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This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper OTC 20134, ’Siri Pilot Project - First Offshore Extra Heavy and Viscous Oil (12.3 API) Ever Produced,’ by Alexandre Dutra Sayd, Andre Luiz B. Moco, Celso C.M. Branco, Edson T. Kato, Ivan Parreiras de Carvalho Jr., Joao A. Rosseto, Jose Augusto da Silva Neto, Josiane L. Diniz, Marcelo Brennand, Marcelo Guarda, Miguel Pittella Franco, and Thomas Edison Brasil, Petrobras, originally prepared for the 2009 Offshore Technology Conference, Houston, 4-7 May. The full-length paper describes the appraisal and pilot testing of a large, offshore highly heterogeneous carbonate 12.3ºAPI reservoir in 100-m water depth. The successful pilot production started on 31 March 2008 to the floating production, storage, and offloading (FPSO) vessel Cidade de Rio das Ostras (Fig. 1). Since then, pilot production has been monitored closely by permanent-down-hole-gauge (PDG) and electrical-submersible-pump (ESP) sensors used to update a reservoir-simulation model. Preliminary results show more-viscous oil than initially expected in a more complex reservoir. Introduction In the early stages of exploration and production of the Campos basin offshore Brazil in the late 1970s and early 1980s, a shallow (900-m true vertical depth) Siri carbonate reservoir was discovered in water depths of 100 m. Although the volume in place was large (currently estimated at more than 300 million m), it was considered noncommercial because of the 12.3°API oil gravity and 320-cp viscosity. At that time, there was an abundance of lighter oils to be developed beneath the same area. In addition, the technology for extracting such heavy and viscous oil in an offshore cold environment had not been developed yet. In 1993, a vertical development well, designed for the deeper reservoir, tested and collected a bottomhole oil sample. Operational problems during the well test, including water production, made it difficult to quantify reservoir parameters. In 2002, new studies were made, which led to the drilling and testing of a pilot vertical well, later sidetracked to a long-horizontal-section (2000 m) well, revealing a better-than-expected reservoir scenario. An ESP-aided flow test in the vertical well produced an impressive productivity index. In this context, the Siri reservoir appeared as a candidate for a pilot production project. Many other heavy- and extraheavy-oil discoveries were made in Campos basin, which caused additional interest in testing and development technologies.
ABSTRACT The behaviour of the Jarmelo granite (Guarda, Portugal) in uniaxial compression is presented. The grain size, texture and mainly weathering are responsible for the variation of the strength and deformation properties of the granite. The weathering process increase the porosity and reduces the unitweigh.The increase of porosity above2%is marked by a significant reduction of the mechanical properties of the granite. The strength of the granite reduces 94% from grade I to grade IV and increases the dispersion of the results. The rupture behaviour is brittle. The tangent, secant and initial deformation modulus, all decrease with weathering. In the first three grades of weathering the stiffness of the sample increases with deformation while the opposite occurs for grade IV. The maximum axial strain at rupture increases proportionally with weathering, presenting a low variation coefficient. 1 INTRODUCTION The strength and deformability of crystalline rocks has been studied by a great number of authors in the last decades. As each material has its own behaviour, influenced by the mineralogy, texture and weathering, it is necessary to conduct tests to obtain its specific properties. This work concerns with the study of the Jarmelo granite, close to the city of Guarda, central Portugal. 2 MATERIALS The Jarmelo granite, as well as the surrounding granites are derived from the partial melting of relatively hydrated sediments, considered as sin-orogenic, sin-F3 (Ferreira et al., 1987). The sampling of the granite with weathering grades from I to IV, according to the classification of the IAEG (1981), was done after a surface geological reconnaissance. The average grain size of the Jarmelo granite is 3mm(Teixeira et al, 1963) and the texture is granular. The main minerals are quartz, microcline, albite, oligoclase, and muscovite. Biotite, apatite, sphene, zircon and magnetite can also be found. Secondary minerals are caolinite, sericite, chlorite, iron oxides, iron hydroxides and epidote. The mineralogical study was done under the optical microscope, allowing obtaining the modal composition presented in figure 1. A summary of some physical index properties of the rock material, with increasing weathering, is presented in table 1. The samples used to determine the index properties were the same that were used to execute the mechanical tests. 3 METHODS 3.1 Sample preparation The sampleswere obtained in the field by coring, using diameters from 80 to 100 mm. 3.2 Tests procedures Uniaxial compression (UC) tests with controlled strain were executed (Fairhurst & Hudson, 1999; Brown, 1981).To evaluate the deformations, two alternative measurementswere used:a system using linear transducers;three LVDTat angles of 120° for the measurement of the axial deformations; four LDT at angles of 90° located at half height of the test samples, for the measurement of the lateral deformations; electrical strain gauges glued to the samples (encapsulated strain gauges of 20mm long and 350 ohm). Its appliance did not offered problems in the less weathered granite, in opposition to theweathered samples of grade IV.
Tunnelling experiences obtained from projects in Madeira, Iceland and the Faroe Islands will be presented in this paper. These experiences include such as tunnelling conditions in general, support and grouting philosophy and also various types of problems encountered and the solutions found to deal with them, In particular, tile applicability of the most common rock mass classification systems will be discussed in tile paper. Tunnelling in volcanic rock mass have been experienced elsewhere too, however, as a first step in gathering experiences it was considered sufficient to include projects from the countries mentioned above. If this exercise would provide any systematic findings that lead to believe that tunnelling in volcanic rock masses is different compared to other rock masses, a further approach on an increased database would be suggested. 1. INTRODUCTION With a rather diversified background the authors of this paper found an interesting interface, namely that related to tunnelling in volcanic rocks. Two of the authors have their experience and background from the Madeira Island, whilst one has his experience particularly from the Nordic countries where tunnelling in volcanic rocks have taken place in Iceland and tile Faroe Islands. On this basis this paper will try to draw the common aspects of tunnelling in volcanic rocks from a number of projects in these countries mentioned above. Common for these is also the fact that they are small groups of islands situated in the Atlantic sea hundreds of kilometres out from the nearest mainland or continent. It was found an interesting exercise to try to draw up the tunnelling experiences from a number of selected projects in these countries and identify common problems and how these were solved. The projects that will be discussed in particular include such as tile road tunnels from Funchal city - Cot a 200 (Marmeleiros: Penteada and Quinta da Palmeira twin tunnels): Porto da Cruz (Cruz da Guarda, Serrado single tunnels); and Água de Pena (Queimada single tunnel). Further, tile water supply and hydropower tunnels of Fajã de Ama, tile connection tunnel of Encumeda to Ribeira Grande São Vicente and in the multipurpose tunnels of Socorridos. From the Nordic countries the experience from subsea road tunnels in Iceland (tile Hvalfjördur tunnel) and the Faroe Islands (the Vagatunnilin tunnel) will be presented together with some general experiences from a wider range of projects. Rock mass classification using various classification systems will also be discussed. In the Nordic countries the Q-system developed by Barton and his colleagues has been the dominating whilst in the Madeira Island the Bienawski geomechanic (Bieniawski, 1989, in Hock. 1997) is most commonly applied. Neither of these two systems were established and developed with particular focus on volcanic rock masses, and are they really applicable as reliable tools these geological circumstances? This paper will discuss these classification systems based on the experiences from the projects mentioned above and specifically focus on the parameters used in the application of quantitative rock mass classification systems in volcanic, basaltic rock types.