External Casing Packers (ECP)
Continuous Mandrel ECP assemblies are designed with packer elements in 4 Foot (1.22m), 10 Foot (3.05m), and 20 Foot (6.10m) lengths. World Oil Tools packer elements soundly conform to irregular or washed-out hole diameters. Steel reinforcement slats are used within the elements to ensure that the ECP self-centers itself in vertical, deviated, or horizontal wellbores.
Tools are available in Standard and Special clearance models. Standard clearance tools are used where higher differential pressures are encountered across the packer element. Special clearance tools are used for applications where restricted hole diameters may occur.
Continuous Mandrel ECP assemblies are typically inflated with cement displacement fluid. An integral screen prevents coarse particles from entering the valve system. The valves are designed with high quality materials, which will not erode when abrasive materials are pumped through the system.
The World Oil Tools valve system provides positive closing, after the element has been fully inflated to pre-determined pressure. After the shear valve has shifted to the final closed position, a mechanical locking device ensures that no further movement will occur.
World Oil Tools inflatable elements are available with Standard and Advanced elastomer compounds. Standard elastomer compounds may be used for temperatures up to 240° F (115° C). Advanced elastomer compounds are made available for applications in which temperatures reach up to 350° F (180° C).
Features & Benefits
- The continuous one-piece mandrel eliminates the need for internal threaded connections. Mandrel specifications are identical to the casing used in the well.
- The Valve system is located above the packer element. Valve operation is not affected by unpredictable pressure changes below the element.
- Superior anchoring system prevents element rotation, and packer shoe travel, while tools are run into the well.
- World Oil Tools ECP’s are manufactured with high strength steel materials suitable for H2S and CO2 environments.
- Shear pins in the valves may be easily replaced in the field, allowing the operator greater flexibility when well conditions change.
TO PREVENT LOSS OF CEMENT
External Casing Packers may be positioned in the casing string directly above a lost circulation zone. The packer effectively prevents the loss of high-density cement slurries into the lost circulation zone. For these applications, a second stage cementing operation is normally performed above the ECP, after setting the packer.
TO PREVENT GAS MIGRATION THROUGH CEMENT COLUMNS
In many wells, gas migration through cement slurry can be prevented by setting an External Casing Packer directly above a high pressure gas zone. Improved cement integrity will be achieved.
TO PREVENT UNWANTED WATER PRODUCTION
An External Casing Packer may be positioned slightly above an oil-water or a gas-water contact, in order to minimize water production from those zones.
TO MINIMIZE DAMAGE TO SENSITIVE FORMATIONS AND BAREFOOT COMPLETIONS
In the past, barefoot completions were used to minimize formation damage to production zones. However, today’s technology, using under-balanced drilling methods, allows drilling of the well to the required total depth, and to set External Casing Packers directly above sensitive formations.
FOR CENTERING CASING IN HORIZONTAL WELLS
Several External Casing Packers may be used on horizontal casing strings in order to centralize casing and to ensure even distribution of cement around the casing.
External Casing Packers may be positioned at one or more points on slotted liners. These packers may then be set at a later date, using cup-type tools.
ECP Valve System
World Oil Tools ECP’s are designed with a minimum two valves per assembly, depending on size. The valves allow the ECP to be inflated and ensure that once inflated the pressure is maintained inside the element. The opening valve prevents any fluid from entering the packer element until a pre-determined pressure is reached inside the casing. The closing valve is sheared to the closed position once the inflate packer is fully expanded, and a pre-determined pressure is reached inside the element. Once internal casing pressure is bled off, the opening valve then moves into a locked closed position, and can never be re-opened. This is a safety feature that prevents damage to the casing in the unlikely event that the packer element was to rupture.
Each World Oil Tools valve is specially Hard-Kote treated. Testing shows, that when inflating using large inflation volumes, which can be encountered on larger assemblies, severe washing and erosion will occur in ECP valves. Hard-Kote treatment provides a surface hardness in excess of Rockwell (Rc) 80, which minimizes the effects of abrasives. ECP valve pressure settings may be easily changed on location, just prior to running the tool using the supplied shear pin cards.