When a Gravel Pack Completion fails it usually results in the loss of production from the interval until a workover rig is available to re-complete the well. This paper describes two recent successful rigless interventions completed in offshore multi zone completed gas wells in the Adriatic Sea. A key factor in the successes of these remedial treatments has been application of two different chemical technologies applied to the proppant whilst it is being pumped into the well.
In the first well, production loss was caused by fines migration (fine silt ≤ 44 micron) into the 40/60 gravel pack sand, which completely plugged the screens and gravel. An intervention was performed which included sealing the existing completion, followed by re-perforating the premium screen using wire line guns. The interval was then fractured with a tip screen out design and a thru tubing screen was placed across the perforated screen. Critical to this treatment was the use of a surface modifying agent to prevent fines migration and plugging of the gravel pack. Production results have confirmed the correctness of the technical choice.
A different problem existed on the second well, which had a fracpac completion; in this case a screen failure resulted in formation sand and proppant being produced to the surface. The well was re-fractured through the hole in the screen and a newly developed resin was applied to the proppant to lock the proppant into place and thus repair the damaged screen without restricting the flow area with a secondary inner string. Unlike conventional resin coated proppant at low temperatures this new type of resin does not require confinement pressure and or the use of chemical flushes to cause the resin to set. Since the intervention, the well has been producing sand free at very close to the original PI.
In both cases these treatments have put back in production wells that in the past the only alternative was to recomplete using a workover rig. This paper will describe the treatment design, well operations performed, materials used and production performance of each well comparing this to a conventional recompleted well.