Rigless Interventions in Failed Gravel-Pack Gas Wells Using New Resin Systems

Summary When a gravel-pack completion fails, it usually results in loss of production for the interval until a workover rig is available to recomplete the well. This paper describes two recent successful rigless interventions completed in offshore multizone completed gas wells in the Adriatic Sea. A key factor in the success of these remedial treatments has been the application of two different chemical technologies applied to the proppant while it is being pumped into the well. In the first well, production loss was caused by fines migration (fine silt ≤44 microns) into the 40/60 gravel-pack sand, which completely plugged the screens and gravel. An intervention was performed which included sealing the existing completion and then reperforating the premium screen using wireline guns. The interval was then fractured with a tip screenout design and a through-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 this technical choice. A different problem existed with the second well, which had a frac-pack completion; in this case, a screen failure resulted in formation sand and proppant being produced to the surface. The well was refractured 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 productivity index (PI). In both cases, these treatments have put back into production wells that in the past could not have been restored to production except through recompletion using a workover rig. This paper will describe the treatment design, well operations performed, materials used, and production performance of each well, comparing each aspect with the case of a conventional recompleted well.