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Abstract. During the past decade, extremely positive results have been obtained by an Elf operated Group in Block 3, Offshore Angola. This block, located within the southern part of the Lower Congo Basin, was awarded in 1980 and previous to that date, only one well had been drilled to test the Tertiary objectives. Since then, 40 exploration wells have been drilled resulting into 22 discoveries. Proved reserves exceed 160 x lo6 m3 (1 billion bbl) of recoverable oil; all reserves discovered to date are associated with the Pinda Carbonate Reservoir of Albian Age. This successful exploration has occurred because of a step by step multi-disciplinary approach that incorporated long experience in West Africa, particularly in relation to turtle-back structures associated with salt tectonics, detailed sedimentology, sequence stratigraphy, geochemistry and 3D seismic interpretations; these seismic interpretations are completed using a powerful work station: SISMAGE. The results of the technical evaluation are: more accurate prospect delineation and a better reservoir character prediction. Gravity sliding concept and moclelization clearly explain the paleogeography of the prolific Albian reservoirs and the tectonic history of the Pinda structures resulting from โraftingโ and halokynesis. 3D seismic has significantly improved the definition of trap geometry. Present efforts are focused on resolving imaging problems caused by tectonic complexity (dips, faults, collapses) and seismic velocity anomalies related with lithologic facies variations and/or diagenetic events. 1. GEOLOGICAL SETTING Angola Block 3 is located in the southern part of the Congo basin. This Basin extends over 600 km between latitudes 3" and 8" south and includes parts of Angola, Congo and Zaire. The geological history of the basin can be divided into three major phases: a rift phase, an evaporitic period and an oceanic expansion phase. The final phase can, in turn, be divided into two major sequenes-a transgressive sequence (Albian-Pa1eocene)-followed by a regressive sequence (Eocene-present time). The rift phase started 140 million years B.P. during the Early Cretaceous. The Sediments which were deposited during this rift phase are called the pre-salt series. The evaporitic period extended from 110 to 105 million years B.P. Salt deposits, for which the original thickness is assumed to have reached loo0 m are responsible for the formation of the Albian structures. Block 3, which encompasses over 3600 km2 offshore is located in water depths ranging from 40 m in the eastern to about 300 m in the western part of the block. The main objectives within the blocks include mainly Tertiary sandstones in the western part of the block and the pre-salt and post salt series on the Albian platform are
- Geology > Structural Geology > Tectonics > Salt Tectonics (1.00)
- Geology > Geological Subdiscipline (1.00)
- Geophysics > Seismic Surveying > Surface Seismic Acquisition (0.72)
- Geophysics > Seismic Surveying > Seismic Interpretation (0.46)
- Africa > Angola > South Atlantic Ocean > Lower Congo Basin > Area B > Block 0 > Greater Vanza Longui Area (GVLA) Field > Pinda Formation (0.99)
- Africa > Angola > South Atlantic Ocean > Congo Basin (0.99)
- Africa > Angola > South Atlantic Ocean > Lower Congo Basin > Block 3/05 > Pacassa Field (0.89)
- (2 more...)
Abstract. The prolific Mahakam Delta province (Kutei basin, East Kalimantan) had reached a high degree of maturity (first oil in 1898) when a major effort of regional synthesis, aimed at identifying by-passed stratigraphic traps, was initiated. It was followed by an aggressive exploration program which led to the discovery of the giant Peciko gas field. The approach involved the establishment of a precise regional chronostratigraphic correlation framework and the detailed study of basin dynamics. Deep pay zones in the Mahakam are characterized by a monotonous stacking of deltaic cycles featuring a very constant, commonly delta-front depositional environment, with marine flooding episodes expressed as areally extensive shaly intervals. Individual sand bodies are thin and numerous with multiple fluid contacts, and detailed correlations are highly problematic. An original migration and entrapment model where the hydrocarbon column is considerably enhanced by hydrodynamic conditions was proposed and calibrated by an innovative well data acquisition program. Landwards directed groundwater circulation driven by overpressured shales, located laterally to the reservoirs, was evidenced from pressure measurements. Lateral communications and effective vertical seals at the field scale were successfully recognized using pressure data; hydrocarbon columns were measured and tilted contacts were mapped systematically in the course of the 12 well appraisal campaign. The proposed model helped a lot in the swift delineation of the field, initially described as โstratigraphicโ. 1. INTRODUCTION Encountering hydrocarbons in a stratigraphic play leads to a new orientation of exploration thinking. Firstly, well results frequently differ from expectations and secondly, even after the drilling of several more wells, answers to the basic question remain elusive: - What is the likelihood that it may be turned into an economic resource? This question is of course common to all discoveries, but it is much more strongly felt for stratigraphic plays where discontinuous reservoirs and uneven hydrocarbon fill are often implied in the play concept itself. It is especially true in deltaic petroleum provinces like the Mahakam Delta (East Kalimantan, Indonesia) where individual sand bodies are thin and numerous, with multiple fluid contacts and unreliable correlations. The Peciko field provides a striking example of the beneficial use of two combined evaluation techniques to achieve more convincing extrapolations of well results during the evaluation process:โan extensive regional synthesis study integrating a basin dynamics perspective; โa systematic reservoir pressure data acquisition program. This paper presents with posters a resume of the history of the field&
- Geology > Geological Subdiscipline > Stratigraphy (1.00)
- Geology > Sedimentary Geology > Depositional Environment > Transitional Environment > Deltaic Environment (0.92)
- Geology > Petroleum Play Type > Conventional Play > Stratigraphic Play (0.76)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (0.38)
- Asia > Indonesia > East Kalimantan > Makassar Strait > Kutei Basin > Mahakam Block > Peciko Field (0.99)
- Asia > Indonesia > East Kalimantan > Makassar Strait > Kutei Basin > Mahakam Block > Mahakam Field (0.97)
Abstract. Of the vast Russian oil resources, only one third is explored. A decline in production since 1987 has resulted not from reserve depletion, but from the general economic crisis and the deterioration of reserve quality, expressed in reduced flow rates due to the depletion of the largest fields, increase in water cut, decline in the size and productivity of new discoveries. Undiscovered oil resources of Russia account for 85-90% of the total former USSR resources, outstripping any other country but ranking below the joint resources of the Middle East countries. Most of the unexplored oil resources are concentrated in West Siberia, Arctic and Pacific sea shelf and East Siberia. Russian oil legislation is regulated by the Law on Subsurface Resources, Regulations of Exploration and Production Licensing and draft Law on Oil and Gas. The Law provides for exploration and production licensing on a โtwo keysโ basis, the license awards and terms settlement being executed jointly by local and central authorities. An obligatory supplement to the license is the License Agreement concluded by licensing authorities and the rightholder. The terms of the License Agreement correspond to the world experience of oil business. The Law gives vast opportunities for the settlement of mutually acceptable terms when licenses are obtained by competition, at bidding rounds or by direct negotiations. Russia is one of the largest oil producers in the world with a long and complicated history of the petroleum industry. At the beginning of the century, Russia accounted for half of the total world oil production. In 1911 crude production for the first time peaked at 11.5 MMt. After a drastic drop to 3.7 MMt in 1918, oil production started to grow again, peaking for the second time at 34 MMt in 1940. During World War II, oil production dropped for the second time. In the post-war period oil production in the USSR continuously increased until 1984. In 1985, production dropped again, but during 1986โ1988 HC liquids production in Russia increased to 569.5 MMt, amounting to 624 MMt in the whole USSR. This was the third peak in the history of Russian oil industry. In recent years oil production showed a sustained decline. In 1993, oil and gas condensate production was about 355.4 MMt (Fig. 1). Is the third decline in oil production caused by depletion of oil resources? Or are there oil reserves sufficient to stabilize and increase oil production? And if so, what are the problems related to their development? The vast reserve base enabling Russia to be the world's leading oil producer was the result of exploratory efforts in West Siberia, Ural-Volga and other regions, performed mostly during 1950โ1980s. Exploration activity was the highest during the last 30 years. This peri
- Europe > Russia (1.00)
- Asia > Russia > Siberian Federal District (0.25)
- Asia > Russia > Ural Federal District > Khanty-Mansi Autonomous Okrug > West Siberian Basin > Central Basin > Samotlorskoye Field (0.99)
- North America > Canada > Quebec > Arctic Platform (0.95)
- North America > Canada > Nunavut > Arctic Platform (0.95)
- (2 more...)
Abstract. The Pliocene and Quaternary Ravenna Basin is the most prolific among the Italian gas basins even if its exploration has reached a mature stage, rate of success is very high and discovery of new fields continuing. Results are related to the application of the most updated geophysical and logging technologies. During 1990 it was fairly evident that available 2D seismic data, even if processed down to the attribute stages, had reached their limit when identifying new prospects. Basin evaluation, using statistical approaches, was indicating an acceptable amount of resources still to be discovered both in structurai and stratigraphic traps. A 3D survey was planned over an area of almost 13 000 sq km, the largest ever shot for exploration purposes. The job pian was put together with an industriai concept in order to reduce as much as possible both acquisition and processing costs while ensuring high final data quality. The work required a huge organizational effort and has been achieved using the most advanced acquisition and processing technologies. Examples of 3D data interpretation, integrated with pressure studies and structural analysis for tectonically complex prospects, and with sedimentology and log analysis when defining stratigraphic traps, are presented. 1. INTRODUCTION The Pliocene and Quaternary Ravenna clastic sedimentary basin covers both the eastern part of the Po valley and the northern Adriatic sea. It is the most prolific Italian gas province with a total number of 86 gas discoveries, 59 of which are offshore and have original reserves ranging from a maximum of 102 Gscm of gas to a minimum economical limit of 0.4 Gscm for fields down to 30 m of water depth. The Pliocene and Quaternary sequences are characterized by interbedded sands and shales; sands were deposited as widespread turbidites sheets in deep water conditions having a main northwestern source; shales, instead, constitute both the cap of the reservoirs and the source rock of the biogenic gas (Fig. 1). The trapping mechanism is of a structural and mixed structural and stratigraphic type. Structural traps were generated by the various pliocenic tectonic pulses having a northeasterly vergence; the mixed traps, instead, are partly related to tectonics, partly to unconformable onlap of sand bodies draping on morphological highs and being deposited over shales. The largest fields are of a multipool structural type with a four way dip closure. Up to now very few purely stratigraphic gas fields have been discovered. The front of the Apennine thrust belt is located in the south western sector of the basin, while the remaining part represents the foreland where stratigraphic t
- Europe > Italy (0.29)
- North America > United States (0.28)
- Phanerozoic > Cenozoic > Neogene > Pliocene (0.75)
- Phanerozoic > Cenozoic > Quaternary (0.66)
- Geology > Structural Geology (1.00)
- Geology > Geological Subdiscipline > Stratigraphy (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (0.96)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Geologic modeling (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Exploration, development, structural geology (1.00)
Abstract. In the mature Frigg/Heimdal area, located in Quadrant 25 in the Norwegian sector, ten discoveries have been made. Most of the area is covered by 3D. Such a dense database has proven favourable to multidisciplinary and Integrated approaches. The Integrated approach is the key to the evaluation of small petroleum accumulations at the Brent level in the area. The current geological model for the Brent Gp is based on High Resolution Sequence Stratigraphy, a method integrating a consistent biostratigrapical framework, coal petrography and coherent reservoir zonation and correlation. Improved techniques in organic geochemistry has enabled the definition of the origin of the reservoir hydrocarbons. Detailed well information including โDiamageโ (core/electric log correlation), VSP and Walkaway VSP is of indisputable importance for well/seismic calibration and the seismic interpretation. The detection of subtle structural and stratigraphical features by seismic horizon attribute displays has been implemented on the new generation of work stations-SISMAGE@', the meeting point to merge the results from the different geo-disciplines involved in the Integrated approach. The various approaches together with improved 3D acquisition and processing have demonstrated that they, in an integrated form, contribute not only to reduce the timeframe for the exploration/appraisaI/development phase but also to lower the risk. INTRO DUCTI0 N The FriggJHeimdal area, which bas reached a mature phase of exploration, is located in Quadrant 25 in the Norwegian sector of the North Sea (Fig. i) and consists of five blocks: 2511, 2512, 2513, 25/4 and 25/5, operated by Elf Petroleum Norge AIS. Since the allocation of the first blocks in 1969 (25/1 and 2) ten discoveries have been made. Most important are the Tertiary gas/condensate discoveries Frigg (183 billion Sm3 reserves) Heimdal (33 billion Sm3 reserves), North East Frigg and East Frigg made in the early seventies. They made up an important reserve basis (230 billion Sm3 of gas + condensate) on the Norwegian shelf. The main reservoirs are of Early Eocene to Early Paleocene and Middle Jurassic age. Most important are the Frigg Formation (Early Eocene) and Heimdal (Late Paleocene) sandstones being part of a complex Paleocene/Lower Eocene submarine fan, deposited in the axial part of the Viking Graben east of the structurally higher Shetland Platform. The Tertiary structures are mainly formed by the sub-marine fan depositional topography and enhanced by the draping and differential compaction of the sands. Some influence by differential Cenozoic subsidence occurs due to the fact that several of the fields are lying above deeply buried Jurassic highs.
- Europe > Norway > North Sea > Northern North Sea (0.67)
- Europe > United Kingdom > North Sea > Northern North Sea (0.49)
- Phanerozoic > Cenozoic > Paleogene > Paleocene (1.00)
- Phanerozoic > Cenozoic > Paleogene > Eocene > Ypresian (0.74)
- Phanerozoic > Cenozoic > Paleogene > Eocene > Lutetian (0.74)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (0.50)
- Geology > Structural Geology > Fault > Dip-Slip Fault > Normal Fault (0.34)
- Geology > Sedimentary Geology > Depositional Environment > Marine Environment (0.34)
- Geology > Geological Subdiscipline > Stratigraphy > Sequence Stratigraphy (0.34)
- Europe > United Kingdom > North Sea > Northern North Sea > Viking Graben > PL 030 > Frigg Formation (0.99)
- Europe > Norway > North Sea > Northern North Sea > South Viking Graben > PL 026 > Block 25/2 > NOAKA Project > Lille-Frigg Field > Brent Group Formation (0.99)
- Europe > Norway > North Sea > Northern North Sea > South Viking Graben > PL 024 > Block 25/1 > NOAKA Project > Frigg Field > Frigg Formation (0.99)
- (4 more...)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Near-well and vertical seismic profiles (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Geologic modeling (1.00)
[l]P5 New Petroleum Fields and Offshore Provinces in Russia
Khalimov, E. (Institute of Geology and Exploration of Combustible Fuels, Moscow) | Orudgeva, D. (Institute of Geology and Exploration of Combustible Fuels, Moscow) | Obukhov, A. (Institute of Geology and Exploration of Combustible Fuels, Moscow) | Lovelock, E. R. (Shell Internationale Petroleum Maatschappij, Netherlands)
Abstract. Russian sea shelves cover about 3.9 million sq. km (14% of total world area). The petroleum potential of the Russian shelves exceeds the hydrocarbon (HC) reserves of the North Sea more than tenfold. However, 82% of the HC resources of the Russian shelf are confined to the Arctic seas with an extremely severe environment (low temperatures, ice, high waves, storms and hurricanes, etc.). About 14% of the undiscovered resources lie in the Far East and 4%-in the Russian sectors of the Baltic and Caspian seas. Russian offshore HC resources are poorly developed. Oil reserves to resources ratio is about 1% in the Arctic seas and about 13% in the Far East seas. 30 oil and gas fields have been discovered and quite a few promising structures identified in the Russian sea shelves. Geologic structure and development conditions of the following fields are given in brief: Peschano-Ozerskoye (1982), Gulyayevskoye North (1986), Prirazlomnoye (1989) (the Barents Sea); Odoptu Offshore (1977), Chaivo Offshore (1979), Lunskoye Offshore (1984), Piltun-Astokhskoye (1986), Arkutun-Daginskoye (1989) (the Sea of Okhotsk). Oil discoveries are classified according to their commercial importance and development conditions. Oil production volume from new Russian offshore discoveries is forecasted. The importance of world experience, application of advanced technologies and up-to-date equipment for offshore oil exploration, production and drilling in Russia is evaluated. INTRODUCTION The total area of the offshore provinces of Russia including both the outer seas (Arctic and Far East) and the inner seas (Caspian, Baltic, Rlack Seas and Sea of Azov) amounts to nearly four million km2, or 14% of the world's shallow water offshore regions. The water depth at the edge of the shelves reaches 240 m while the width varies greatly from 5 up to 1350 km. Numerous depositional basins are to be found within this vast offshore area, of which the largest are as follows: - East Barents, South Kara, Laptev, East Siberian and Chukchi in the Arctic - Anadyr, Navarin, Khatyrka, Olyutorsk-Komandor, North Sakhalin, Okhotsk-Kamchatka and South Okhotsk in the Far East The oil and gas potential of Russia's offshore provinces is 6 times larger than that of the North Sea. However, 82% of its resources are located within the Arctic Seas which feature the most harsh climatic conditions (i.e. low temperatures, thick sea ice for most of the year, high waves and storm force winds etc.). The Far Eastern seas account for 14% of the potential resources while 4% is to be found in the Baltic, Caspian, Black Sea and Azov provinces. Most of the hydrocarbons remain undiscovered. So far only about 1% of the potential reserves in the A
- Europe > Russia > Northwestern Federal District > Nenets Autonomous Okrug (0.31)
- Europe > Russia > Northwestern Federal District > Komi Republic (0.31)
- Asia > Russia > Far Eastern Federal District > Sakhalin Oblast (0.28)
- Asia > Russia > Far Eastern Federal District > Chukotka Autonomous Okrug > Anadyr (0.25)
- Phanerozoic > Mesozoic > Cretaceous (0.51)
- Phanerozoic > Cenozoic > Neogene (0.49)
- North America > United States > Alaska > Bering Sea > Navarin Basin (0.99)
- Europe > Russia > Northwestern Federal District > Northwestern Federal District > Nenets Autonomous Okrug > Timan-Pechora Basin (0.99)
- Europe > Russia > Northwestern Federal District > Komi Republic > Nenets Autonomous Okrug > Timan-Pechora Basin (0.99)
- (31 more...)
Abstract. Statistical trends of discovered hydrocarbon volumes show an increasing dominance of established hydrocarbon basins as opposed to Frontier acreage. Nevertheless, new basins remain promising mainly for their potential volumetric upside and the high reward. Because of generally higher costs, it is imperative to improve the explorer's capacity to make better and more direct measurements, thereby increasing predictability and reducing risk. Even in Frontier situations, this involves a multidisciplinary approach. From the onset, information sampling must be guided by an integrai view of the potential field life. Professional input from mature hydrocarbon basins is necessary to apply relevant technology, obtain maximum benefit from new data sets and generate the best technical and economical models. As a result, basin-wide exploration has evolved from being mere โtreasure huntingโ to a much more sophisticated business involving professionals from a broad industry-wide range, a growing technical arsenal, and a more comprehensive approach. This evolution implies change in training and organization and its success is critically dependent on qualitative communication and data management. Examples will provide some insight into the way Shell manages the change. CURRENT STATE OF EXPLORATION In spite of concerns about the future of the oil industry, technological advances continue to allow substantial increases in hydrocarbon reserves. As a result, the world's proven oil reserves are now estimated to represent about 45 years' supply assuming current production levels, whereas in 1973, for instance, they were thought to be sufficient for 30 years' supply only. Although a number of new hydrocarbon provinces have been established during the past decade (Fig. i), their contribution to the total volumes of hydrocarbons discovered is modest. There is an increasing dominance of new discoveries in established hydrocarbon provinces over those in frontier acreage. This is in marked contrast to the 1960s and early 1970s when many very large fields were discovered in new provinces like the North Sea and Alaska, and reserves increases were largely driven by frontier exploration. Looking back, the wave of frontier successes in the 60s and early 70s can be seen as having been underpinned by three things; the industry's newly developed technological ability to explore the offshore continental shelves, significant improvements in super-regional geological knowledge and the effectiveness of worldwide exploration โcreamingโ through the use of digital seismic. These factors were closely interrelated and their beneficial effect on exploration allowed new frontiers to temporarily dominate the scene. The technologial advances of the 80s h
- North America > United States > Alaska (0.24)
- Europe > United Kingdom > North Sea (0.24)
- Europe > Norway > North Sea (0.24)
- (2 more...)
- Geology > Geological Subdiscipline > Stratigraphy (1.00)
- Geology > Rock Type (0.94)
Abstract. Today's exploration for hydrocarbon traps is, in many areas, characterized by smaller discoveries in subtle traps-perhaps in previously unexplored geological formations. At the same time, an increased pressure to minimize time from discovery to production is experienced, and the need for optimal utilization of all field related information is becoming increasingly obvious. This calls for accurate geometric and palinspastic basin descriptions on all scales and at any time from deposition up to the present. In this presentation a dynamic basin model is described, which is designed to utilize all available data at all scales, and to serve as one modelling tool from exploration to reservoir studies. This challenge calls for the utilization of optimal data bases together with geological, as well as geophysical modelling and reservoir simulation tools. The core of- the concept is a 3-dimensional data model. The model must be developed to include basic geological and geophysical data as obtained in the earliest exploration stage, with the ability of being โinfinitelyโ expanded over the life-time of the field. Accordingly, such a model must be built on the best modern technology to obtain necessary solidity, long life and flexibility. The data base is regarded as a core in a cluster of geophysical, geological and reservoir modelling tools. It is expected that such tools will undergo an enormous development in the near future. This demands that the central data base as well as the modelling tools are built by common standards, so that new versions and new tools can easily be incorporated. 1. INTRODUCTION Although new areas still are to be opened, the number of mature hydrocarbon provinces which are available for hydrocarbon exploration is decreasing. Combined with a pronounced pressure to explore with less cost and to exploit existing reserves more efficiently, this challenges the oil companies to better utilize their resources in terms of personnel, data, interpretation and simulation techniques. In mature areas the larger fields have already been explored, and only smaller discoveries, maybe in the form of subtle traps, in less favourable and less known formations, remain to be found. At the same time, there is pressure to minimize the time from discovery to production, and the need for optimal utilization of all relevant geological and geophysical information is becoming increasingly obvious. This calls for accurate geometric and palinspastic basin descriptions on all scales at any time in the basin history. Centrally in meeting these challenges lies optimal data bases which are accessible for geophysical and geological modelling, as well as production simulation. Through times of exploration and production oil companies have accumulated enormous amounts of geophysical, geologi
- Europe > United Kingdom (0.47)
- Europe > Norway > North Sea (0.29)
- Geology > Structural Geology > Fault (1.00)
- Geology > Sedimentary Basin (1.00)
- Geology > Structural Geology > Tectonics (0.69)
- Geology > Geological Subdiscipline > Geochemistry (0.68)
- Geophysics > Seismic Surveying > Seismic Modeling (0.89)
- Geophysics > Seismic Surveying > Surface Seismic Acquisition (0.68)
- Geophysics > Seismic Surveying > Seismic Processing > Seismic Migration (0.46)
- Geophysics > Seismic Surveying > Passive Seismic Surveying > Earthquake Seismology (0.46)
Abstract. The classification of resources, both undiscovered and discovered, is becoming increasingly important in the decision making process of major oil companies. Statoil has developed a new internal resource classification system to support investment decisions and the management of petroleum assets. To achieve this goal, resource definitions have been related to the value chain from early exploration to production, and to economic assessments. Each resource class is associated with a typical business action. Both undiscovered and discovered resources are included, with the discovered, undeveloped petroleum assets given a major focus due to their importance in resource management. The use of the classification system increases the awareness of the quality and consistency of the resource calculations and of the registration of discovered resources. A method of analysing prospects and discoveries according to their different geological segments (fault blocks etc.) has been chosen to achieve a consistent resource assessment. This reduces the possibility of unexpected results, causing significant reductions in the recorded discovered resources. The estimates of resources are made using probability distributions. In this way the summation of resources by the use of Monte Carlo simulation, is a fast operation and the variance can be estimated. The proven reserves, which we define as a โlowโ value with a high degree of certainty (90-percentile), are easy to calculate both within individual fields and for aggregated reserves of many fields. 1. INTRODUCTION A resource classification should identify those resource types necessary for developing a company's strategy. The optimal basis for decisions is obtained by classifying the resources according to the importance of the decisions to be made. The resource classification is also a kind of โresource accountingโ where one can highlight reserves used to write off field investments, well investments and the resource figures to be quoted in the company's annual reports. To enable decision makers to act on the best and most correct basis, it is essential that the resource accounting is founded on a well defined classification system. In the past Statoil has used a modified version of the resource classification system developed by McKelvey, 1975 (Fig. 1). The diagram has one axis representing increased geological assurance (moving from undiscovered to discovered resources), and the other axis representing increased economic feasibility. In this way the two fundamental aspects of our business are well illustrated. However S
Abstract. The occurrence and quantity of world petroleum resources appears to be well understood. The numbers are so great, however, that even minor variants in the total picture can be responsible for enormous localized industrial activity. Specific knowledge of the widespread local occurrences of oil and gas, therefore, is important to economic development and to the free market distribution of energy. It is also clear, however, that a large proportion of the recoverable petroleum resources are found in only a few selected localities. We believe that, worldwide, recoverable conventional oil and gas exist in ultimate quantities approximating 2300 billion barrels (370 Gm3) of oil and 12 O00 trillion cubic feet (340 Tm3) of gas. These values are limited by our concepts of world petroleum geology and our understanding of specific basins; nonetheless, continued expansion of exploration activity, around the world, has resulted in only minimal adjustments to our quantitative understanding of ultimate resources. Reserves reporting has been one of the greatest hindrances to a thorough understanding of world resources because we are just now gaining an understanding of field growth and what is actually being calculated and reported from various localities. Unconventional resources are present in large quantities, in particular in the Western Hemisphere, and are of a dimension to substantially contribute to world reserves should economic conditions permit. 1. INTRODUCTION AND DEFINITIONS World Ultimate Resources of conventional crude oil and natural gas remain interpreted as being about 2300 billion barrels (370 Gm3) of oil (BBO) and 12000 trillion cubic feet (TCF) (340 Tm3) of gas. These two values are approximately equal in energy. Some researchers have considered that the 12000 TCF value most certainly is low because source opportunities for gas are so much greater than for oil including the thermal conversion from oil to gas. Mindful of this, we have tried to increase gas resource values, but considering the sensitivity of gas entrapment to sealing rocks and faulting, it has been difficult to determine from where greatly increased values might derive. Unconventional resources, such as extra heavy oils, tar sands, gas in tight sands, and coal bed methane are not herein considered but they must, nonetheless, be recognized as being present in very large quantities. They are, however, expensive to recover at adequate rates of production, and sometimes expensive to alter to the quality necessary for modern day use. We don't know how, if, or when they will become major components of world energy consumption but certainly their development must be tracked carefully for signs of economic life or political/economic preference. The two major sources of unconventional oil, most rec
- South America (1.00)
- North America > United States (1.00)
- Europe (1.00)
- (3 more...)
- Geology > Rock Type > Sedimentary Rock (0.88)
- Geology > Petroleum Play Type > Unconventional Play > Heavy Oil Play (0.68)
- Geology > Structural Geology > Tectonics (0.68)
- Geology > Geological Subdiscipline > Economic Geology > Petroleum Geology (0.67)
- Government > Regional Government > North America Government > United States Government (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- South America > Brazil > Campos Basin (0.99)
- North America > Canada > Saskatchewan > Western Canada Sedimentary Basin > Alberta Basin (0.99)
- North America > Canada > Northwest Territories > Western Canada Sedimentary Basin > Alberta Basin (0.99)
- (17 more...)
- Reservoir Description and Dynamics > Reservoir Characterization > Exploration, development, structural geology (1.00)
- Management > Asset and Portfolio Management > Reserves replacement, booking and auditing (1.00)
- Reservoir Description and Dynamics > Reserves Evaluation > Reserves classification (0.95)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Coal seam gas (0.88)