parts, numerical simulation is the most eYcient and the least expensive means available. A constitutive equation describing Most of the numerical simulation software on the hot properly the behaviour of the powder during hot pressing isostatic pressing ( hipping) process is based on viscois a prerequisite. plastic modelling of densi cation, such as the wellThe two parameter viscoplastic model proposed by known Abouaf 's model. These constitutive equations Abouaf 1 with an implicit coupling between isotropic and are generally obtained from a viscoplastic potential deviator parts of the stress state is often used. This model depending on Green's equivalent stress. An implicit was initially implemented in COMPACTII, software develcoupling between isotropic and deviator parts is oped by the CEMEF. It has been then implemented in therefore only de ned by an equivalent stress. A new other software: ZEBULON by Nicolle 2 and ABAQUS by viscoplastic formulation proposed by Stutz intro-Kim. 3 This model is interesting because of its simplicity duces an explicit coupling between isotropic and which makes it easy enough to implement in numerical nite deviator parts of the stress state, allowing then more element software. Its ability to model correctly the hipping exibility to take into account the experimental results process depends on the materials involved in the powder achieved from isotropic, die compaction, and creep and the container but also on the hipping pressure and tests. This paper deals with the presentation of this new temperature cycle. In particular, during the temperature rise formulation which has been implemented in the nite from initial to hold values, the higher the applied temperelements software PreCAD, and the subsequent changes ature the better the modelling; the slower the temperature observed in numerical simulations. These simulations rise the worse the modelling. This remark is valid for achieved with PreCAD software, are compared with all the hipping modelling by taking into account only the an experiment on a complex part manufactured by viscoplastic deformation of the powder. CEA Grenoble.PM/0985 Many authors, such as Sanchez 4 and Kim 3 have shown, through diVerent numerical simulations of hipping, that Dr Sanchez and Dr Federzoni are with CEA Grenoble/ the Abouaf 's model is not satisfactory in many cases; most Service Mate ´riaux et Proce ´de ´s, 17 rue des Martyrsof all when the stress state is notably deviator. The model 38054 Grenoble Cedex 9, France. Dr Ouedraogo proposed by Stutz 5 is aimed at correcting this insuYciency

Hot isostatic pressing (hipping) is a manufacturing process capable of producing mechanical parts in only one operation by the hot forming of metal powders. The aim of this process is the production of net shape parts notably for aeronautics or nuclear applications. In the past, the trial and error method was used in order to find the right container and insert geometries giving the net shape parts. Several prototypes must therefore be manufactured before a successful conclusion is reached. This forming procedure results in expensive developing costs due to the quasi unitary production, pressure and temperature environment and the high temperature tooling involved.Numerical simulation raises hopes on the optimisation of this manufacturing process through the use of viscoplastic constitutive equations implemented in the finite elements software PRECAD/M.The rheological functions of this viscoplastic model are usually determined by assuming that the mean pressure in the sample is homogeneous and equal to the external applied pressure. The numerical simulations of hipping experiments show that this assumption is often false: pressure is partially transmitted to the powder because of the container rigidity. New rheological functions have been determined with the stress values obtained by numerical simulation of these tests. The new numerical simulations are then in better agreement with the experimental values and the prediction of an industrial complex part final shape is also improved. PM/1083 Dr Sanchez is with Federal Mogul Operation France/ Centre Technique, Voie des Collines, 38800 Le Pont De Claix, France. Dr Ouedraogo (Evariste.Ouedraogo@ hmg.inpg.fr) is with Laboratoire 3S (Sols, Solides, Structures), Domaine Universitaire, BP 53, 38041 Grenoble, France. Dr Dellis is with CEA/DEN/

No abstract

Historically, electric-submersible pumps (ESP) were designed for a production above 3,000 BFPD. For lower flow rates it was necessary to install another artifical lift method such as beam pump (BP). In the Caño Limón and La Cira-Infantas fields, located in Colombia with 30 and 98 years of production respectively, the number of wells with flow rates lower than 1,000 BFPD has been increasing as well as the number of wells with BP as a lift system. The increase of failures in BP systems, and the greater cost of the completions compared to ESP, made it necessary for the analysis of other artificial lift methods to handle the required flow rates. Therefore, in 2013, the implementation of ESP technologies with a nominal flowrate of 1,000 BFPD were carried out without failures associated with the ESP system, showing that they were able to work under such conditions, reaching rates between 50 and 1,000 BFPD, thus becoming an effective option to replace the wells with BP, as long as the conditions of pressure and submersion allowed it. In La Cira Infantas field, 60 wells with rod faults of the BP system have been successfully replaced by ESP systems with flow rates ranging from 400 to 2,000 BFPD. This work explores the possibility of installing ESP technology in wells where it was not previously seen as an option, presenting the results of the implementation of this technology producing even lower flow rates than those in the initial sizing, reducing the number of failures and the costs associated with the continuous interventions of the Mechanical Pumping systems.

No abstract