Reservoirs characterized by high temperature, high-pressure, medium high cementation strength, low porosity, and low permeability, in general, are not affected by sand production issues. Since 2009, however, it is known that cases exists where sand is present and may represent a significant technical problem (e.g., the the Dina II condensate gas field). In the present study, the main factors affecting sand production in this type of reservoir are considered (mechanical properties, stress fields, production system, completion method and gas flow pattern changes during the production process). On this basis, a new liquid-solid coupled porous elasto-plastic 3D sand production model is introduced and validated through comparison with effective sand production data. The related prediction errors are found to be within 15%, which represents the necessary prerequisite for the utilization of such a model for the elaboration of sand prevention measures.
As an important part of the Christmas tree, the sealing performance of the flat gate valve is very important, and the O-ring seal is the most commonly used seal in the flat gate valve. Therefore, the research on O-rings is particularly important. For the flat gate valve with a single gate, its structure has gradually developed from a single seat seal to a double seat seal. This article mainly analyzes the sealing principle of the double seat in the ultra-high pressure flat gate valve and the influence of the pre-tightening force of the sealing ring on the sealing effect. Using finite element analysis software, a two-dimensional axisymmetric model of the double valve seat sealing structure was established to study the non-metallic sealing performance of the valve seat. The Mises stress, the maximum contact stress of the sealing surface, and the contact area of the sealing surface of the O-ring seal under different compression ratios are analyzed. The results show that when only the sealing performance and pre-tightening force requirements are considered, an O-ring with a larger wire diameter should be selected as much as possible. When considering the service life of the O-ring seal, the compression rate of the seal ring should not exceed 20%. Therefore, the selected seal ring wire diameter is 3.75mm within the recommended seal ring compression rate range.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.