Swellable Packers Provide a Brownfield Water Management Solution in Open and Cased Hole – Case Histories Including Straddles, Plugs, Slimhole Sidetracks and Testing In Corroded Casing

Abstract

More than two-thirds of the world's oil and gas is currently being produced from mature fields, and although new prospects continue to be discovered, the industry is realizing that the older finds, now mature, are significantly larger than originally thought. Therefore, much of the world's future oil and gas production will continue to depend on brownfield production. Traditionally, when wells in these fields started to show production declines, operators often chose to abandon them rather than consider rework operations, since most production declines resulted from difficult-to-remediate unwanted water or gas production. In addition to water and gas influx, many fields had less-than-ideal production environments that contained CO2 and H2S, causing corrosion of tubulars. Realization of the need to revisit mature-field production has encouraged new technologies and remedial options to be developed. One of the recently proven technologies, swellable-elastomer packers, has enabled successful workovers, sidetracks, and re-drills that might otherwise have been too difficult, unreliable, or too expensive to be performed a few years ago. The packer uses the swelling properties of rubber in hydrocarbon or water to expand so that the annulus around the pipe is sealed. This capability has proved to be a great advantage in older wells where corroded, pitted and otherwise irregular surfaces in addition to reduced wall thicknesses due to corrosion make setting and sealing of conventional packers very difficult. This paper provides case histories and applications of swellable straddles and plugs in openhole and cased-hole scenarios that have enabled shut-in wells to be placed back into production. The discussion will include coiled-tubing tool and wireline deployment methods, wells in which swellable packers have been run as part of the completion string, and testing of swellable packers that provided seals in corroded casing. The principles and techniques involved are applicable to brownfield situations worldwide. Introduction Since the introduction of swellable elastomer units approximately 10 years ago, approximately 20,000 of these units have been delivered to operators worldwide. Since then, the scope of possible applications has increased constantly as new ideas, trials, and technological advances have been introduced. Swellable-elastomer packers are run in both open- and cased-hole wellbores, in extended-reach-drilling (ERD) wells, in multilateral (MLT) wells; with feed-through in conjunction with intelligent completions, in hydraulically fractured wells, in combination with cement, and in producers and injectors in low-temperature to high-temperature/high pressure (HT/HP) fields.

Diffusion-based swelling in elastomers under low- and high-salinity brine

“…Diapers are made of superabsorbent material that absorbs liquid but remains apparently dry. Swelling elastomers are used in oil and gas wells for zonal isolation, [10][11][12] cementless completions, 13 well remediation, 14 and so on.…”