Planning and supervision is crucial in cementing operations. This article describes the key responsibilities for the Drilling Supervisor, Cementing Engineer, Mud Engineer and Drilling Contractor.
Operations Engineer
- ensure cement, mixwater and additive samples are sent in time to the service company for testing
- check that the cementation proposal meets the objectives of planned cementing operation
- ensure cement, additive and mixwater samples are despatched correctly marked and packaged
- check log downhole temperature and compare with slurry design temperature.
- witness and check quality control of calliper logs
- check cementation proposal and reports
- discuss with cementing contractor about new equipment/chemicals
Drilling Supervisor
- overall responsibility for the conduct of the cementation
- compare job calculations with those of the Cementer
- supervise the Cementers and Drilling Contractor in the performance of their duties
- inform the Mud Loggers, Mud Engineer and Driller:
of the volume of each type of mixwater to be used for both lead and tail cement jobs
from which mud pit each type of mixwater will be drawn
of the expected gain, per barrel of mixwater blended with cement, for both lead and tail slurries
of the expected total volume of returns during the cement job and the expected overall increase in pit volume
- co-ordinate the execution of the cement job
- ensure that all relevant personnel are issued with a detailed programme of the cement job, highlighting individual responsibilities (the detailed programme must include volumes, pressures and pump rates for the cementing and displacing operations)
- ensure that all relevant personnel are issued with contingency plans (flowcharts) to assist in rapid decision making should something go wrong
- witness:
no changes are made to the agreed programme without the prior approval of the Drilling Manager
the landing and hanging off of the casing, including the pressure testing of hanger seals if applicable
pressure testing of the surface lines before the job
the circulation test
the placing of the cement plugs in the cementing head
the preparation of the cement slurry and spacers (no deviation from the recipe shall be permitted)
the pumping of spacers and cement slurry
- count the number of tanks and fractions of tanks for the calculation of the volume of slurry pumped
- use chart recorders during cementation to record as many relevant parameters as possible, such as:
pumping pressures
times of the various actions
cement slurry gradients
losses
- ensure equipment is in a state of readiness
- collect samples of mixwater, cement and additives during the cement job
- confirm stock levels of cement and additives
- supervise preparation of spacers, mixwater cement slurries and additives.
- ensure dry cement is fluffed as per Contractor recommended procedure
- prepare all cementation reports.
- complete checklists prior to commencement of cement job
- arrange loading and backloading equipment
- confirm receipt of the cement test report recipe for the cement and spacer from the Operations Engineer.
- ensure that all checks are performed.
- Two days before the cementation is started, he will collect the checklists and address any problems. Other personnel listed shall carry out the checks, sign off the checklists and return them. A copy of the checklists shall be faxed to the office.
Drilling Contractor
- operate and maintain the bulk air supply and mixing systems
- provide personnel for loading and backloading of supplies and equipment
- assist with sampling prior to, and during, the cement job
- assist with measuring the gradient of the slurries pumped
- complete the minimum checks and procedures detailed in the checklists and pass completed checklist to the Drilling Supervisor prior to commencement of the cement job
- provide lines for cement and water from supply boat
- hook up cement/water lines as needed
Cementer
- maintain and operate the cement unit and all associated equipment on the rig to the highest standards of reliability
- ensure that the unit is functioning efficiently and has valid certification
- record and maintain quality control of stock levels of cement/additives and physically check all stocks on a weekly basis and prior to any cementing operation
- ensure that:
liquid additives are checked by use of a hydrometer
adequate spare parts and consumables to support the operation are maintained
all materials used and delivered are recorded in a log book
- carry out individual cement calculations and compare these with the calculations of the Drilling Supervisor
- perform the cement job as per the programme specified by the company, including the use of data recording devices
- complete the minimum checks and procedures detailed in the checklists and pass completed checklist to the Drilling Supervisor prior to commencement of the cement job
- advise drilling supervisor of any changes in cementing program
- send the test results to the Operations Engineer and the Drilling Supervisor for verification at least three days before the job is scheduled.
- confirm the laboratory bench tests at the well site.
- distribute the checklists, which clearly define the responsibilities of personnel involved in the execution of the cementation.
Mud Engineer
- check the mixwater for contamination and measure salinity
- ensure mud is in good condition (no foam)
- ensure the mud has been pre-treated to minimise cement contamination problems
- ensure that there is sufficient volume of mud available on surface prior to commencement of the cementation
- ensure sufficient space is available for spacer or additives to be stored
- monitor pit volumes throughout the cementation
- measure cement gradient as required
- check fluid returns for presence of cement, spacer or drilling fluid.
Mud Logger
- monitor pit volumes throughout the cementation, independently of the Mud Engineer
- report to Drilling Supervisor immediately in case of discrepancies during displacement.