Client: Major oil company
Topic: HSE QC, HSE audit, survey QC for OBC seismic survey

Situation

• The provision of HSE QC and survey QC
• A very large 3D ocean bottom cable (OBC) survey offshore Qatar
• Dual sensors, an orthogonal spread
• Longest lines over 20km in length

Challenges

• Shallow and variable water depths
• Multiple vessels
• Sand banks, coral heads, wrecks and other subsurface obstructions
• Fishing vessels
• Significant bad weather
• Close proximity of a shipping lane
• Night time operations
  
  

Actions

• Full quality control of the contractor’s positioning data
• Independent check of all start-up verification procedures, acoustic positioning reports, preliminary and final SPS data prior to final acceptance as deliverables
• Frequent field visits to operational vessels to check and monitor the quality of work and the status of the equipment, SOP compliance, monitoring of sound velocity tests etc
• Operations were reviewed and audited 
• HSE monitoring of trouble shooting vessels, multi-purpose vessels, gun boats, supply boats, fast transfer boats, a chase boat, a scouting vessel, the sister vessel and the main mother vessel
• Large number of daily toolbox meetings focussing on particular safety issues required for such a complex operation
  
  

Results

Safe acquisition of accurate positioning data in an OBC operation involving more than 20 survey vessels and very long receiver lines, this in addition to operations being carried out during night time hours