Swell Technology™ systems can make a difference to the bottom line

In an industry where methods are well established but seldom challenged, few people ever stop to consider if the technological starting points developed during the early days of the oilfield are still relevant.

Take well construction for example: are the limitations of today's casing solutions simply the restrictions imposed by materials available a century ago?

Easywell's Swell Technology™ systems have now enhanced more wells than expandables & surface controlled completions. It has gained a tremendous momentum through recent years, with yearly growth of 100-200%.

What is this technology, what can it do, and why has it been so rapidly accepted by the industry? The answer is traditional methods that have been used to isolate producing zones have in many cases been able to accommodate changes in the wellbore over the producing life of a well. Swell Technology systems provide a seal that continues to work long after installation by being adaptable to downhole events.

Easywell's Swellpacker™ and Waterpacker™ isolation systems use swelling rubber technology to offer operators a variety of completion sealing alternatives to cement, particularly when dealing with difficult environments such as irregularly shaped open hole, unstable formations and horizontal wells.

These systems can swell in excess of 200% of its original size to seal the annulus around the pipe to isolate zones. Once deployed, the rubber retains its flexibility, allowing the packer to adapt to shifts in the formation over time to retain the integrity of the seal. When used directly in open hole, it allows operators to dispense with the need and therefore the expense of cementing and perforating.

The Swellpacker™ and Waterpacker™ systems can be configured to set when exposed to hydrocarbons, water, or other fluids. They require no service tools or surface operations to be activated or set, reducing operational complexity, time and materials costs.

Some of the benefits that the operators experience when using the Swellpacker system are:

• The only interface with other well equipment is the threads and no tool operations are required.
• Well proven designs allow delay of swelling in oil based mud, enabling running without premature set in open hole.
• Installing open hole completions with pre-perforated liners or sand screens enables open hole advantages - reduced formation damage.
• Rugged construction allows reliable installation in sidetracks, multilaterals, extended reach wells and slimholes.
• The Swellpacker system is believed to be the only commercial spliceless cable feed-through product allowing SmartWell® completions without cable weak points improving long term reliability. Installation time is reduced by minimizing makeup time. In well consolidated boreholes, open hole valve installation can even enable downsizing of the whole well with significant well cost saving.

Waterpacker™ Isolation System

The Waterpacker zonal isolation system uses a special water-swelling, rubber-based elastomer developed by Easywell through extensive laboratory research and testing. Based on an advanced, new polymer formula, this elastomer utilizes the principle of osmosis to deliver long-term stability and reliability. Like Easywell's successful Swellpacker isolation system, the Waterpacker system uses rubber bonded to pipe and crimped end rings. Also, like the Swellpacker system, it can be used in both open hole and cased hole environments, including applications where no liquid hydrocarbons are present in the well.

Cement Assurance™ Tool

The Cement Assurance™ tool provides a reactive downhole means to address the micro annulus or channeling that occurs when the set cement debonds from the casing. It will remain dormant while encased in the cement sheath. Once the passage has opened up and liquids or gas attempt to flow through it, the Cement Assurance tool will then swell to close the micro annulus or channel and re-establish the hydraulic seal. The swelling rubber element can conform to almost any irregular geometry in the casing or cement.

The Technology

The Swellpacker system uses a standard oilfield grade tubular with layered rubber bonded along its length. The element swells by absorption of hydrocarbons which come from the reservoir, drilling fluid or another source. The thermodynamic properties of the rubber effect an attraction between the molecules which causes the molecular structure to stretch and allow oil to enter the structure. The swelling can cause a several-fold increase in the rubber's volume which is in excess of 300% in crude where the packer is unconfined. While the Swellpacker system won't swell in pure water, and only traces of hydrocarbon is enough, field applications have shown the packer will swell in water cuts as high as 98%. Swelling is homogeneous along the element length and the hydrocarbon doesn't degrade the rubber structure. It simply alters its mechanical properties by reducing the hardness, tensile strength and Young's Modulus. The timing of the process is possible to engineer and is controlled by the viscosity of the hydrocarbon being absorbed. A positive swelling pressure is developed that exceeds the surrounding pressure by a few tens of psi. This pressure differs from the differential pressure of the packer and is the maximum estimated pressure differential across the element. Differential pressure depends on the absolute swelling (hole size versus packer dimensions), not the swelling fluid.