Schlumberger

Case Study: Efficient Perforating Saving 2+ Days and up to USD 300,000 in Deep Arabian Gulf Reservoirs

Increased gun size and length, added selectivity, and tension modeling with stronger cables improve perforation performance for ADMA-OPCO

Challenge: Improve efficiency and perforation performance in wireline perforating 1,200-ft intervals in deep, deviated offshore wells that require a full wellhead pressure control system.

Solution: Work closely with ADMA-OPCO personnel to

  • increase gun size to use deeper penetrating PowerJet Omega 3506 charges for performance
  • reduce the number of runs with longer gun systems and selective switches
  • improve safety with larger-diameter cable employing an electric release system plus a tension model for each perforation run.

Result: Reduced rig time by more than 2 days on some wells and saved USD 50,000 to USD 300,000 per well while delivering better well performance

Challenging perforating conditions

Abu Dhabi Marine Operating Company (ADMA-OPCO) wanted to improve both the efficiency of wireline perforating operations and the subsequent performance of the perforations in a deep carbonate reservoir with H2S gas in the Arabian Gulf. Conditions for perforating are challenging: deviated offshore wells accessing a massive complex of limestone, dolomite, and anhydrite with a large range of permeability and porosity.

Typically 300- to 400-ft perforated sections are completed over a 1,200-ft interval at balanced or underbalanced conditions, requiring use of a full wellhead pressure control system. It takes 10 to 15 runs to completely perforate a well, with each run requiring 8 or 9 h.

Improving gun capabilities and operational safety

To improve perforation performance, PowerJet Omega 3506 charges were chosen to shoot deeper into the reservoir. The gun size was increased to 3½ in to accommodate the premium charges, and selective switches were added to enable shooting more gun sections on a single run. To further lower the number of runs, the cable size was increased to 0.32 in, which raised the maximum safe working strength from the previous 2,890 lbf to 5,000 lbf and allowed heavy 60-ft gun lengths per run.

Improved safety was also a consideration. The weakpoint in the logging cable attachment to the tools was replaced with an electric release system to support the increased weight of the longer, larger gun strings. Tension profile modeling was also conducted for each perforation run.

Saving time and raising well performance

Running longer gun strings with selective switches resulted in significant rig time reductions of more than 2 d on some of the wells, with USD 50,000 to USD 300,000 saved per well. The PowerJet Omega deep penetrating charges are delivering markedly better well performance.


Download: Efficient Perforating Saving 2+ Days and up to USD 300,000 in Deep Arabian Gulf Reservoirs (0.33 MB PDF)

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