Abstract
Hydraulic fracturing is the preferred method for enhancing production rates and hydrocarbon recovery, as well as for maximizing the productivity of conventional and unconventional reservoirs. To optimize the effectiveness of the treatment and maintain wellbore integrity, the stimulation process should be designed and executed with both the wellbore configuration and target formations in mind. For wells in which multiple fractures are required, stimulations are normally performed sequentially, from the bottom layer to the top layer; however, open perforations above the target zone (whether fractured or not) can present significant challenges during the stimulation process. For these cases, the preferable solution has been to isolate the perforations using the cement-squeeze technique, but this process is not completely effective because of short penetration. The fragility of the cement slurry under typical stress cycles associated with the fracturing process or the complexity of the process could compromise the existing perforation integrity and the effectiveness of fracturing the lower zone. Alternatively, the well can be recompleted to isolate the zone mechanically, though this involves a rig operation, which, in zoned areas, is not cost-effective.
One effective method to isolate existing perforations and help ensure deeper penetration of the isolation system without pulling out of the completion is squeezing a resin-based system with sufficient plasticity to maintain the isolation integrity under normal stress cycles. This paper documents the first application of resin blends to isolate existing perforations for the fracture stimulation of deeper prospective horizons. This isolation and stimulation process follows these steps: (1) the resin blend is squeezed into the wellbore using coiled tubing (CT); (2) the remaining resin blend is cleaned up using CT and a pressure test is performed; (3) the deeper horizon is perforated; (4) a minifrac and temperature survey are performed to evaluate existing perforation isolation; and (5) the fracture stimulation and production evaluation are performed.
