Modeling Horizontal-Completion Deformations in a Deepwater Unconsolidated-Sand Reservoir

Abstract

Summary We present the development and results of geomechanical models and analyses used to assess the risks of compaction-induced deformation and potential failure of horizontal gravel-pack completions in a field located in deep water but at shallow depth below the seafloor. The target reservoir consisted of high-porosity, underconsolidated stacked turbidite sandstones, which are comparable to some of the more well-known, problematic compactive reservoir sands. The formations indicated a high level of risk of depletion- induced compaction, which could produce large deformations and potential failure of completion equipment in horizontal wells. Coupled poroelastoplastic geomechanical finite-element models were constructed to assess the risks of completion-equipment damage because of depletion-induced reservoir compaction. Both openhole and cased-hole gravel-packed completion configurations were analyzed. Details of the prepacked-screen assembly components were included in the models, such as the ribs between the base pipe and inner screen and the deformable epoxied sand between inner and outer screens. Model results presented in this paper include deformations of the completion equipment and stresses in the screen components, as a function of reservoir-depletion pressure. The results of the geomechanical modeling indicated that the overall compaction loading should not cause significant deformation of the specified completion equipment.