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Abstract. The paper describes the petrophysicai evaluation of several wells in the Motatán field, located at the foothills of the Andes, in western Venezuela. Hydrocarbon production comes from various Eocene sands at depths of 8000 to 12 O00 ft (2440-3650 m). The sands are of low porosity and permeability. The correct evaluation of their petrophysical characteristics has always been a challenge to those entrusted with production predictions. The absence OC water sands and the existence of a significant amount of streaming potential make it necessary to take special precautions in order to be able to determine an accurate water resistivity (R,) value from the spontaneous potential (SP) curve. Core analysis has confirmed that, in addition to intergranular porosity, fracturing is present in several Misoa reservoirs. It has been oilfield practice to identify producible oil sands by movable oil plots and locally developed computer processed interpretation programs. However, production logging results indicate that practically ali hydrocarbon production is coming from only a few of the intervals that had been interpreted from log analysis as oil-bearing. This paper attempts to answer some of the questions concerning the above mentioned difficulties. Production logging results are shown to support the conclusions. Résumé. Dans ce travail, on décrit l'évaluation pétrophysique de plusieurs puits du gisement de Motatán, situé dans les contreforts des Andes, dans l'Ouest du Venezuela. La production d'hydrocarbures provient de plusieurs sables de I'Eocène, à des profondeurs de 2440 à 3650 m. Les sables ont une porosité et une perméabilité faibles. L'évaluation précise des caractères prétrophysiques de ces sables a toujours présenté de grandes difficultés quant on doit faire des prévisions de production. L'absence d'horizons aquifères et l'existence d'un potentiel d'électrofiltration appréciable obligent à prendre des précautions spéciales, pour pouvoir déterminer avec précision la valeur de R, a partir de la courbe de PS. Les analyses de carottes ont confirmé, qu'en plus de la porosité intergranulaire, la porosité de fracture existe dans plusieurs des réservoirs de Motatán. Dans la pratique, les courbes de mobilité d'huile et des programmes d'évaluation sur ordinateur developpés localement ont été employés pour identifier les sables producteurs d'huile. Cependant, les résultats des diagraphies de production montrent que presque tout le pétrole produit vient de quelques-uns des intervalles interprétés a partir de i'ánalyse des diagraphies électriques comme contenant de huile. 1. INTRODUCTION The Motatán field is the southemmost of a chain of oil fiel
Abstract. Increasing world demand for oil and gas will provide the incentive to improve recovery efficiencies, exploit marginal reserves, and explore in more hostile environments. Concurrently, the explosive increase in data acquisition, telemetering, processing, and transmission capabilities will continue. These economic and technical changes provide challenges in reservoir petrophysical-measurement acquisition, handling, and integration. Individual well evaluation and analysis will increasingly be done at wellsite by truck-mounted computers. Future off-wellsite processing emphasis will concentrate on field studies, definition of input-data and answer accuracy. More difficult evaluation environments will exist, both in the search for new hydrocarbons and in the monitoring of production. Fresh-water floods and exotic tertiary flood fluids will require devices sensitive to parameters other than salinity. Expansion of logging capabilities in hostile temperature, pressure and corrosive-fluid environments will continue. A paramount need is for thorough evaluation of the microstructure of the reservoir rock and of the macrostructure of the reservoir unit. Better insight into the petrophysics of the reservoir and its production potential and behaviour is obtainable through an integration of welllog data and computer-processed interpretations with core data, pressure measurements, geological knowledge, and reservoir-modeling technique. Résumé. La demande croissante en hydrocarbures incitera à améliorer les rendements de récupération, à exploiter des réserves marginales et à prospecter dans des environnements plus hostiles. Parallèlement, les moyens d'acquisition des données de traitement, de télémétrie, et de transmission des données continueront leur croissance explosive. Ces évolutions, économiques et techniques, lancent un nouveau défi aux méthodes d'acquisition, de manipulation et d'intégration des mesures pétrophysiques de réservoirs. Sur le sondage même, l'interprétation par ordinateur transportable se généralisera. Les études de gisements et l'évaluation de la précision des données d'entrée et de sortie seront faites en centres de calcul. Des conditions d'évaluation plus difficiles se présenteront, autant dans la recherche de nouveaux gisements que dans le contrôle de la production. Des dispositifs sensibles à d'autres paramètres que la salinité seront rendus nécessaires pour suivre l'évolution des systèmes de récupération utilisant de l'eau douce ou des fluides spéciaux. L'extension des possibilités de mesures diagraphiques dans des environnements à haute pression, de fluides corrosifs et dans des recupératures hostiles continuera. Un besoin essentiel est l'évalu
- Geophysics > Borehole Geophysics (1.00)
- Geophysics > Seismic Surveying > Seismic Processing (0.46)
Abstract. Complex reservoirs offer ambiguities in mineralogy, deposition, fracturing, pore size and distribution or in the choice of variables used in weil log analysis equations. The computer makes possible the normalizing, recalibrating, shifting, merging, and the weighting of log data. Data from core analysis, drill stem tests, geological and reservoir engineering studies may be used to supplement the normal weil logs. The reservoir ambiguities may be identified and defined, using computer histograms and cross-plots. Repetitive analysis using a range of values for each variable can be employed until a preponderance of evidence points to one conclusion. Special weil logging programs, core analysis and computer programs can then be designed to obtain reliable reservoir data. Computer program concepts are similar regardless of the complexity of the machine and whether the input data is on magnetic tape or punch cards. Computer analysis techniques and procedures used in several types of complex reservoirs will be discussed. Résumé. Les réservoirs complexes présentent des ambiguités sur la minéralogie, la sédimentation, les systèmes de fractures, la distribution et la taille de pores ou sur le choix des variables utilisées dans les équations d'analyse des diagraphies. Grâce à l'ordinateur, il est possible de normaliser le recalibrage, le recalage, la reunion et la pondération les données. Les résultats des analyses de carottes et des essais aux tiges, les etudes géologiques et de réservoir peuvent être utilisées en complément des diagraphies électriques. Les ambiguités du réservoir peuvent être résolues à l'aide d'histogrammes et de cross-plots tracés par ordinateur. Des analyses peuvent être effectuées de manière répétitive, en affectant à chaque variable une gamme de valeurs, jusqu'à ce qu'une convergence d'indications permette de tirer une conclusion. Des programmes spécifiques d'analyse et de traitement de diagraphies peuvent alors être élaborés pour obtenir des caractéristiques de réservoir fiables. Les concepts qui régissent l'élaboration des programmes sont similaires, indépendamment de la complexité de l'appareil et de la maniere dont les données sont enregistrées. Les techniques d'analyse par ordinateur et les procédures utilisées dans plusieurs types de réservoirs complexes seront discutées. 1. INTRODUCTION Oil and gas reservoirs vary in lithology, mineralogy, depositional environment and fracturing, and as a result, there are ambiguities in the variables used in log analysis equations. The large storage capacity and the flexibility of the output make the computer a valuable tool for solving these problems. This paper is concerned with practical problems involved in the selection, prepar
- North America > United States > Louisiana (0.68)
- North America > United States > Wyoming (0.46)
- North America > United States > Alaska > North Slope Borough (0.28)
- North America > United States > Wyoming > Rozet Field (0.99)
- North America > United States > Wyoming > Laramie Basin > Niobrara Formation (0.99)
- North America > United States > New Mexico > San Juan Basin > Horseshoe Gallup Field (0.99)
- (7 more...)
PD 9(2) Wire Line Formation Sampling at Selected Depths in the USSR Oil Fields
Zhuvagin, I. G. (The All Union Research Logging Institute, Ufa, USSR) | Brodsky, P. A. (The All Union Research Institute of Logging Investigations, Kalinin USSR) | Grigoryan, N. G. (The All Union Research Geophysical Institute, Ramenskoye, USSR)
Abstract. Wire line formation testing and sidewall sampling have been improved to cope with more complicated conditions of well prospecting, more complex data interpretation techniques and new logging methods through the creation of improved apparatus. Wire line formation testers cutting multiple cores within limits of 200°C and 150 MPa determine formation productivity and provide more precise interpretation criteria. A new technique of well log investigation by multiple recoveries of fluids and the recording of pressure curves in 20 to 25 intervals per sampler trip has been developed. It allows the study of formation pressure, permeability and productive thickness. Wire line formation testers, for cased and uncased wells, capable of pumping vast amounts of formation fluids are being developed. In depths up to 5 km, boring core sampling devices are widely used. Efficiency is as great as ten undisturbed cores per trip. Cores are 25 mm diameter. A core sampler is in use with disk cutters taking five prismatic specimens 600 mm long. Coreguns permit taking thirty rock samples per trip in hardness up to 1500 MPa and in depths up to 7 or 8 km. Methods of analyzing these samples for reservoir quality have been developed. Résumé. Les conditions plus difficiles de l'exploration, les techniques plus complexes d'interprétation des données et de nouvelles méthodes de diagraphie ont entraîné l'amélioration des méthodes d'essais de couche et de carottage latéral par la mise au point d'outils à câble améliorés: des outils d'essais de formation prenant des carottes multiples jusqu'à 200°C et 150 MPa qui donnent la productivité de la couche et de meilleurs critères d'interprétation; une nouvelle technique de diagraphie par prélèvement multiple de fluide et enregistrement des courbes de pression dans 20 à 25 intervalles par descente, ce qui permit I'etude de la pression de formation, de la perméabilité et de la zone payante; des outils d'essai de formation pour trous ouverts ou tubés, assurant le pompage de grosses quantités de fluide; des carottiers par fraisage, fonctionnant jusqu'à 5000 m, et permettant de prélever jusqu'à dix carottes par descente, avec récupération totale. Les carottes ont 25 mm de diamètre; un carottier à disque prélevant 5 échantillons prismatiques de 600 mm de long; des carottiers à balles prenant 30 échantillons par descente jusqu'à 1500 MPa de dureté et 7-8 km de profondeur. Des méthodes d'analyse de ces échantillons pour déterminer les caractéristiques du réservoir ont été mises au point. Methods of wire line sidewall fluid and rock sampling were
A. A. HASSAN, M. E. HRISKEVITCH and others, referring to Papers 1 and 4 asked about the training or retraining of the log analyst or petrophysicist to the requisite level for the performance of such sophisticated work. They mentioned the skill needed in merging geology, geophysics, petrophysics, reservoir engineering, mathematics, statistical analysis and computer usage. Dr KASHIK, in reply, agreed that a highly qualified specialist is required because the principles involved lie at the merging point between seismic prospecting and well log analysis. However, he believes the traditional log analyst can acquire rather quickly the additional experience and expertise in special training centres. Dr DOBRYNIN, speaking as an educator, described the making of a well logging and geophysical prospecting engineer in the USSR. He developed his theme on the following main points: five years of study in University or Institute following high school, half this time on the fundamentals such as physics, chemistry, mathematics, computers, thermodynamics and so on, in addition to geology, petrophysics, geophysics, production engineering etc. summer field practise in the working place each year until graduation, after graduation a further year under the patronage of the Institute as a specialist prolonging the educational process. Dr GOUILLOUD, later, stated that the desired retraining or recycling of log analysts is feasible. J. T. C. HAY and GEORGE STOSUR asked about the reliability and advantages of the boring core slicer, described in Paper2. MrBRODSKY replied that approximately '95% of the attempted operations are successful, but very good preparation of the apparatus is required. Consolidated limestones must be permeable if they are to be cored. More cores are taken if numerous inhomogeneities or fractures are expected. The advantage of the coring tool over the side wall sampling gun is that it does not alter the rock structure. JOHN A. DOWNING'S enquiry about the expense and risk involved in running numerous wire line pressure tests (Papers 1 and 2) was answered by Mr BRODSKY. He said that the testing of, say, 20-25 intervals for pressure at a depth of 3000 m might require only 1.5- 2.0 h but that, obviously, this should not be done on every well. The usage pertains mainly to exploration wells where it is necessary to study the hydrodynamics of the section and to determine the effective thicknesses of many layers. In production wells it is useful for studying the results of water injection through a multiple layer situation. A. S. ABDINE asked Mr SALISCH why methods such as those described in Paper 2 were not used in the Venezuelan fields of Paper 5. Mr SALISCH pointed out that with its high sulphur content the oil was not very commercial a few years ago, so that logging and testing wer
- North America > Canada > Alberta (0.17)
- Europe > Netherlands > South Holland (0.15)
- Asia > Middle East > Iran (0.15)
Abstract. Defining oil pool limits implies exact knowledge of pool boundaries in three dimensions and vertical and lateral variations of petrophysical characteristics. The problem is solved in the course of field development through continuous evaluation of log data, well testing and core sample analysis. Early exploratory wells cannot provide enough input data for the existing system of algorithms (programs) for computer processing of borehole data. As drilling operations increase, petrophysical characteristics are better defined through geological and drilling data and refined evaluation techniques. This allows more comprehensive formation evaluation. Once exploration is complete, digitized well logs are re-evaluated for maximum information, including oil reserves. Effective thickness, porosity, shaliness, permeability, saturation and other parameters are presented as contour maps for the whole pool or its parts. Mapping algorithms should be flexible. The use of various apriori information makes possible more reliable regional parameter distributions and solves various geologic problems. For example, to determine the most dangerous breakthrough zones, porosity and permeability maps can be used which take into account the direction of the fresh water front movement. Résumé. La caractérisation des gisements pétroliers nécessite la connaissance précise de leur extension spatiale ainsi que des variations verticales et latérales de leurs propriétés pétrophysiques, obtenue par l'évaluation continue pendant l'exploitation, des données de diagraphies, essais et carottes. Les premiers puits d'exploration ne fournissent pas assez de données pour les programmes existants de traitement par ordinateur. Au cours des travaux de forage de développement, la connaissance des caractéristiques pétrophysiques s'améliore grâce aux données géologiques et de forage supplémentaires, et à des méthodes d'évaluation plus fines. Une fois l'exploration terminée, les diagraphies traitées numériquement sont réinterprétées pour en tirer le maximum d'informations, en particulier sur les réserves. La zone payaute, la porosité, l'argilosité, la perméabilité, la saturation et les autres paramètres sont présentés sous forme de cartes d'isovaleurs pour le gisement entier ou pour ses différentes parties. Les algorithmes de cartographie doivent être souples. L'utilisation des informations disponibles antérieurement, permet de construire des distributions de paramètres plus réalistes et de résoudre des problèmes géologiques divers. Pars exemple, pour déterminer les zones de percée les plus dangéreuses, on peut utiliser des cartes d
- Geology > Rock Type > Sedimentary Rock (0.48)
- Geology > Geological Subdiscipline > Economic Geology > Petroleum Geology (0.35)
- Geophysics > Borehole Geophysics (1.00)
- Geophysics > Seismic Surveying > Seismic Processing (0.47)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Exploration, development, structural geology (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Open hole/cased hole log analysis (1.00)
In his introduction the CHAIRMAN pointed out that the papers presented were chosen so as to cover a wide range of reservoir engineering topics and can be grouped as follows. The first two papers are primarily concerned with investigations aimed at a more reliable characterization of the reservoir. The next two papers deal with methods for improving the interpretation and prediction of reservoir performance. The fifth paper highlights continuing efforts to increase our limited oil reserves. The first paper, on the use of advanced seismic techniques in field development, was presented by F. R. VAN VEEN. In answering questions from MR NEDERLOF (Shell Netherlands) regarding the resolving power of this technique under various conditions, Mr VAN VEEN explained that as a general rule, below 3000 m it becomes difficult to distinguish between gas and liquid, because the acoustic impedance characteristics of the pore fluid is overshadowed by those of the matrix and because the density contrast becomes small. Thus, distinguishing oil from water is even more difficult. Also, reservoir fluids are less easily recognized in carbonate reservoirs because there the grain-to-grain contacts are better and thus the acoustic velocity depends to a lesser degree on pore fill than is the case for sandstone reservoirs. In reply to a question from Mr DOBRE (Research Institute for Oil and Gas, Romania) it was stated that resistivity logs had been used only to determine the gas saturation, which, in turn, is required to correct both the density and sonic log readings to ‘virgin-formation’ conditions before calculating acoustic impedance. The second paper, on displacement experiments at reservoir conditions, was presented by L. CUIEC. This presentation gave rise to a lively discussion on the subject of wettability. Answering questions from Messrs DIMITRI (Research Institute for Oil and Gas, Romania) and BI- LARDO (University of Rome), Mr CUEIC stated that the data available did not permit a conclusion with respect to wettability variation within a given reservoir. In his opinion the best wettability measurements are those based on imbibition and capillary pressure. Of these two, the imbibition method is the easier one. The contact angle method is less suitable and the thermodynamic method is not feasible with rock-fluid systems. No attempts had been made to compare methods. Mr OFFERINGA (Shell Research, Netherlands) noted that wettability measurements had been carried out under normal pressure and temperature and questioned to what extent the results obtained are representative of the wettability of cores saturated and aged under reservoir conditions, bearing in mind e.g. that a decrease in pressure may lead to deposition of asphalte
- North America > United States (0.95)
- Europe > Netherlands (0.71)
- Geophysics > Seismic Surveying (0.68)
- Geophysics > Borehole Geophysics (0.54)
- North America > United States > Mississippi > Improve Field (0.99)
- Europe > Netherlands > North Sea > Dutch Sector > Schoonebeek Field > Bentheim Sandstone Formation (0.99)
The Chairman in his introductory remarks said that it had proven to be very difficult to compress into the span of five relatively brief papers the spectrum of activities embodied in the title ‘Development in Production Systems for Deep Water’. This was particularly true in view of the wide range of subject titles of papers suggested by the national organizations. In making their selection, the Committee had concentrated on covering as broad a spread of subject matter as possible and had attempted to strike a balance between papers which essentially were reviews of the ‘state of the art’ and others which covered topics already in field application and could, therefore, provide some actual operating experience. He said that, ‘deep water’, being a relative term, for some might bring to mind depths in the 150-200 m range, while for others it would certainly now have a significance of 300 m or more. The Committee had placed emphasis on those systems which they believed had the scope for application in progressively deeper waters and had chosen examples of both fixed and flexible structures, sub-sea production systems and floating production systems for general review. They had selected the particular example of the Grondin field sub-sea production system because this appeared to be one of the most advanced in field application, and then had finished their selection with what must surely be the largest scale application to date of a deep water production systemthe Statfjord Field. The Chairman then announced that it was the intention to have a question period immediately after each paper, as it was felt that this would provide a means of ensuring that there was well balanced discussion on all the topics. L. W. WELCH (Exxon, USA), the First Vice-Chairman of the Panel, began the questions on the first paper (Deep-Water Platforms) by stating that ‘the literature has described several alternative structures to pilefounded platforms for deepwater use, and you have discussed one in some detail. Yet, none of the alternatives has been installed for production operations. What has limited their introduction into field use?’ In reply, Mr BRANNON pointed out that field use of a new type of structure required that the new structure show, for the specific case under review, a marked advantage over a conventional platform, both economically and structurally. Such advantages apparently have not been shown for fields developed to date. Also, in comparing new structures with conventional pile-founded platforms, appreciable weight in the assessment will undoubtedly be given to the long history of satisfactory experience with conventional structures. Mr WELCH also asked Mr BRANNON what he expected to be the water-depth limits for platform installations, and what are the m
- Europe > United Kingdom > North Sea > Northern North Sea (0.34)
- Europe > Norway > North Sea > Northern North Sea (0.34)
- Collection (0.41)
- Research Report (0.34)
- North America > United States > California > North Pacific Ocean > Santa Barbara Channel > Santa Barbara-Ventura Basin > Santa Ynez Unit > P0791 > Hondo Field (0.99)
- North America > United States > California > North Pacific Ocean > Santa Barbara Channel > Santa Barbara-Ventura Basin > Santa Ynez Unit > P0161 > Hondo Field (0.99)
- North America > United States > California > North Pacific Ocean > Santa Barbara Channel > Santa Barbara-Ventura Basin > Santa Ynez Unit > P-0191 > Hondo Field (0.99)
- (9 more...)