This paper demonstrates the connection between laboratory measurements and field results from gelant treatments in production wells at the naturally fractured Motatan field in Venezuela. Using a HPAM polymer with an organic crosslinker, laboratory corefloods revealed that under reservoir conditions, the gel provided oil and water residual resistance factors of 20 and 200, respectively. This gel was placed in several production wells in the Motatan field. In Well P-47, 1,000 bbl of this gel reduced the water cut from 97% to 64% and increased the oil production rate by 36%. The success of these treatments depends on the distance of gelant leakoff from the fracture face and the in situ residual resistance factors in the oil and water zones. Analyses were performed to determine these parameters, based on formation permeabilities, porosities, fluid saturations, fluid properties, fluid production rates, and pressure drops before, during, and after gelant placement. Accurate pressure drops before, during, and after gelant placement were particularly important. Sensitivity studies were performed to demonstrate their significance and the impact of measurement errors. A methodology is presented for optimizing the volume of gelant injected for these applications. Introduction For most gel treatments applied for conformance improvement and water shutoff, design procedures (especially the methods for treatment sizing) were strictly empirical - a fact that is partly responsible for the erratic success rates of these treatments. Many water shutoff treatments rely on the ability of polymers or gels to reduce permeability to water much more than that to oil. Unfortunately, the magnitude of this disproportionate permeability reduction cannot yet be predicted a priori under reservoir conditions. Since laboratory studies are rarely performed before field applications, widely varying field results are not surprising. In some cases, individuals have suggested that field results with gelant treatments were at odds with laboratory data or with basic petroleum engineering principles. Depending on their background, operators, service companies, and researchers naturally place more credence in some observations than others. For example, a service company may prefer to emphasize certain field observations to rationalize an explanation that researchers find in contradiction with laboratory findings or in violation of established petroleum engineering principles. Consequently, all data (field, laboratory, and theoretical) should be considered when applying and evaluating field applications of gelant treatments. Of course, observations can be misinterpreted. Laboratory experiments may be botched or performed in misleading ways; theoretical or numerical studies may suffer from incorrect assumptions (e.g., garbage in/garbage out); and field results may be interpreted incorrectly. However, by combining sound laboratory, theoretical, and field observations, a consistent picture should emerge that can be used to improve the success rate for future field applications.

fax 01-972-952-9435. AbstractOrocual field is an anticline located in the East of Venezuela within El Furrial Trend. The San Juan Formation, a tight Late Cretaceous-Early Paleocene sandstone, is one of the best producing reservoir of Orocual. Located at a depth of about 14000 feet, it is characterised by a low matrix porosity (5 to 6%) and permeability (below 5 mD in average). Very quickly identified as a possible fractured reservoir due to the difference between producers' performance and petrophysical data, this hypothesis was later confirmed with the acquisition of cores and borehole image logs 'BHI'. Both show the presence of numerous open or partially open tectonic fractures.The present paper focuses on one of the four structurally compartmentalized fault blocks of the field that presents the highest potential of reserves. It is shown how all available data, geology (Bore Hole Image logs, cores and wireline logs), geophysics, and reservoir engineering data (production data, flowmeters, welltests) were combined to identify the main types of fractures, to predict their occurrence in the reservoir and to determine the hydraulic properties of the different fractures sets. The DFN approach was used to characterise the natural fractures at well scale and to model the full field 3D fracture network. From BHI and core analysis, it was found that the formation Vshale and the porosity were the main geological drivers on natural joints (small scale fractures) occurrence. Those properties associated to the matrix were used to populate in 3D the fracture network model. A second type of fractures, large scale fractures associated to faults, although not identified on wells but strongly suspected to exist, have also been included in the 3D model. The model was hydraulically calibrated first through simulation of a measured flowmeter log with the DFN model and then through match of the KH measured from transient welltests with the KH derived from the model.The outcome of the study is a reliable set of fracture properties that can directly be used in the 3D simulation model in order to improve the current history match and evaluate injection scenarios for the future.

Orocual is the most complex Field in Monagas, eastern Venezuela. Due to its complexity it has been divided vertically into two zones: shallow (heavy oil) and deep (light oil and condensate). The OOIP in shallow reservoirs is reported as 3500 MMSTB. The reservoir pressure is close to original conditions due to low historical production. Therefore, the current oil recovery factor is less than 1%. To date, cyclic steam injection pilot was applied to 5 wells and the initial oil rate showed to be as high as five times the cold production in vertical wells and six times the cold production for horizontal wells. According to the results of the pilot test, the future development of shallow Orocual will be mainly based on the application of thermal processes. This paper shows a methodology to design an exploitation plan through the application of thermal process. The first step involves analyzing the reservoir by sectors in order to determine which thermal process is appropriate to the reservoir; the second step is building sector models to simulate each process and optimize operational parameters. For the first time cyclic steam injection, steamflooding and steam assisted gravity drainage were simultaneously simulated in the same model. According to this study it is possible to maximize the production of these reservoirs, accelerate the exploitation of its reserves and optimize operational parameters in thermal recovery, as well as determine critical factors for each process. This study shows that numerical simulation of complex process can be efficiently carried out in FullField scale.

In this second part another group of processes of surface treatment of materials in which has been employed a series of principles of the Physics are reviewed. Using technologies that employ these principles it is possible to modify the surface of materials in order to obtain improvements in their behavior, specially in regard to increasing their corrosion, wear or fatigue resistance. In particular, this work describes the processes of flame and induction hardening, surface treatments using laser beam, treatments that use concentrated solar energy and finally the processes of physical vapor deposition. All of them of industrial application, with the exception of the use of concentrated solar energy which, however, has an important potential due to the current situation of the renewable energies.

The objective of these two works is to show how a series of principles and concepts of Physics are applied (which are taught in the areas of Basic Sciences in Engineering careers), in various processes that are used to modify the surface of materials and thus provide them with improved properties particularly related to wear, fatigue and corrosion resistance, with the purpose that engineering students have greater evidence of practical applications and, therefore, of the importance of Physics for development of these technologies. As an example, in this first article, the Thermal Spray processes are presented and it is shown how Physics concepts are applied and have a prominent role both in the design and in the construction of the equipment with which they are made, as well as in the own generation of surface treatments. This is intended to give a sample and evidence the usefulness of Physics in this type of process to both students and teachers.