Optimizing Fracture Control in Thin Multilayer Carbonate Reservoirs with Surgifrac Stimulation

Summary The complex depositional and diagenetic environments experienced by the carbonates in the region result in highly heterogeneous reservoirs often translating to equally variable reservoir thicknesses and properties in their intra-layers. Acid fracturation is a widely deployed technique to increase the productivity and oil recovery of carbonate oil reservoirs by reduction of formation damage (skin) and enhancement of the reservoir-wellbore interface and interconnectivity. However, as carbonates often have a pre-existing natural fracture network, the consistency of acid fluid treatment distribution, control of fracture propagation and the areal extent of enhanced connectivity are often key uncertainties that are challenging to constrain. Thus, alternatives stimulation techniques are of interest where there is a significant risk of connection to water-bearing zones. Following a market research exercise for alternative stimulation techniques, Halliburton’s Surgifrac technology was selected as the most suitable stimulation technique for a pilot on the target reservoir. The pilot yielded positive results, increasing the productivity index (P.I) of the treated interval by 2.5 times. Subsequent well testing showed no negative impact on the BSW (%) of the target zone, effectively mitigating the major risk associated with acid fracture operations.