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-Carbon Capture and Storage (CCS) should be a key technology in order to achieve a decline in the CO 2 emissions intensity of the power sector and other intensive industry, but this potential deployment could be restricted by cost issues as the International Energy Agency (IEA) in their last projections (World Energy Outlook 2013) has considered only around 1% of global fossil fuel-fired power plants could be equipped with CCS by 2035. The SiteChar project funded by 7 th Framework Programme of European Commission gives the opportunity to evaluate the most influential parameters of techno-economic evaluations of four feasible European projects for CO 2 geological storage located onshore and offshore and related to aquifer storage or oil and gas reservoirs, at different stages of characterization. Four potential CO 2 storage sites have been assessed in terms of storage costs per tonne of CO 2 permanently stored (equivalent cost based). They are located offshore UK, onshore Denmark, offshore Norway and offshore Italy. The four SiteChar techno-economic evaluations confirm it is not possible to derive any meaningful average cost for a CO 2 storage site. The results demonstrate that the structure of costs for a project is heterogeneous and the storage cost is consequently site dependent. The strategy of the site development is fundamental, the technical choices such as the timing, rate and duration of injection are also important. The way monitoring is managed, using observation wells and logging has a strong impact on the estimated monitoring costs. Options to lower monitoring costs, such as permanent surveys, exist and should be further investigated. Table 1 below summarizes the cost range in Euro per tonne (Discount Rate (DR) at 8%) for the different sites, which illustrates the various orders of magnitude due to the specificities of each site. These figures have how to be considered with care. In particular the Italian and Norwegian sites present very specific features that explain the high estimated costs. For the Italian site, the short duration of CO 2 injection associated with a low injection rate makes the CO 2 project comparable to a demo project. The Norwegian site is an offshore site located in a virgin area with high infrastructure costs and a combination of injection duration and injection rate that makes the derived costs very sensitive to the discount rate. The results for both UK and Danish sites confirm therefore the value range calculated by the European Technology Platform for Zero Emission Fossil Fuel Power Plants (ZEP).The main uncertainties in the costs are linked both to the choice of economic parameters (e.g. injected quantities, contingencies) and to the technical choice of operations. This has been studied by sensitivity analyses: for example, if an injection rate is halved and the injection duration is doubled, the Equivalent Storage Cost (ESC) increases by 23% (UK case at 8% DR). Introducing a water production well and water treatment facilities also increases the ESC by 23%, at ...

Résumé -Techniques de sismique pendant forage avec mesures de fond, inaugurées par l'IFP et ses partenaires en 1990-2000 -La sismique pendant forage (SWD), comprend toute technique opérée pendant que le train de tige est dans le puits, pendant le forage effectif ou pendant les manoeuvres d'ajout de tige ou de nettoyage. Deux techniques utilisées par l'industrie sont développées ici : -l'écoute sismique du trépan pendant forage (drillbit-SWD), usitée depuis 1986, qui consiste à enregistrer le signal avec un nombre indéfini de capteurs de surface, ainsi qu'un signal de référence représentatif des vibrations du trépan ; -le profil sismique vertical pendant forage (VSP-WD), qui consiste à enregistrer le signal émis par une source de surface avec un capteur sismique et un enregistreur intégrés à la garniture de forage (BHA). Cette technique émergente est opérée depuis l'année 2000 principalement par la société Schlumberger. Les deux techniques efficaces suivantes, assimilables à la sismique pendant le forage, ne seront pas discutées ici : -la technique de VSP dans le tubage (TLC), en particulier le VSP au câble avec outil descendu au câble dans un tubing de production ou un train de tiges de forage ; -le « VSP intermédiaire », qui consiste à acquérir un VSP conventionnel au câble avant la pose et la cimentation d'un cuvelage (casing), afin d'affiner le calage du puits à la sismique de surface et de prédire les zones en surpression au-dessous du trépan. Les développements récents effectués par l'IFP et ses partenaires en sismique pendant forage ont bénéfi-cié de la technologie de transmission temps réel à haut débit par fils et tiges câblés du système TRAFOR, qui a permis d'exécuter rapidement des tests terrains cruciaux. Pendant la période 1986-2003, la pratique d'écoute sismique du trépan visait une utilisation continue sur la profondeur totale du forage, avec peu de capteurs de surface, et sans adjonction d'enregistreur de puits pendant le forage : cette technique a donné des résultats mitigés, quasi nuls avec les trépans de type PDC (Polycrystalline Diamond Cutter). Les meilleurs résultats ont été obtenus avec l'usage de trépan de type tricône, lors du forage de formations plutôt dures, en évitant des valeurs faibles pour les paramètres de poids sur outil (WOB) et vitesse de rotation (RPM). L'IFP a introduit dans la technique d'écoute sismique du trépan les innovations suivantes : -les mesures de fond pendant forage, afin de mieux comprendre le processus d'émission sismique du trépan ; -l'amélioration de l'architecture mécanique de la garniture (BHA) en intégrant un élément amortisseur permettant d'optimiser la qualité du signal source émis et de diminuer les émissions secondaires indésirables ;Interactive Drilling / Forage interactif D o s s i e rOil & Gas Science and Technology -Rev. IFP, Vol. 59 (2004)

Development drilling occurs sometimes in areas where the surface seismic quality is poor. Drilling in such areas is risky enough to justify the application of drillbit SWD for seismic illumination ahead of the bit. A multidisciplinary project partially supported by the EC was undertaken combining the following techniques:Drillbit SWD, Seismic While Drilling survey using the drillbit as seismic source and many lines of surface receivers. The Bottom Hole Assembly (BHA) includes a roller cone bit, a shock absorber and a downhole reference sensor in between.EMWD, as Electro-Magnetic While Drilling wireless transmission surface to downhole. GEOSERVICES built a new Downhole Recorder Unit (DRU) integrated in the BHA in order to record the random axial drillbit vibrations in synchronization with a Surface Command Unit (SCU). Most of the commercial surface seismic recorders can be interfaced with the SCU. Large amount of uncorrelated seismic data are memorized both on surface and downhole while drilling, as the drillbit signal is available only when the drillstring is pulled out of the well. The objective of the method is to produce a seismic image of the geological structure around the first well in order to confirm the target structure, or to indicate the drilling targets of the following directional wells. The field operation is limited to one or two drilling runs around mid-target depth, due to operational and cost constraints. A full scale SWD reverse walkaway was recorded in this fashion around an ENEL well in a "no seismic result" area, near Larderello, using the OGS SEISBIT surface seismic recorder with 170 channels deployed over 6 radial lines. The whole chain of field equipment behaved successfully and good seismic reflections have been obtained. The present SWD reverse walkaway technique does not disturb the drilling process significantly. The time delay for processing needs to be reduced in order to render the method even more attractive. Introduction After positive completion of a drillbit experimental project conducted by IFP drillers and geophysicists, a step towards industrialisation was tempted through the following actions:cooperation with an MWD contractor to build a prototype tool recording the downhole reference signal while drilling.applying the new method using the new recording tool in an area poorly defined with surface seismic, for which drillbit seismic would improve understanding the geological structure and seismic propagation in the well vicinity. The Italian geothermal fields of Larderello and Mt. Amiata are characterized by a complex geological structure. Usually a cluster of geothermal wells is drilled from the same site in order to reach high temperature reservoirs, over 350°C in metamorphic rocks, down to 3500m. Well Seismic Profiling (WSP) complements the interpretation of reflection surface seismic profiles. The use of conventional wireline well seismic technique is restrained by the temperature and by the high seismic noise in geothermal wells. Therefore, the reverse WSP technique using the drillbit noise as seismic source looks very attractive. As the formations to be drilled are hard, only roller cone bits can be used, which is most favorable to the generation of drillbit seismic vibrations. Moreover, the unfavorable conditions of surface accessibility such as rugged relief, forest cover, sensitive permitting and environmental constraints make it difficult to operate surface seismic sources. Actually, similar exploration difficulties are encountered in many Oil & Gas field areas, locally or regionally.

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractDevelopment drilling occurs sometimes in areas where the surface seismic quality is poor. Drilling in such areas is risky enough to justify the application of drillbit SWD for seismic illumination ahead of the bit. A multidisciplinary project partially supported by the EC was undertaken combining the following techniques:• Drillbit SWD, Seismic While Drilling survey using the drillbit as seismic source and many lines of surface receivers. The Bottom Hole Assembly (BHA) includes a roller cone bit, a shock absorber and a downhole reference sensor in between. • EMWD, as Electro-Magnetic While Drilling wireless transmission surface to downhole. GEOSERVICES built a new Downhole Recorder Unit (DRU) integrated in the BHA in order to record the random axial drillbit vibrations in synchronization with a Surface Command Unit (SCU). Most of the commercial surface seismic recorders can be interfaced with the SCU. Large amount of uncorrelated seismic data are memorized both on surface and downhole while drilling, as the drillbit signal is available only when the drillstring is pulled out of the well.The objective of the method is to produce a seismic image of the geological structure around the first well in order to confirm the target structure, or to indicate the drilling targets of the following directional wells. The field operation is limited to one or two drilling runs around mid-target depth, due to operational and cost constraints.A full scale SWD reverse walkaway was recorded in this fashion around an ENEL well in a " no seismic result " area, near Larderello, using the OGS SEISBIT surface seismic recorder with 170 channels deployed over 6 radial lines.The whole chain of field equipment behaved successfully and good seismic reflections have been obtained. The present SWD reverse walkaway technique does not disturb the drilling process significantly. The time delay for processing needs to be reduced in order to render the method even more attractive.