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North African Basin
Overcoming Hole Instability in Highly Deviated Wells in the Kafr El Sheikh Shale, Offshore Mediterranean, Egypt
Kholaif, Yasser (NOSPCO) | Elmaghraby, Mahmoud (NOSPCO) | Nago, Annick (Baker Hughes) | Embry, Jean-Michel (Baker Hughes) | Basu, Pramit (Baker Hughes) | Perumalla, Satya (Baker Hughes) | El-Said, Mohamed M. (Baker Hughes) | ElMenshawy, Ali (Baker Hughes) | Baghdadi, Ahmed (Baker Hughes)
Abstract Drilling challenges in offshore Nile Delta have been largely documented in the literature. Operators are often confronted with drilling problems related to shale swelling, cavings, tight holes in combination with increased risks of lost circulation in some of the highly depleted formations. The Kafr El Sheikh shale in particular, has been linked to many instances of wellbore instability, due to its mineralogical composition (estimated to be mostly smectite, >70%). From offset well drilling experience, it could also be noticed that insufficient mud weight was often used to drill through the Kafr El Sheikh Shale, causing wellbore failure in shear due to lack of support of the wellbore wall. In the past, multiple mud weight designs have been implemented relying solely on pore pressure as lower bound of the mud window. With the increased use of geomechanics, it has been demonstrated that the lower bound should be taken as the maximum of the pore pressure and borehole collapse pressure, thus accounting for the effects of formation pressure, horizontal and vertical stresses, rock properties as well as wellbore trajectory. It has been proven that slight overpressure is often encountered halfway through the Kafr El Sheikh formation, which would typically result in slightly higher borehole collapse pressures. In the study fields, the operator expressed interest in drilling highly deviated wells (> 60-70 degrees). This raised concerns for increased drilling challenges, especially in the Kafr El Sheikh. A comprehensive and systematic risk assessment, design of a fit-for-purpose solution and its implementation during drilling took place in the fields of interest. Offset well data analytics from the subject fields supported a holistic evaluation of drilling risks associated with the Kafr El Sheikh, providing good understanding of stress sensitivity on deviation, azimuth and lithology. Upon building a robust geomechanical model, calibrated against offset well drilling experience, pre-drill mud weight and drilling practices recommendations were provided to optimize the drilling program. Near real-time geomechanical monitoring was implemented which helped to manage the model uncertainties. The implementation of a holistic risk assessment, including geomechanical recommendations and near real-time geomechanical monitoring, was effective to lead the drilling campaign successfully. As a result, three high angle wells (> 60-70 degrees) were drilled through the challenging Kafr El Sheikh formation without any hole instability. An integrated risk assessment of hole instability, managed in stages (pre-drill and during drilling), has helped to understand and simulate the behaviors of the formation. Proactive decisions have established a controlled drilling environment for successful operations.
- Phanerozoic > Cenozoic > Neogene > Miocene (0.94)
- Phanerozoic > Cenozoic > Neogene > Pliocene (0.70)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (1.00)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Asia > Middle East > Turkey > Mediterranean Sea > Mediterranean Basin > Cilicia Basin (0.99)
- Africa > Middle East > Egypt > Nile Delta > Nile Delta Basin > Qantara Formation (0.99)
- Africa > Middle East > Egypt > Nile Delta > Nile Delta Basin > North El Amriya Concession > Kafr El Sheikh Formation (0.99)
- (5 more...)
Integrated geologic, geophysical, and petrophysical data to construct full field geologic model of Cambrian-Ordovician and Upper Cretaceous reservoir formations, Central Western Sirte Basin, Libya
Abdelnabi, Abdalla A. (Missouri University of Science and Technology) | Abushalah, Yousf (University of Texas at El Paso) | Liu, Kelly H. (Missouri University of Science and Technology) | Gao, Stephen S. (Missouri University of Science and Technology)
Abstract The Cambrian-Ordovician and Upper Cretaceous formations, which are the main oil-producing formations in the central Sirte Basin, are structurally complex. The lateral and vertical heterogeneity of the reservoir formations is not well-understood, which negatively affects the performance of the reservoirs. We constructed efficient full-field static models that incorporate the lateral and vertical variation of those reservoir formations by integrating geologic and geophysical data. We determined lithology and reservoir properties by selecting appropriate petrophysical techniques that suit the available well data and overcome issues with unreliable well-log measurements. In the process of building structural models, defining and mapping the base of the Cambrian-Ordovician Gargaf Formation was very challenging because wells did not penetrate the basal formation, and the quality of the seismic data decreases with depth. Therefore, we applied techniques of adding isochore maps of the overlying Upper Cretaceous of the Bahi and Waha Formations to map basal contact and determine the thickness of the Gargaf Formation for the first time in the area. The constructed isochore maps showed the thickness variation and the distributions of the Bahi and Waha Formations and explained the influence of Gargaf paleotopography and faults on them. The fault models combined with facies and property models suggested an interconnection among the three main reservoirs. They also indicated that the quality of the Waha reservoir enhances as the lithology varies from limestones to calcareous sandstones, whereas the quality of the Gargaf reservoir was primarily controlled by fractures. The total estimate of the original oil in place with the largest contribution of hydrocarbon volume from the Waha Formation was stock tank barrel. The created model with a fine-scale geocellular covering an area of is unique to the study area and it can be updated and refined at any time with new data production and drilling activities.
- Phanerozoic > Paleozoic (1.00)
- Phanerozoic > Mesozoic > Cretaceous > Upper Cretaceous (0.94)
- Geology > Sedimentary Geology > Depositional Environment (1.00)
- Geology > Geological Subdiscipline > Stratigraphy (0.94)
- Geology > Structural Geology > Fault (0.93)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock (0.48)
- Geophysics > Seismic Surveying > Seismic Processing (1.00)
- Geophysics > Seismic Surveying > Seismic Interpretation (1.00)
- Geophysics > Borehole Geophysics (1.00)
- (2 more...)
- North America > Canada > Saskatchewan > Western Canada Sedimentary Basin > Alberta Basin > Pikes Peak Field > Waseca Formation (0.99)
- Asia > Middle East > Kuwait > Ahmadi Governorate > Arabian Basin > Widyan Basin > Greater Burgan Field > Wara Formation (0.99)
- Asia > Middle East > Kuwait > Ahmadi Governorate > Arabian Basin > Widyan Basin > Greater Burgan Field > Ratawi Formation (0.99)
- (18 more...)
- 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)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Open hole/cased hole log analysis (1.00)
Insight on the Exploration Potential of the Ordovician Gas Play in Tunisia Ghadames Basin, North Africa
Troudi, Habib (OMV Tunesien Production GmbH) | Chevalier, Francis (OMV Tunesien Production GmbH) | Alouani, Wael (OMV Tunesien Production GmbH) | Mzoughi, Wala (OMV Tunesien Production GmbH) | Abdelkader, Omri (OMV Tunesien Production GmbH)
Abstract In Tunisian Ghadames sag basin, a significant portion of natural gas resources are looked within low permeability Ordovician sandstones deposited immediately below the Early Silurian Tannezuft world-class source rock. The objective of this study was to develop an integrated approach to better estimate the amount of gas stored in this emerging play via the analysis of four fundamental elements: 1) the thermal maturity of the Silurian โhot shalesโ source rock, 2) the trapping mechanism and the architecture of Upper Ordovician paleo-valleys, 3) the impact of diagenesis-lithofacies association on petrophysical properties, and 4) the fracture distribution/density and their contribution in the production. The Early Silurian hot shales constitute the essential ingredient for the development of a pervasive gas accumulation play. The gas generated at the deeper part of the basin has charged the underlying Ordovician low-permeability sandstones mainly through complex faults system inherited from the basement. During hydrocarbon maturation and charging, pore pressure increases at rates that exceed the normal gradients, leading to local over-pressure as seen in several wells drilled down to the Ordovician reservoirs. Lateral migration via regional faults is confirmed by numerous discoveries at the edges of the basin far away from the gas kitchen. Besides the structural closures accumulations, more complex structural/stratigraphic or purely stratigraphic traps are deemed within the Late Ordovician, and documented for instance by the development of incised paleovalleys filled with multiple fluvio-glacial and marine clastic sediments (i.e Algeria, Libya). The discovery of hydrocarbon pay zones outside of structural closures and the result of the long term tests confirm this hypothesis. Based on seismic data it is generally very hard to recognize the paleorelief marking the base of the Late Ordovician sequence. Key elements from core studies, regional correlations, isochore maps and sequence stratigraphy have been combined accordingly, leading to a conceptual model within the observed framework. It is then possible to identify the multiple incision surfaces associated with reservoirs of Jeffara and M'Krata Formations. The reservoir quality is considered as a major risk in deep areas (>4 km). Although, the primary pores space have been occluded by quartz overgrowths and clay cementation or lost by lithostatic compaction. The substantial gas rates observed in several wells drilled in the junction of NE-SW and NS fault trends constitute an evidence of the contribution of open fracture into the flow. This new insight into this play has been used by OMV to identify in Ghadames basin the area with possible "Tunnel Valley features", analogues to those drilled in Libya Murzuk basin (Ghienne, 2003).
- Africa > Middle East > Tunisia (1.00)
- Africa > Middle East > Libya (1.00)
- Africa > Middle East > Algeria (1.00)
- Phanerozoic > Paleozoic > Ordovician > Upper Ordovician (0.89)
- Phanerozoic > Paleozoic > Silurian > Llandovery (0.55)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Sandstone (1.00)
- Geology > Geological Subdiscipline > Stratigraphy (1.00)
- Geology > Sedimentary Geology > Depositional Environment > Continental Environment > Glacial Environment (0.92)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (0.58)
- Geophysics > Seismic Surveying (1.00)
- Geophysics > Borehole Geophysics (1.00)
- Africa > Middle East > Tunisia > Central Tunisia > Chotts Basin (0.99)
- Africa > Middle East > Tunisia > Berkine Basin (Trias/Ghadames Basin) > Tannezuft Formation (0.99)
- Africa > Middle East > Libya > Wadi al Hayat District > Murzuq Basin > Mamouniyat Formation (0.99)
- (8 more...)
Tectono-Stratigraphy and Reservoir Facies of Serravallian-Tortonian Succession and Its Impact on the Explorative Potential in Northeastern Offshore Nile Delta Basin, Egypt
Adel, M. (Belayim Petroleum Company) | Zaki, A. (Belayim Petroleum Company) | Nasser, M. (Belayim Petroleum Company) | Abrar, M. (Belayim Petroleum Company)
ABSTRACT The study area covers Temsah concession in the eastern Mediterranean sub-basin, Nile Delta, Egypt. Over 25 wells have been drilled within the area, targeting channelized flow deposits that covering a part of the four-way dip closure Akhen-Temsah anticline. Despite the Serravallian hydrocarbon system within this area is proved, the interpretation of the recently acquired seismic data suggests that its potentiality might be significantly larger than initially evaluated. The tectono-stratigraphic approach has been applied to delineate the Serravallian reservoir bodies in the down-flank of Akhen-Temsah anticline. The application of this approach has been proved by a gas discovery. This will open a new opportunity to explore other anomaly trends. The studied interval shows a fining upwards gamma ray log pattern with a sub-parallel thinning up-dip seismic reflectivity. Seismic interpretation was performed within Serravallian-Tortonian succession in the study area, including characterization of seismic signatures based on acoustic impedance contrast, continuity and stacking pattern. Amplitude map analysis through this interval shows SW-NE anomaly trends. New hydrocarbon potential arises under the assumption that the new identified reservoir bodies is related to the anomaly trends mapped on the over-laying levels, from those under-laying producing levels in the main field area. Reservoir rock distribution was primarily controlled by tectonics and relative sea level change, meanwhile its architecture prevents communication between permeable up-dip producing levels to down-dip younger overlying levels. Based on the mentioned assumption; the future exploration activity should be carried out over the turbiditic reservoir bodies, which located in the southeastern flank of Akhen-Temsah anticline. 1. INTRODUCTION The study area is located offshore Nile Delta, Egypt about 65 km away from Port Said city. It covers the Temsah concession (Fig. 1) with an area 1155 km2. Such area was discovered by MOBIL in 1977-1981 with the drilling of the first two wells, Temsah-1 and Temsah-2, in the southern part of the structure. The reservoir is hosted in terrigenous sandy rocks of Middle-Late Miocene (Serravallian-Tortonian) ascribed to Sidi Salim Formation. The present study addresses the tectono-stratigraphic framework of Serravallian-Tortonian succession and sheds light on the events that controlled the sedimentary processes of the studied interval in addition to distinguish the vertical and lateral facies variations of Temsah reservoirs. Also, it devotes to demonstrate the impact of tectono-stratigraphy and reservoir facies on the explorative potential in this area.
- Africa > Middle East > Egypt > Nile Delta (1.00)
- Africa > Middle East > Egypt > Port Said Governorate > Port Said (0.24)
- Phanerozoic > Cenozoic > Neogene > Miocene > Middle Miocene > Serravallian (1.00)
- Phanerozoic > Cenozoic > Neogene > Miocene > Late Miocene > Tortonian (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (1.00)
- Geology > Geological Subdiscipline > Stratigraphy (1.00)
- Geology > Structural Geology > Tectonics > Compressional Tectonics > Fold and Thrust Belt (0.78)
- Asia > Middle East > Israel > Southern District > Eastern Mediterranean Basin (0.99)
- Africa > Middle East > Egypt > Port-Said > Nile Delta Basin > Temsah Field > Wakar Formation (0.99)
- Africa > Middle East > Egypt > Port-Said > Nile Delta Basin > Temsah Field > Sidi Salem Formation (0.99)
- (6 more...)
ABSTRACT Constant bottom hole pressure (CBHP) is one of the techniques used for implementing managed pressure drilling (MPD) mode. It has been introduced to the industry since few years. It aims to provide safe drilling operations, decrease excessive mud costs by reducing lost circulation and preventing well kicks, decrease rig costs by reducing drilling problems including stuck pipe, and non-productive time (NPT). It used especially in drilling wells with a narrow mud window between pore pressure and fracture pressure gradients where selection of the mud properties and drilling techniques in such narrow windows are considered a high challenge. Its application used to reduce the effect of circulating friction loss or equivalent circulating density (ECD) by controlling the annular frictional pressure losses or using continuous circulating system. An additional circulating friction to hydrostatic head can result in formation fracture in drilling or circulation operations, also when stopping circulation the hydrostatic pressure could lies below the formation pore pressure. CBHP could be achieved using the following techniques:Application of Backpressure (ABP), and Continuous Circulation. This paper is devoted to show the tools used to achieve continuous circulation and the candidates of implementing such technique. The paper provides a case study that illustrates how continues circulation used to enhance the casing design and the mud program. It also illustrates the economic benefits using a cost analysis of the phases that used ENI's circulating device (E-CDโข system) by comparing between conventional drilling techniques and Constant bottom hole pressure-continuous circulation-applications in wells drilled in TEMSAH Field. INTRODUCTION Continuous circulation is considered one of the methods used to achieve Continuous bottom hole pressure CBHP through controlling the effect of circulating friction loss or equivalent circulating density (ECD). Continuous circulation could be applied using E-CDโข system (ENI's circulating device), Continuous circulating valve (CCV) and Continuous Circulation System (CCS).
- North America > United States (1.00)
- Africa > Middle East > Egypt > Mediterranean Sea (0.72)
- Africa > Middle East > Egypt > Port-Said (0.61)
- Geology > Geological Subdiscipline > Geomechanics (0.76)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (0.32)
- Africa > Middle East > Egypt > Port-Said > Nile Delta Basin > Temsah Field > Wakar Formation (0.99)
- Africa > Middle East > Egypt > Port-Said > Nile Delta Basin > Temsah Field > Sidi Salem Formation (0.99)
- Africa > Middle East > Egypt > Mediterranean Sea > North African Basin > Wakar Formation (0.99)
- (3 more...)
Tight Oil Field Development Optimization Based on Experience of Canadian Analogs
Karpov, V. B. (RITEK) | Parshin, N. V. (RITEK) | Sleptsov, D. I. (RITEK) | Moiseenko, A. A. (RITEK) | Ryazanov, A. A. (RITEK) | Golovatskiy, Y. A. (RITEK) | Petrashov, O. V. (RITEK) | Zhirov, A. V. (RITEK) | Kurelenkova, Y. V. (RITEK) | Ishimov, I. A. (RITEK) | Im, P. T. (Baker Hughes)
Abstract The paper presents a study of field development optimization of the large tight oil field in West Siberia. The field is at an early development stage and is characterized by low permeability (less than 1 mD). It is developed by horizontal wells with multistage hydraulic fracturing. Analysis of available information about the field revealed the potential to improve field development efficiency. Field development analysis and optimization were carried out based on the experience of development of similar Canadian reservoirs. Two large fields were selected as analogues: Bakken ViewField and Pembina Cardium. The data on these fields is publicly available. These fields are developed during a long period of time enabling operating companies to learn from experience and use new knowledge and data to optimize completions systems and development strategies as a whole. Therefore it is possible to not only analyze the current field development stage, but also trace the evolution of approaches and assess, what benefits can be obtained from making various changes to the applied technologies and field development strategy. The positive experience of development of the Canadian fields formed the basis for the field development optimization options. A set of suggested project decisions will enable improvement in field development efficiency and, in case of confirming by pilot projects, can be recommended for full-field implementation in the considered field and in the analogue fields.
- Europe (0.94)
- Asia (0.94)
- North America > Canada > Alberta (0.47)
- North America > United States > Mississippi > Marion County (0.24)
- Geology > Geological Subdiscipline > Geomechanics (0.68)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (0.47)
- North America > Canada > Alberta > Western Canada Sedimentary Basin > Alberta Basin > Deep Basin > Cardium Field > Cardium Formation (0.99)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > North Kuwait Jurassic (NKJ) Fields > Marrat Formation > Upper Marrat Formation (0.98)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > North Kuwait Jurassic (NKJ) Fields > Marrat Formation > Sargelu Formation (0.98)
- (12 more...)
Abstract In the Murzuq Basin, the Late Ordovician glaciogenic succession forms a very complex clastic reservoir system. Although the structural setting is simple, the architecture of the stratigraphic succession is particularly intricate, and conventional wireline logs display rather homogeneous signatures. However, when exposed, the glaciogenic sedimentary succession indicates a very large range of depositional environments and clear stratigraphic changes. Based on high-quality processing and interpretation of wireline microresistivity image logs over a single well, our method allows the precise recognition of the internal sedimentary structures and supports the interpretation of the depositional environments within the Late Ordovician succession. During interpretation, it is possible to draw a descriptive sedimentological log, similar to a standard log from cores or outcrops. The image log is interpreted like a regular sedimentary log and compared to an outcrop analog from the nearby outcrop area of Ghat. The success of the well analysis resides in the quality of the borehole image log, permitting the recognition of sandstone grain sizes, textures (facies), and sorting. In addition, crucial information is extracted from the identification of glacial surface and ice-flow orientations, which, combined with the recognition of major transgressive events, allows the recognition and correlation of glacial-type stratigraphy. As in the modern Pleistocene glaciation, stadial/interstadial and glacial/interglacial stages are identified from resistivity imaging of the Libyan Ordovician succession. In addition to the unprecedented potential of correlation between wells within the basin, the sedimentary information extracted from the borehole image log provides important insights on the paleogeographic context of the basin and thus on the exploration potential of the prolific Ordovician-Silurian petroleum system.
- Geophysics > Seismic Surveying > Borehole Seismic Surveying (1.00)
- Geophysics > Borehole Geophysics (1.00)
- Africa > Middle East > Libya > Murzuq District > Murzuq Basin (0.99)
- Africa > Middle East > Libya > Djado Basin (0.99)
- Africa > Middle East > Libya > Mediterranean Sea > North African Basin (0.98)
- (5 more...)
- Reservoir Description and Dynamics > Reservoir Characterization (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Open hole/cased hole log analysis (1.00)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring > Borehole imaging and wellbore seismic (1.00)
Abstract The study area covers Temsah concession in the eastern sub-basin, offshore Nile Delta, Egypt. Despite the Serravallian play within this area is proven, observations made on recently acquired seismic data suggest its potentiality might be significantly larger than initially evaluated. Over 25 wells have been drilled within Temsah Development Lease since late 70's targeting turbiditic channelized flow deposits fitting a part of the four way dip closure Akhen-Temsah anticline. The interval of study shows a general fining upwards GR log pattern with a sub-parallel thinning up-dip seismic reflectivity. Amplitude map analysis through this interval shows southwest-northeast anomaly trends, shifting upwards to the southeast and becoming thinner and narrower. New hydrocarbon potential arises under the assumption that reservoir rock distribution is restricted to the anomaly trends mapped on the over-laying levels, from those producing from the main field area, and located down-dip on the southeastern flank of the structure. The associated risk derives from the reservoir architecture and possible lateral up-dip communication to underlying beds through permeable beds.
- Phanerozoic > Cenozoic > Paleogene (1.00)
- Phanerozoic > Cenozoic > Neogene > Miocene > Middle Miocene > Serravallian (0.65)
- Geology > Sedimentary Geology > Depositional Environment > Marine Environment (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (1.00)
- Geology > Geological Subdiscipline > Stratigraphy (1.00)
- Geology > Structural Geology > Tectonics > Compressional Tectonics > Fold and Thrust Belt (0.36)
- Asia > Middle East > Israel > Southern District > Eastern Mediterranean Basin (0.99)
- Africa > Middle East > Egypt > Nile Delta > Nile Delta Basin > Qantara Formation (0.99)
- Africa > Middle East > Egypt > Kafr El Sheikh Governorate > Nile Delta Basin > South Disouq Concession > Madi Formation (0.99)
- (6 more...)
Abstract Graptolite shales are a type of fossil shales that contain a large number of graptolite imprints and remains. These deposits are characterized by high TOC contents (Corg = 2โ18%). Based on the data of many studies, graptolite shales are one of the main hydrocarbon sources that formed oil and gas fields in Paleozoic deposits around the world, e.g., the Silurian graptolite shales make up to 9โ15% of all hydrocarbons that form the oil and gas fields in the largest petroleum basins. The main accumulation areas of graptolite shales during the Ordovician were the margins of Baltica, Laurentian, and Gondwana (Yapetus Ocean shelf). One of the belts (northern) extended from the southern periphery of the Baltic Shield to the Appalachian Basin; another (southern) belt stretched from the sedimentary basins of the AfricanโArabian margin of Gondwana to the shelf and continental slope of southern Laurentia, the present-day Western Interior Coal Region, Permian basin, and Ouachita belt. In the Silurian, the southern (northern Gondwanan) belt began to play the leading role, while another northern belt incorporated the southern regions of Baltica and the microcontinents approaching to it (Armorica, Perunica, and Iberica). In the sedimentary basins of Laurentia, Silurian graptolite shales were not widespread; they are reported only for east Greenland and in the Michigan basin. The contribution of Paleozoic graptolite shales into the generation of hydrocarbons that formed multiple oil and gas fields worldwide is quite high. Based on the data of G. Ulmishek and H. Klemme (1991), oil-and-gas source rocks of Ordovician and Silurian ages, which are mostly graptolite shales, produced up to 9% of all the hydrocarbon reserves discovered by the late 20th century. For particular regions, this contribution was even more. It is believed that Silurian graptolite shales produced 80 to 90% of the hydrocarbons stored in giant oil field of North Africa. The Silurian graptolite shales are also thought to have played the main role in the formation of the South Pars/North Field gas condensate field in the Persian Gulf, which is the largest field for natural gas in the world. During work with more than 41 publications schemes of distribution of graptolitic shales in Ordovician and Silurian was composed. Such knowledge about source rock is one of the many steps to Petroliferous basins insight.
- North America > United States (1.00)
- Africa > Middle East > Algeria (0.94)
- Asia > Middle East > Qatar > Arabian Gulf (0.54)
- Asia > Middle East > Iran > Arabian Gulf (0.54)
- Phanerozoic > Paleozoic > Ordovician (1.00)
- Phanerozoic > Paleozoic > Silurian > Llandovery (0.69)
- North America > United States > West Virginia > Appalachian Basin (0.99)
- North America > United States > Virginia > Appalachian Basin (0.99)
- North America > United States > Texas > Permian Basin > Yeso Formation (0.99)
- (56 more...)
Abstract The unprecedented success of North American shale gas has lead to a proliferation of international shale gas exploration plays, particularly in Europe. Whilst differing basin geometries and structural geology provide significant local constraints on development strategies, global sea level changes provide a framework by which different stratigraphic intervals can be evaluated at a "continental" level. Using the Hallam Curve we have identified a number of global sea level maxima which correspond to significant periods of prospective gas shale deposition. These typically correspond to periods of relatively high sea level, frequently post-glacial, during which continental shelves were inundated and clastic sediment supply was limited because of the high base level. Under-filled marginal sedimentary basins appear particularly attractive exploration targets. Shales deposited under these conditions typically have geochemical and petrophysical characteristics comparable to North American shales which are currently in production. Several orogenic events severely influence European shales in terms of organic maturity, hydrocarbon generation and fracture generation, key prospective horizons(in ascending stratigraphical sequence) include the Middle Cambrian Alum Shale, Lower Silurian (Llandovery), the Devonian (Fammenian/Frasnian), Lower Carboniferous (Serpukhovian), Lower Jurassic (Toarcian), the Upper Jurassic (Kimmeridge Clay) and the Tertiary Eocene and Oligocene shales common to central Europe. This paper will outline the authors initial exploration strategy focusing on three main intervals: Lower Palaeozoic of Central Europe, the Namurian of NW England and the Jurassic Posidonia Formation of the Roer Valley Graben in Holland.
- Phanerozoic > Paleozoic > Devonian (1.00)
- Phanerozoic > Mesozoic > Jurassic > Middle Jurassic (0.71)
- Phanerozoic > Paleozoic > Carboniferous > Mississippian > Upper Mississippian > Serpukhovian (0.47)
- Phanerozoic > Mesozoic > Jurassic > Lower Jurassic > Toarcian (0.35)
- North America > United States > Texas > Permian Basin > Yeso Formation (0.99)
- North America > United States > Texas > Permian Basin > Yates Formation (0.99)
- North America > United States > Texas > Permian Basin > Wolfcamp Formation (0.99)
- (40 more...)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Shale oil (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Shale gas (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Exploration, development, structural geology (1.00)