The widespread use of FracPack technology in deepwaterreservoir has been a growing practice. Its purpose is sandcontrol and well stimulation. To-date, field applications andfracture treatments have been designed using traditionalhydraulic fracturing simulators that apply LEFM theories.While this is adequate for hard rocks (e.g., tight gasformations), the fracture geometry predictions fall short whenapplied to fracturing soft rocks. Soft rocks are normally atincipient plasticity and, hence, are prone to compaction.Compaction, or plastic rock deformations during sand controlFracPacks operations and disposal of drilling cuttings slurriesin soft layers. The capacity of the created fracture to store oraccept solids, the conditions of the rock strength near thefracture faces and the near well/fracture rock porosity orpermeability are all highly impacted by the rock compactionduring the fracture propagation process.The objective of the presented research is to assess the impactof compaction and plasticity on fracture geometry andformation properties around the fracture. In particular, it isimportant to quantify the details of the geometry of facturesgenerated during FracPack and waste disposal operations aswell as the porosity/permeability changes in the vicinity of thefracture faces.In the current paper, rock behavior is described by a variationof the Cam-Clay model. This model represents an inelastic,work hardening model that, depending on the loading path,could predict both compaction and dilatency, in a givenformation. This is particularly useful in modeling soft orelasto-plastic compacting formations since the fracturepropagation is heavily driven by the leak off into the formationand the in situ stress profile. Formation low permeability leadsto lower leak off rates, especially if the injected slurry has aleak-off control additive. This scenario leads to compaction ofthe rock along the fracture sides. High permeability at the tipresults in a large amount of fluid leak off into the formationcausing the near-tip zone to dilate during slurry injection andfracture propagation.The current paper presents results of fracture simulation incompacting rocks including fracture geometry, fracturingpressure and porosity/permeability alteration around thefracture. In the previous paper, results of finite element modelprovided a benchmark to simulation results. The present work,on the other hand, shows the extent of formation disturbanceand porosity/permeability alteration, as well as proppedfracture characterization in FracPacks. Finally, the modelresults addressed the disparity between conventionalFracPacks designs and actual treatment data. The observationsconfirm the need for careful consideration of rock plasticity infracture simulation to avoid FracPack failures and minimizethe absence of TSO response in some field implementations.
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