External casing packer

Expandable packer provides an effective and dependable steel barrier in the casing-borehole annulus, irrespective of hole shape and condition

Download PDF 联系我们 Related Resources

Overview

Seal the annulus for cementing operations, even in ovalized boreholes

External casing packers (ECPs) are robust expandable stainless steel devices designed to set at low pressures to achieve zonal isolation. They can be used for any stage cementing operation. These packers improve sealing performance compared with conventional packers, especially in irregular boreholes.

Casing-while-drilling (CWD) packer

Available for 13 3/8-in casings, the ECP CWD model is designed to resist aggressive conditions experienced during specialty drilling applications, such as with the Allegro™ casing- and liner-while-drilling services. Its annular sealing capacity for cement support and backup applications matches that of other ECP models; at the same time, it exhibits increased resistance to torque, shocks, and abrasion encountered during casing drilling.

Rated up to 5,000 psi [34.5 MPa]

Rated up to 320 degF [160 degC]

Qualified to API Spec 19OH V2

Applications

Cement backup
Primary cement improvement
Single-stage, multistage, or off-bottom cementing

Schematic shows 3 use cases for an expandable steel external casing packer.

Use cases for the external casing packer include stage cementing (left), off-bottom cementing above a low-pressure completion (center), and cementing above a lost circulation zone (right).

Benefits

Our external casing packer provides an effective steel barrier between the casing and borehole to prevent fluid migration in the annulus, eliminate crossflow during cementing, and stop gas migration during cement setting. It seals in any hole shape and condition, including oval, out-of-gauge, and irregular boreholes. The packer maintains casing rating by avoiding extra connections or casing ID reduction.

Rapid installation, on-demand expansion, and immediate sealing save rig time. The robust construction withstands reciprocation and rotation to pass through doglegs and tight spots, minimizing NPT.

Features

Simplified setting process with no moving parts
Compatibility with standard casing
Burst and collapse ratings equivalent to casing ratings
HNBR elastomer to ensure sealing even in washed-out zones
Self centralization during expansion

Case Studies

Illustration of an external casing packer isolating a thief zone to enable placement of a second cement stage to surface.

案例分享

Expandable Steel Packers Prove 30% More Cost-Effective for Stage Cementing

Lost circulation zone successfully isolated in 10 deviated, undergauge boreholes.

FAQs

Schematic shows the setting process for an expandable steel external casing packer.

Schematic of the setting process for an external casing packer.

How is the packer set?

The packer sleeve is expanded between the casing and borehole by applying pressure in the casing. This pressure is transmitted through the expansion port to the packer’s integral stainless steel sleeve. As the sleeve expands, it conforms to the shape of the wellbore. A patented thin layer of bonded elastomer ensures sealing in irregular boreholes. The expanded sleeve also serves to centralize the casing string.

The packer is built on a one-piece mandrel by crimping, with no hidden connections. Both ends are fixed and protect the expandable sleeve while running in hole. The robust construction allows the packer to be rotated and worked through doglegs and tight spots; full casing characteristics are maintained.

The expansion port features a valve system that permanently closes the port after the packer is set and a predetermined pressure is reached. This activation pressure can be modified by replacing an easily accessible shear pin. The valve also serves as a safety feature; if the packer is expanded in front of a severe washout, the valve closes, which prevents fluid loss.