Comprehensive Liner Solutions for Complex Deepwater Wells
Every year the number of deepwater wells drilled around the world grows, along with the expectations to drill and complete them as safely, quickly, and cost effectively as possible. Operators are increasingly looking to liner systems to help meet these goals.
Considered a viable alternative to long strings cemented to surface, liners are short casing strings run into the well and suspended below the wellhead within existing casing by a liner hanger. Running liners can provide many benefits:
- Minimizes rig time and associated costs for casing and cementing;
- Expands options for well designs;
- Enables deeper wells to be drilled with smaller, lower-cost rigs;
- Reduces drilling hazards by enabling quick casing of the open hole below previous casing;
- Creates an additional annular barrier compared to running long casing strings back to surface;
- Improves zonal isolation by reciprocating during well conditioning and rotating during cementing operations.
However, the increasing complexity of deepwater wells threatens the reliability of traditional liner equipment. Complex wells landed in hotter temperatures and higher pressures can often have ambient conditions that exceed 300°F (149°C) and 10,000 psi (69 MPa). In these extremes, liner equipment must provide a reliable barrier against gas migration or bypass and, in turn, ease the regulatory concerns regarding effective zonal isolation in deepwater wells.
Evolving to meet critical demands
To meet the increasing demands of liner systems in complex wells, Weatherford continues to advance its liner systems. Originally developed for the harsh conditions of the North Sea and onshore Canada, Weatherford liner systems have evolved to meet quality-critical applications including deepwater, shale, high-pressure/high-temperature (HPHT), and other challenging well construction environments. This evolution has recently led to the development of the comprehensive IntegraLine™ high-performance liner system with swage technology. Engineered for reliable service up to 15,000 psi and 400°F (103.4 MPa and 204°C), this integrated offering comprises four main components.
SwageSet Polished Bore Receptacle (PBR). The SwageSet PBR is designed to withstand burst and collapse effects when tied back to the surface. Made up to the liner-top packer, the PBR protects the liner running tools during deployment. The honed internal diameter provides a smooth surface for sealing and has been fully tested.
SwageSet and SwageSeal Liner-Top Packers. The liner-top packer plays a significant role in the liner system because it serves as an immediate point of isolation between the reservoir and the wellbore. Once set, the packer must seal and hold for the life of well - even in fully cemented applications.
For this reason, the SwageSet and SwageSeal liner-top packers meet the industry’s most stringent performance standards, which include the V0 rating established by the International Organization for Standardization (ISO). The V0-validated packers were tested under cycles of temperature and axial loading with zero gas bypass allowed. The packers provide standard service ratings of up to 12,500 psi (82.7 MPa) and extended service ratings up to 15,000 psi (103.4 MPa) for most sizes.
IntegraLine Liner Hanger. As the anchor that supports the weight of the entire liner casing, the liner hanger must be capable of holding heavy loads, often in excess of 1,000,000 lb (453,592 kg). The IntegraLine liner hanger is set hydraulically by converting an applied pressure to a mechanical force that sets the hanger slips into the parent casing, which results in less required downhole setdown. The hanger is well suited for complex wells in which deviation and buckling are likely and would hinder effective setting of mechanically set hangers. With robust Aflas seals, the liner hanger suits sour environments and bottomhole conditions up to 15,000 psi and 400°F (103 MPa and 204°C). A rotational version of the hanger enables rotation during the cementing process to ensure a uniform cement bond.
The unique design of the swage packing element incorporates a metal seal carrier that expands outward into the parent casing by use of a cone. The seal carrier has redundant Aflas® elastomer seals that are highly resistant to hydrogen sulfide (H2S) and carbon dioxide (CO2) up to temperatures above 400°F (204°C).
IntegraLine Tieback Seal Stem. When the liner casing must extend to surface (or tie back), a seal stem is used to stab into the PBR for the necessary pressure integrity. A new addition to the IntegraLine system, the IntegraLine tieback seal stem incorporates recent advances in seal materials and seal designs to extend its capabilities. Rated up to 15,000 psi and 400°F (103.4 MPa and 204°C), the tieback seal stem has a unique seal profile and Aflas material. Using the tieback seal stem makes the IntegraLine system a true HPHT liner-hanger solution.
In numerous field applications onshore and offshore, the various components of the IntegraLine system have performed successfully, both by themselves and in tandem.
In an onshore application in the Middle East, an operator deployed the PBR, liner-top packer, and liner hanger to form a reliable seal between the liner OD and the host-casing ID. The system was set at a TD of 6,850 ft (2,087 m) without incurring nonproductive time (NPT). Pressure-testing the packer to 5,000 psi (34.5 MPa) ensured proper zonal isolation from the liner-top to the shoe. This success enabled the operator to drill and complete the production zone of the well without losses. An operator in the Norwegian sector of the North Sea deployed an integrated liner system that included the PBR, liner-top packer, and hydraulically-set rotating liner hanger as a permanent isolation solution in three deep, highly deviated wells. The components were run to TDs that ranged from 10,328 ft to 16,896 ft (3,147 m to 5,149 m) without NPT. In each instance, the hanger was set by running a mechanical ball seat to provide the necessary pressure-tight chamber. Set-down weight through the PBR set the packer against the host-casing ID. Pressure tests in each well verified the setting of each packer, and the subsequent cement jobs provided reliable isolation from the liner top to the shoe. Liner-running and cementing operations were completed safely and without incident, which enabled the operator to drill and complete production zones as required.
More than HPHT
The IntegraLine high-performance liner system addresses critical wells not only in HPHT environments, but also in ultradeepwater and high-angle applications. With field-proven technologies rated to the most stringent industry standards, this integrated system ensures a reliable seal the first time and for the life of the application. As wells continue to become deeper, hotter, and more complex, the system offers a means to help operators achieve well construction goals and optimize the production potential of each well.
For more information on the IntegraLine system, visit http://www.weatherford.com/integraline.