Case Study

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Sand Management for High Rate Gas Wells - Lunskoye Field

 

Background

• During FEED of Big Bore Gas wells (350 mmscf/d), BoD completion see as risky for sustainable gas delivery to LNG trains.

 

Technical Challenge

• $22 billion LNG & oil (Sakhalin II) development reliant on 6 Lunskoye gas wells producing > 300 mmscf/d/well,

• Sand production predicted from day 1,

• BoD completion was slotted liner/barefoot, with a risk of well sanding up, and erosion of facilities,

• Wells sand up would lead to >3 month delay/ well,

• Every day off plateau production and missing LNG cargoes would cost many $millions/day,

• Arctic conditions & remote location: Sakhalin Island,

• Old Exploration wells – no new data.

 

Solutions

• Completion re-selection considering the onset of sand production for different layers and the calculations of how much sand would be expected (Sand Quantification).

• The review of all sand and sand screen sand control options as well as well re-design, considering all technical, financial and HSE aspects. The preferred completion was a selectively perforated completion,

• Back-up completions identified were Expandable Sand Screen followed by Open Hole Gravel Pack.

• Improvements were introduced to estimate the volumes of sand production and sand quantification and to improve Inflow model for detailed selectively perforated completions.

• Sand management plan formulated based on sand quantification, erosional considerations, sand handling, and sand and flow line monitoring.

• Real-Time completion program developed for gun design, to customise the selective perforation design for each individual well, based on the well trajectory and the formations encountered (based on LWD),. 

• Modified well plans put in place for second phase of well drilling.

• Partner buy-in through regular meetings and updates as the modified completion designs were refined.

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