Raudhatain-Mauddud, a super-giant depletion oil reservoir in North Kuwait, consists primarily of two areas: the crest of the reservoir with good rock/fluid quality and the flank area with poor rock/fluid quality. In some areas of the reservoir, however, especially in the flanks, the rock attributes are not fully mapped. The typical perforation that is being followed while completing the wells in the flank area of the reservoir uses either wireline-conveyed perforation or the underbalance firing TCP shoot and pull technique. The wells are then often acid stimulated to improve the injectivity/productivity profile of the injector/producer wells, respectively.
A new approach involving the propellant-assisted perforation technique was applied in five wells in the flank area of the Raudhatain-Mauddud reservoir. The results show a significant improvement of injectivity/productivity. Because this technique was being used for the first time in this reservoir, and probably for the first time in Kuwait, several variations were tested to perforate these wells in the flank area of the Raudhatain-Mauddud reservoir.
The propellant-assisted perforation was initially performed in an underbalanced environment; results of the well post-workover were compared with simulation runs. In the second trial, these guns were fired in an overbalanced condition with an extra overbalance added by pumps over the hydrostatic, and the results after the workover of the well were compared with the simulation trials. Extending the encouraging results obtained in these trials, an innovative approach was tried when the normally used post-perforation treatment acid was used as an incompressible spearhead against the perforations. The results of this approach showed that this technique can provide an effective stimulation method across the perforated interval and eliminates the need of separate acid stimulation run, reducing rig time and costs. This paper presents the comparisons between the productivity/injectivity improvements for these wells in the flank area of the Raudhatain-Mauddud reservoir using these different approaches of the propellant-assisted perforation technique in different conditions.