Wireline Witnessing
Precision and accuracy of the downhole logging measurements is critical for further decision making. We offer our experience acquired over many years of work in Wireline industry to support preparation, execution and post-job follow up for Wireline operations.
Wireline Logging Witness encompasses a number of responsibilities:
- Coordination of all well-related logging activities – pre-job, during the job, and post-job
- Training of any new service company Logging engineer on client specific requirements
- Interfacing with the Logging engineer, Operations geologist, Well engineer and Drilling Superintendents
- Pre-job, during the job, and post-job reporting of logging objectives and operations
- Participation in and supervision of on-rig wireline logging operations
After the service company is informed of the upcoming job and a logging crew is selected, a wireline witness is also appointed to cover the job. The log witness is sent the wireline logging program and briefed by the operations geologist or well engineer of the operating company.
The logging witness is considered the leader of the logging service project team consisting of the service company logging engineer, his/her crew and the drilling superintendents on the rig. Prior to the job, the initial interactions between the logging witness, drilling superintendents and logging engineer should take place, getting consent on the following points:
- Logging program and objectives
- Tools required and tools available, readiness status
- Toolstring configurations & optimization options
- Risk assessments and potential safety issues, prevention measures
- Preliminary details of the logging plan and timing
- Lessons learned from previous wells
The logging crew have to check all their equipment to ensure all the logging tools are in working condition and no equipment required for the job is missing. The logging engineer must report any tool problems or missing equipment to the wireline witness and the drilling superintendents on the rig. At this point, the logging program might undergo refinement through discussions between the operating company and the service company with the logging witness taking on an advisory role. Logging time estimates, log presentations and pre-job well information sheets are also prepared prior to the job starting. Any discrepancy in the estimated logging time forecast should be highlighted to the drilling superintendent to aid forward planning and logistics. When the job commences, the wireline witness has responsibilities, which include:
- Logging company data acquisition: supervision and quality control
- Data formatting and/or reformatting
- Downhole sample taking supervision: Formation Testing and Coring
- Daily job reporting
- Ongoing job risk assessment
Once the rig down is complete after the job, the wireline witness follows up on:
- Rush and Final Data delivery
- Post-job reports delivery
- Lessons learned and recommendations
- Post-job SQM participation
Wireline Witnessing definitely brings value to operating company and has the following benefits:
- Close follow and control of the operation by subject matter expert
- HSE incident prevention and mitigation
- Process standardization
- Real time data quality verification
- NPT prevention and mitigation
- Thorough documentation and archiving
- SQ and data quality improvement