Achieve deep, clean penetration in perforating new 9 5/8-in wells'

For producing from the Paraiso and Huachito fields in Ecuador, ENAP–SIPEC wanted to perforate a 9 5/8-in production casing, connecting to the virgin rock with clean perforation tunnels and avoiding having to kill the well. ENAP–SIPEC had drilled the wells larger than the usual 7-in casing to provide room for larger perforating guns that would be more likely to achieve the deepest and cleanest penetration. The completion design required a no-kill technique to eliminate the use of kill fluids, minimize the risk of fluids invasion into the reservoir, and mitigate the costs for special fluids to control losses.

Connect to the virgin rock using a customized solution'

Reservoir penetration was optimized using the PowerJet Nova charges with the PURE system and the 9 5/8-in MAXR anchor. Designed using an extensive database from perforations in real rock targets at reservoir conditions, PowerJet Nova charges deliver the industry's deepest penetration in stressed-rock formations for optimized perforation and production. Schlumberger engineers use SPAN Rock stressed-rock perforating analysis to select the best PowerJet Nova charges for each deployment.

Whereas conventional perforating relies on a large static underbalance that is established before the perforating guns fire, the PURE perforating system maximizes the dynamic underbalance immediately after the perforation cavity is created, removing perforation debris to the gun chambers for the cleanest possible perforations and for efficient communication between the reservoir and the wellbore. Anchoring the PURE system with the MAXR anchor provides automatic drop-off at detonation, generating enough force to drop the entire toolstring to the well rathole and provide unimpeded access to the pay zone for future intervention or workover.

Obtained a nearly 300% increase over the estimated production

This first-time use in South America by ENAP–SIPEC of a custom-designed perforating solution comprising PowerJet Nova charges, the PURE system, and MAXR anchor exceeded the production estimate by 278%, delivering 1,700 bbl/d compared with the original estimate of 450 bbl/d. A buildup test was performed at the end of the operation to evaluate the perforating performance and well stimulation.

ENAP–SIPEC reported a negative skin of –3.8 indicating enhanced productivity due to stimulation. A second well also showed outstanding results, flowing directly to the processing facility with no artificial lift necessary for 17 days. In addition to negative skin for higher productivity and savings in completion fluids, perforating with PowerJet Nova charges and the PURE system also reduced the perforating shock experienced by the ESP.