Publications

Perforating long intervals on horizontal wells requires a dedicated understanding of the reservoir properties and diligent perforation design. Medco LLC (Oman) decided to perforate three reservoir intervals (133 m) of a highly deviated well with the optimum perforation charges for maximized oil productivity while minimizing the number of runs required. An underbalanced perforating strategy was embraced to better clean the perforation tunnels posterior to detonation and hence to increase the well to reservoir communication quality. Perforating design was performed by Schlumberger proprietary perforation analysis software to compare the various gun systems and the resulting well productivities. Perforations were conveyed on tubing and the gun shock models were created to ensure flawless operations that might be jeopardized by the shocks resulting from the perforating job. As a result, the perforation operation was successfully performed without any operational and HSE issues. The actual production was in line with the expectations as predicted by the perforation analysis software. Production from the well was actually better than the neighboring wells in the same region. Medco’s choice on the novel perforation charge selection proved to be a fulfilling and smart decision. The predicted production rates were matched by actual oil production proving the certainty of the input parameters for perforation and productivity modeling such as reservoir permeability, porosity and the fluid characteristics. The incremental cost on the perforation gun system has imperatively paid off by the gained production of oil. In this paper we discuss the lessons learned from the operational stand point as well as the well to reservoir communication efficiencies as predicted and actually occurred. The rock based perforation penetration and a productivity model is also discussed in detail.