The characteristics of petroleum exploration are discussed here with historical sense and schematic view, in order to understand scientific and technological nature of exploration. On the basis of such understandings, this paper discusses how modern explorationists can seek a clue of new technological development, when they intend to know what to do promptly for the future successful and expandable exploration.
First of all, they had better review remaining questionable points and re-examine unsolved problems in the past “normal exploration,” with having doubts about previous interpretations, and with their close and careful attention. Such actions should be just the studies called “extraordinary exploration,” and those may be a trigger to lead important logic creation to be called “exploration revolution.”
As the second action, unconventional exploration must be conducted with wide variety. The exploration of so-called unconventional type of resources such as natural gas hydrates or hydrocarbon from tight reservoirs and so on may not be based yet upon a completed scientific theory. Process to construct new theory replacing or standing in a line to the ongoing paradigm of petroleum exploration, however, may be the action that is appropriate to be described an “exploration revolution.”
The third of what the explorationists should do is to conduct “normal exploration” itself continuously. The expansion of the objectives of conventional exploration is a driving force to pull innovation in the technology of drilling and production, and leading factor of maturity of exploration. Maturation of normal exploration with a recent paradigm will encourage an outbreak of following exploration revolutions through the occurrence of extraordinary explorations.
INPEX OFFSHORE NORTH WEST SABAH, LTD (INPEX) acquired an exploration right of block in deepwater offshore NW Borneo, Malaysia in 2012 and conducts exploration activities as an operator.
Large oil and gas fields have been discovered and developed in the Fold & Thrust Belt (FTB) in the deepwater NW Borneo. The Fold & Thrust Belts have been forming since Late Miocene, and in which exploration targets are Miocene to Pliocene deepwater turbidite sandstones. Assumed technical problems in the exploration work in this region are (1) uncertainty in interpretation of structural closure because of poor seismic image affected mainly by shallow gas or hydrate, located in its upper crest part, (2) distribution of turbidite sandstones in the Fold & Thrust Belt and (3) trapping mechanism which controls fluid type of fields. There remains an undrilled large anticlinal structure in the block because of geological risks mentioned above. INPEX is challenging to drill the structure solving these technical problems by applying the new high-end multi azimuth broadband 3D seismic technology.
New 3D seismic data achieved improved seismic data quality in bandwidth, S/N and deeper penetration and seismic images of fault surfaces and depositional facies. The seismic cube was used for the structural re-interpretation and the reservoir distribution study for finalizing the evaluation of drilling prospects and those locations. The geomorphological approach was applied to the reservoir intervals and depositional environment, sediment fairways and Net reservoir thickness/Gross interval map for those intervals were updated within the block which were integrated with regional geological understanding.
The post mortem analysis of upcoming drilling campaign should be incorporated for further understanding of regional petroleum system, trapping mechanism and sandstone distribution. The role of High-end 3D seismic will be more crucial to narrow the ranges of the geological uncertainties of undrilled structures and to make them possible drillable prospects in matured basin.
JAPEX and Mitsubishi Corporation jointly acquired an indirect 50% working interest in the Kangean PSC Block in 2007, and are actively conducting the exploration, development and production of the block through the operating company Kangean Energy Indonesia Ltd. (KEI). The block has a diverse inventor y comprising producing fields, an undeveloped discovered field, numerous prospects and leads. The structural geology of the Kangean area is essentially the same as the East Java and Madura Island area to the west, and is divided into three provinces, Northern Platform, Central High and Southern Basin. The petroleum system is common to the East Java area; two petroleum systems have been identified. One is a thermogenic oil and gas system with Pre-Ngimbang and Ngimbang formation source rocks, and another is a biogenic dry gas system with methane accumulations in the shallow horizons.
After JAPEX and Mitsubishi entered the project, KEI has commenced the development of TSB (Terang, Sirasun and Batur) gas field. The Terang gas field has been developed as the Phase I development of TSB gas field, commenced production in May 2012 and produces around 300 MMscfd of gas.
Among the tasks for promising inventories that will be critical to sustain the development of the Kangean Block, the two projects will be technically interesting; one is the West Kangean appraisal drilling, and another is an exploration drilling of South Saubi prospect. The reservoir of the West Kangean gas field are fractured limestone of the Ngimbang formation, DFN (Discrete Fracture Network) geological model has been established, and reservoir simulation has been conducted to optimize the number and location of wells. The South Saubi Prospect is the largest structure in the Kangean Block inventory, and its play type (Reef buildup of Kujung limestone) is the same as the Banyu Urip oil field in East Java.
Activities by man-kind are limited in the Arctic, high latitude place more than North 66°33′, because of its hostile environment. Only military base, scientific observation station, resources production sites and ethnic community exist. Oil and gas E&P activities have been made in limited area such as Timan-Pechora area and Yamal peninsula in Russia, Mackenzie delta in Canada, North-Lope in Alaska and Barents Sea. Especially for offshore exploration activities in Arctic, it is highly affected by sea ice. As observed by satellite image in Arctic, no or less ice affected areas are defined such as Barents Sea and Norwegian Sea. Ice covered area in the Arctic and near of the Arctic requires serious counter measures against sea ice for putting oil and gas exploration into execution. In this lecture, recent oil and gas exploration activities in the ice covered Arctic offshore area are reviewed. In addition, history and challenge for future on new exploration license area in northeast offshore Greenland, where Greenland Petroleum Development Ltd. (GPX), Japanese Joint Venture Company established by JOGMEC, INPEX, JX, JAPEX and MOECO, are discussed. Although increase of exploration activities in Arctic is expected in the days to come, there are several technical challenges and difficulties for matter of environmental protection. It is an important mission for E&P companies to overcome those challenges and difficulties and to promote frontier oil and gas exploration in the Arctic area.
South America is one of the most promising exploration area, including exploration frontiers. As a result of recent exploration activities, remarkable discoveries were made especially in deep-water area including the presalt carbonate sections in the Santos Basin, offshore Brazil and the Upper Cretaceous turbidite sandstones offshore French Guiana.
The outstanding pre-salt discovery of the Tupi field in the Santos Basin in 2006 opened the pre-salt play and has been followed by similar giant discoveries. The main reservoir facies is known as bioclastic carbonates and microbialite developed right before evaporite deposition on the Outer High trend. The production from the pre-salt carbonates in Brazil runs up to 480,000 bbl/d as of June 2014. As the productivities varies by well, it is important to find better reservoir facies for commerciality.
Since the discovery of the Jubilee Field in June 2007 offshore Ghana, exploration has been focused on the stratigraphic play of Upper Cretaceous slope turbidites in the equatorial Atlantic Margins. In South America, the Zaedyus Field was discovered offshore French Guiana and Inpex found oil-bearing formations in Upper Cretaceous section in Block 31 offshore Suriname in 2011. It is thought that there is huge remaining exploration area for this type of play in the Atlantic Margins. Meanwhile commercial accumulations seem to be limited to only offshore Ghana at this point with remaining some challenges to find commercial size accumulations of stratigraphic traps.
Inpex has other exploration projects in the Espirito-Santo Basin, offshore Brazil and the Pelotas Basin, offshore Uruguay. We think that exploration potential of the Atlantic Margins in South America is attractive and worthy to maintain long-term E&P activities. In the meantime, it is crucial to address existing several issues including further improvement of seismic imaging, uncertainty of reservoir distribution of the pre-salt carbonates and difficulty in risk assessment of stratigraphic trap etc.
As U.S. natural gas declined below $2/mmBtu in April, 2012, with ample natural gas supplies, many Japanese got excited that they will soon be able to receive LNG from U.S. at significantly reduced costs. However, $2 natural gas could not have achieved only with abundant shale gas production but also with demand destruction in residential/commercial sectors under unseasonably warm 2011-12 winter weather. Such low natural gas prices had negative impacts on shale gas production as the price level dropped well below shale gas development/production costs, which have hampered producers' activities and instead, producers have sifted their focuses on tight oil development and production. To cover shale gas costs, U.S. natural gas prices are thought to rise to $5-5.5/mmBtu in mid 2020s. On the other hand, due to U.S. oil supply increase with steady growth of tight oil production, crude oil futures market participants expect that U.S. oil prices, which is around $100/bbl will weaken to $80s. Under such circumstances, price differentials between natural gas and crude oil will narrow, which implies that Japanese energy cost reduction with importing U.S. LNG will be limited. We should make further efforts to reduce energy costs, including ones through energy conservations. exploration, development, and liquefaction projects, carried out by Japanese companies.
Norway is one of the major oil and gas producing countries in Europe. Main production is done from the North Sea in lower latitude with the contribution from the Norwegian Sea and Barents Sea in higher latitude, and almost same undiscovered resources is expected in these areas. Petroleum potential in Norway is guaranteed by worldclass source rocks in Upper Jurassic, and therefore the nature and the habit of the petroleum system induced by these source rocks are discussed in this paper.
In the Northern North Sea, several oil families were identified by biomarker composition, especially bisnorhopane and diasteranes. Each oil family is distributed in different areas related to specific hydrocarbon kitchens. Multidimensional basin modeling revealed that the contributions from 3 source rocks (Draupne, Heather and Brent coal) differs in each kitchen, which appears to result in above nature of oil families. The different contribution is caused by the relationship of 3 source rocks to regional carrier system in each kitchen.
The established Halten and Dønna Terrace in the Norwegian Sea appear to have similar petroleum systems as the Northern North Sea. However, in the Vøring Basin, Jurassic source rocks deeply buried, and therefore the migration of oil and gas to the Cretaceous sandstones is more complex, which is the key for future exploration in the central part of the Norwegian Sea.
In the Barents Sea, the Upper Jurassic source rock matured only in the Hammerfest Basin. Detailed biomarker analysis revealed the existence of extended tricyclic hopanes in some oils suggesting the supply from the Triassic source rock. Diamondoid analysis also suggested that marine carbonate petroleum system is working in the Barents Sea, which may be originated from the Permian source rock. The distribution of these source rocks is the key for future exploration in the Barents Sea.
The endowment, resources, reserves and production capacity of oil are estimated by global oil generation, field size distribution, discovery process and decline curve analyses. The historical fluctuation of oil price is almost explained by the excess production capacity over actual consumption, which is verified by the vector autoregression analysis. These results combined with economics described by energy consumption lead to a construction of an endogenous dynamic model, which successfully replicates the historical cyclic fluctuation of production and price, and can be used to analyze the evolution of energy resources.