrs for the wellsite geologist. A copy of the logging report has to be forwarded to the Drilling Supervisor also.

The mudlog will be updated as frequently as possible to maintain the most up to date information on the well. At zones of interest or at section T.D digital copies of the mudlogging report has to be forwarded to the office.

 

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