Syntactic Foam as Mitigation against Thermally Induced Trapped Annulus Pressures on the Linnorm field
Master thesis
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http://hdl.handle.net/11250/240024Utgivelsesdato
2013Metadata
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Sammendrag
An investigation on the feasibility of a crushable foamwrap productfor mitigation of annulus pressure buildup on the Linnorm projecthave been performed. Several different aspects of this technology havebeen investigated, including the collapse behaviour of the foam wrapand fluid behaviour when exposed to heat, HSE issues related to theproduct and the practical aspect around using this solution.A Literature study revealed that the annular pressure build-up, whena crushable foam is in place, have not been formulated hence a mathematicalmodel have been developed, explaining the pressure pressurebuild-up when the foam wrap is in place. This model have not yet beenverified since it requires monitoring of the B-annulus in a well that isyet to be drilled. Data describing the thermodynamic properties of annularfluids, needed to calculate the annular pressure build-up simplydoes not exist to the authors knowledge, hence the pressure build-upin the model have been calculated on the basis of using standard seawateras this is the only saline solution where the thermodynamic datais available. Laboratory measurements revealed that once the matrixfracture pressure is reached, fluid start propagating through the crackand into the collapsed glass spheres. Simulations on the cementing haveshown that it is possible to install the crushable foam-wrap withoutfracturing the foam in some sections. The flow restrictions however,due to reduction in annular clearance, creates a need to design a foamwith a collapse rating.With the information that is currently available, it is not possible togive a recommendation on what vendor to progress with. So far, bothvendors product qualify for Linnorm use based on the available information.3