OptiPac screens were used to gravel pack 4,347 ft of open hole in the North Sea—a world record.

 

Optimal gravel packing requires a total-system approach that includes the screen hardware, tools, fluid chemistries, software, and services needed to extend the life of the well and optimize production.

This approach has made Schlumberger a leading player in the field. The company recently gravel packed a record 4,347 ft of open hole in the North Sea—the longest interval completed with OptiPac* Alternate Path† openhole gravel-pack screens worldwide. These screens use shunt tubes and nozzles to bypass bridges and fill in voids that can occur when gravel and frac packing. Thus, they minimize the likelihood of incomplete gravel packs, which can expose long intervals of screen to erosion and plugging, leading to hardware damage and subsequent completion failure.

In complex reservoirs, multizone completions can improve both efficiency and recovery. Multizone gravel packing is well established in cased holes. Alternate Path screens and shunted swell packers provide a solution for open holes but also have some drawbacks.

The packer swelling process takes several hours—even days—thereby increasing opex while the rig waits. If the operator starts pumping gravel before swelling is complete, gravel can enter the space between the packer element and the wellbore, preventing an effective seal and resulting in a less-than-optimal completion.

Save rig time and completion costs

The new OSMP* OptiPac service mechanical packer from Schlumberger addresses all these concerns. Rated to 5,000 psi and 325 degF, this mechanically activated, hydrostatically set packer is equipped with Alternate Path shunt tubes and provides zonal isolation in both conventional and extended-reach openhole wells.

Schlumberger OptiPac service mechanical packer

The OSMP packer addresses the issues of long setting times and incomplete zonal isolation encountered with the use of swell packers for multizone openhole gravel packing.

Completion fluids are displaced and the packer is hydrostatically set in a matter of seconds as the setting tool moves through the packer. Gravel packing can begin immediately, saving a significant amount of rig time. Once the uppermost zone is packed and pumping pressure increases, gravel is diverted through the shunt tubes and begins filling the screen-wellbore annulus below the packer.

Additional time and cost savings can be achieved by using these packers to isolate nonproducing areas in multizone wells and only gravel packing above and below.

Achieve effective zonal isolation

The OSMP packer can be equipped with a shunt tube isolation valve, which is closed once gravel packing is complete, preventing any unwanted communication between zones. The valves are closed while the washpipe is being removed.

If water breaks through a producing zone, a seal assembly can be run inside the screen completion to create a secondary isolation. This allows unrestricted flow from other zones without production from the water zone. If the existence of a water zone is known before the well is completed, shunted blanks can be used with the OSMP packers to completely bypass the zone without gravel packing it.

The new mechanical packer’s design is an extension of the field-proven Alternate Path shunt tube technology. Since 1995, Schlumberger has installed more than 1,400 Alternate Path systems for multiple operators in more than 30 countries.

Maximize results with fit-for-purpose fluids

The Alternate Path system is complemented by a wide range of fluids, including ClearPAC* polymer-free viscoelastic surfactant (VES) gravel-pack fluids, which provide superior gravel suspension performance and shear recovery at lower surfactant concentrations compared with other VES fluids. They also exhibit low friction pressure during pumping compared with polymer-based fluids, making them ideal for gravel packing long horizontal intervals with Alternate Path screens.

ClearPAC fluids minimize formation damage and are compatible with oil-based and water-based muds. Formulations include fluids suitable for standard and high temperatures and fluids suitable for both gravel packing and filtercake cleanup. They exhibit viscosity reduction on contact with crude oils or on dilution with brine—no breaker is required to reduce viscosity after the gravel-pack operation is complete.

This integrated approach combined with reliable openhole zonal isolation is expanding the operating envelope for multizone openhole gravel packing. Wellbore profiles and completion designs that were previously unattainable are now well within reach.

For more information on OSMP OptiPac service mechanical packer click here. 

*Mark of Schlumberger

† Mark of ExxonMobil; technology licensed to Schlumberger