In the North Kuwait (NK) Raudhatain field (RA), the Mauddud formation (MA) has been proven to have the potential for hydrocarbons for a decade due to the good petrophysics properties and reservoir thickness of 312 ft. Most producers faced significant reservoir pressure depletion due to poor reservoir support mechanism generally in the field. On the other hand, the northern area of the reservoir has poor reservoir quality, which necessitates aggressive stimulation intervention to unlock the oil potential. Thus, an innovative solution is required to overcome these challenges in this well. The application used in the well was a combination of open hole multi-stage completion and suitable acid fracturing design in 2313 ft of lateral. The open-hole Multi-Stage Fracturing (MSF) completion system consists of a toe sleeve, ball drop sleeves, and high-performance open-hole packers to isolate between different stages. The well was spaced out in average 231 ft per stage, resulting in 10 frac stages total. Additionally, the toe initiator placed in the first stage is opened hydraulically, whereas the remaining stage ports are opened by using a dissolvable coated ball. The fracturing design consists of a combination of low-pH crosslinker gel, 15% hydrochloric acid (HCL) as the main Acid, and visco-elsastic surfactant (VES) as the diverter stage. The dosage used was 320 gal/ft, 210 gals/ft, and 110 gal/ft, respectively, and flushed with 110 gals/ft of oil-based solvent to clean out the residuals.
This application in the Raudhatain field of the Northern Kuwait oil fields yielded a uniform acid fracturing stimulation for all 10 stages of the Mauddud formation; the candidate was well completed and stimulated successfully. In the trial well, 9 dissolvable ball drop frac ports with hydraulic toe initiator were deployed across 10 stages per the requirements. No indication of leaks and unexpected pressure drops were shown throughout the operations, and zonal isolation was maintained throughout all stages. This MSF completions design created a conductive fracture length while confined within the Mauddud formation that provided a successful open hole ball drop acid stimulation along with more efficient fracturing operations by reducing time, resources, and emissions. Additionally, This application resulted in 6 folds of increase (FOI) compared to similar offset wells.
The qualification and implementation of the 10K open-hole MSF completion system was done through a collaborative approach within various entities, and the project scope & review of the solution were extensively discussed with the involved parties who were engaged throughout the project to ensure the final product met expectations. Mauddud is a challenging reservoir to produce. This effective methodology enables engineers to screen similar cases where multi-stage acid fracturing could become a treatment to restore production and encourages the company to develop this reservoir and other equally challenging.
