Schlumberger

Case Study: eFire Technology Enables Multizone Production from an Unconsolidated Reservoir

Firing heads make it commercially feasible to perforate and produce from three widely separated zones in a sandscreen completion

Challenge: Perforate a multizone well, protect the sandscreen completion, and optimize production where standard perforating technology was expected to be too costly and too risky.

Solution: Perforate each zone individually using eFire electronic firing head systems and high-density PowerJet Omega deep penetrating perforating shaped charges to protect the sandscreen completion and ensure high productivity.

Result: Reduced perforating costs by 50% compared with standard technology using a single firing head and blank guns; achieved commingled production of more than 1,000 bbl/d— 10% higher than expected—without endangering the integrity of the sand screen.

Standard perforation technology was not cost effective or productive

An operator’s production technologists designed a sand control completion for commingled production from three zones in a massive unconsolidated formation, but it would have been impossible to perforate this particular well cost effectively using standard technology.

The distance between zone A and zone B was 915 ft [279 m], and the distance between zone B and zone C totaled 416 ft [127 m]; using a single hydraulic firing head would have meant wasting more than 1,300 ft [400 m] of blank guns to transmit detonation from zone to zone.

To prevent irreparable damage to the sandscreen jackets, high sand velocities would have had to be avoided. With standard shot density, the velocity of the sand-fluid mixture flowing from each perforation tunnel would have had to be controlled by reducing the production rate.

eFire firing heads and PowerJet Omega charges addressed all challenges

To protect the completion and optimize well production, each zone was perforated individually using eFire electronic firing head systems and high-density PowerJet Omega 7027 charges. Three pairs of firing heads were run with tubing-conveyed perforating guns discharging 27 shots per foot.

Standard hydraulic firing heads were ruled out because it would have been necessary to pump nitrogen into the string until detonation pressure was achieved. The operating window of the shear pins of standard firing heads would have been limited by the level of applied pressure the casing was able to withstand.

To avoid the waste of running blank guns between the perforating guns, three gun strings were connected with drillpipe. Each string, therefore, required its own firing head, each detonated with a small nitrogen charge.

Rather than lower the sand-fluid mixture velocity by reducing the flow of production, the total area open to flow was increased. More holes were shot in the casing to lower the velocity of the fluid flowing through each single hole.

Perforating costs were slashed and production was optimized

Using eFire electronic firing head systems instead of standard hydraulic firing heads lowered costs and simplified operations by eliminating the need for hydraulic pumps and nitrogen tanks. The ultrahigh shot density of PowerJet Omega 7027 charges allowed optimized flow while minimizing erosion of the sand screens.

The operator was able to reduce perforating costs by 50% by not having to rely on standard technology using a single firing head and blank guns. Additionally, optimized commingled production of more than 1,000 bbl/d was achieved without endangering the integrity of the sand screen.


Download: eFire Technology Enables Multizone Production from an Unconsolidated Reservoir (0.52 MB PDF)

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Multizone Production with eFire Firing Heads

eFire firing heads and PowerJet Omega chargesPlot tracking the firing-command pressure sequence and the reservoir response.eFire firing heads detonated with nitrogen
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