New swellable system seals microannular voids, centralizes pipe
Weatherford International launched its Micro-Seal system, designed to isolate microannulus pressure and avoid remedial cementing operations, at the 2010 IADC/SPE Drilling Conference in New Orleans on 2 February. The system features proprietary hybrid-swellable elastomer elements that allow it to conform to and seal against microannular voids between the cement sheath ID and the casing OD to improve overall cement integrity. When combined with the right centralizer technology, mud removal during primary cementing operations can be improved, thereby improving wellbore stability.
Distributed along the cemented tubulars, the swellable seals provide a series of response points that ensure fluid migration is met and stopped wherever it enters the microannulus between the pipe and cement.
Unlike conventional, single-fluid swellable elastomers, this technology is based on swellable elastomer that is activated by oil, water or a mixture of both. The elastomer is formulated to meet specific swelling objectives and wellbore compatibility issues as the well dynamics change over time. The hybrid elastomers in the system are a relatively slow swell-rate formulation, designed for microannulus isolation. However, these elastomers can also be customized to address specific design objectives in terms of swell time, swell ratio and temperature stability.
Micro-Seal products consist of a slip-on seal unit that can be used alone or in conjunction with the company’s bow-spring centralizer, bow-spring centralizer sub or rigid centralizer. These can be used in well construction applications such as ultra-tight clearance casing programs, underreamed open-hole sections, extended-reach wells, gas or LPG storage wells, injection wells, wells to be fractured, and any well with a risk of microannular fluid migration.
Weatherford is offering models and an animation of these cement assurance tools at Exhibit #607 to at the Drilling Conference.