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Downhole Instrumentation Cable: Encapsulated or Bare? When Does it Matter?

July 16, 2014 at 9:23 PM

Permanent Downhole Gauge Technology for Cemented-in Deployments

Written by: Jeff A Scott

Our company manufacturer’s downhole instrumentation sensors. Cementing the pressure sensors in behind the casing is becoming increasingly more common and accounts for a large percentage of our work.

A controversial topic seems to be whether to use an encapsulated cable or a bare cable?

Encapsulation

Permanent Downhole Gauge Technology Cemented in Downhole Sensors

Advocates of encapsulation point out that the plastic jacket overtop the steel cable provides acts as a bumper and improves survivability of the cable during the deployment of the system.

Bare Cable

Permanent Downhole Gauge Technology Cemented in Downhole Sensors

Some of our customers prefer that bare cables be installed, citing that they are worried about channelling or bond issues in the cement.

Permanent Downhole Gauge Technology Cemented in Downhole Sensors

Tell us your opinion!

Does anyone have a right answer? I guess it could depend on the completion?



Tags: downhole instrumentation downhole digital data Oil and Gas Production Downhole Pressure Tools Encapsulated Cable Bare Cable Calgary oil and gas
Category: Technology

Leave your comments!

Posted by Bruce on
Permanent downhole gauge cable installed in an open hole environment where cement integrity is important throughout the wellbore has the best success rate of reaching desired depth when encapsulated, especially in deviated or horizontal trajectories. There is a risk of creating a cement micro-annulus whether encapsulated or bare since the shape of the cable and the method of placing cement all have something to do with the success of all desired parameters. Ruggedized encapsulation could be chosen such that cement adheres more evenly. The tendency of cement on some typical encapsulations is to bead rather than adhere since the main encapsulation construction design intention is not considering the cement environment as the main criteria.

Bare line is round and the risk of micro-annulus is greater due to that shape.

Any oilfield wellbore will normally be concerned about zonal isolation and cement is the most commonly used medium to achieve that. It has been show by wireline logs that micro annulus can appear.

This short information causes me to vote Ruggedized Encapsulated if zonal isolation is a concern.
Posted by John Roberts on
We regularly cement in encapsulated cables in SAG-D observation wells with no issues.
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Downhole Instrumentation Cable: Encapsulated or Bare? When Does it Matter?

July 16, 2014 at 9:23 PM



Tags: downhole instrumentation downhole digital data Oil and Gas Production Downhole Pressure Tools Encapsulated Cable Bare Cable Calgary oil and gas
Category: Technology

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