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Journal articles on the topic "Low overburden"

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Ji, Yanju, Shangyu Du, Lijun Xie, Kai Chang, Yang Liu, Yi Zhang, Xiaoming Xie, Yuan Wang, Jun Lin, and Liangliang Rong. "TEM measurement in a low resistivity overburden performed by using low temperature SQUID." Journal of Applied Geophysics 135 (December 2016): 243–48. http://dx.doi.org/10.1016/j.jappgeo.2016.09.027.

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Lo, S. C. R. "Pull-Out Resistance of Polyester Straps at Low Overburden Stress." Geosynthetics International 5, no. 4 (January 1998): 361–82. http://dx.doi.org/10.1680/gein.5.0126.

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Su, Xiaochao, Zhilong Chen, Xudong Zhao, Xiaobin Yang, Qilin Feng, and Haizhou Tang. "Optimization Design of Underground Space Overburden Thickness in a Residential Area Concerning Outdoor Thermal Environment Evaluation." Sustainability 10, no. 9 (September 7, 2018): 3205. http://dx.doi.org/10.3390/su10093205.

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Reasonable design of the overburden thickness of underground space (OTUS) can influence the outdoor thermal environment by affecting the ground plant communities. To optimize the design of the OTUS for improving the outdoor thermal environment, this study summarized the influence mechanism of the OTUS on the outdoor thermal environment and proposed a framework of the optimization design of underground space overburden thickness. A typical row layout residential area in Nanjing, China, was taken as the research object on which to perform a numerical study of the influence of plant communities formed by two types of plant collocations (a middle- and low-level plant collocation and a middle- and high-level plant collocation) on the outdoor thermal environment (airflow field, air temperature, relative humidity and thermal comfort) under three different ratios of trees to shrubs (2:3, 1:2, and 1:3), and to provide suggestions regarding the design of the OTUS according to the designer’s requirements. The conclusions were summarized as follows: (1) If a designer wants to enhance outdoor ventilation, the OTUS should be designed to satisfy the requirements for the middle- and low-level plant collocations and the overburden thickness of the 2/5 underground space development area should be set to 80~100 cm, the overburden thickness of the other 2/5 area should be set to 45~60 cm and the overburden thickness of the remaining 1/5 area should be set to 30~45 cm. (2) If a designer wants to reduce air temperature, increase relative humidity, and improve outdoor thermal comfort, the OTUS should be designed to satisfy the requirements for middle- and high-level plant collocations and the overburden thickness of the 1/4 underground space development area should be set to 80~100 cm, and the overburden thickness of the remaining 3/4 area should be set to 45~60 cm.
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Gastrich, Holger, Claus Gößling, Reiner Klingenberg, Kevin Kröninger, Till Neddermann, Christian Nitsch, Thomas Quante, and Kai Zuber. "The Dortmund Low Background Facility — Low-background gamma ray spectrometry with an artificial overburden." Applied Radiation and Isotopes 112 (June 2016): 165–76. http://dx.doi.org/10.1016/j.apradiso.2016.03.025.

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Kapure, G. U., C. B. Rao, V. D. Tathavadkar, and R. Sen. "Direct reduction of low grade chromite overburden for recovery of metals." Ironmaking & Steelmaking 38, no. 8 (November 2011): 590–96. http://dx.doi.org/10.1179/1743281211y.0000000028.

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Das, Sarat Kumar, Mahasakti Mahamaya, and Krishna R. Reddy. "Coal mine overburden soft shale as a controlled low strength material." International Journal of Mining, Reclamation and Environment 34, no. 10 (February 11, 2020): 725–47. http://dx.doi.org/10.1080/17480930.2020.1721043.

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Negrão, Leonardo Boiadeiro Ayres, Herbert Pöllmann, and Marcondes Lima da Costa. "Production of low-CO2 cements using abundant bauxite overburden “Belterra Clay”." Sustainable Materials and Technologies 29 (September 2021): e00299. http://dx.doi.org/10.1016/j.susmat.2021.e00299.

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Pettifer, G. R., N. Djordjevic, D. Heislers, J. Schaeffer, and J. A. Withers. "Geophysical and image processing methods for detection of fireholes in brown coal, Latrobe Valley." Exploration Geophysics 20, no. 2 (1989): 153. http://dx.doi.org/10.1071/eg989153.

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Fireholes at the top of the thick Latrobe Valley brown coal seams pose a geotechnical hazard to overburden dredges and reduce coal reserves. Overburden thickness (typically 10 to 15 m) is up to 50 m in the fireholes, which are from 20 to hundreds of metres in diameter and are infilled with baked clays, soft lacustrine clays and alluvial deposits.Given the complexity of firehole geometry and overburden geology, firehole definition prior to overburden stripping, by drilling alone, is expensive and is not definitive. To improve firehole exploration, geophysical methods were tried in a test area with good borehole control (115 holes), near Morwell open cut.Grid geophysics (20m. � 20m., 2805 grid stations) using gravity, EM34 20 m loop conductivity and high resolution magnetics gave very good results. Shallow seismic reflection methods were not successful.Residual gravity defined overburden thickness variations best with gravity highs of up to 6.5 micrometres/sec2 over the fireholes. EM conductivity showed reasonable correlation with overburden thickness, with EM conductivity highs over fireholes infilled with lower resistivity lacustrine clays and silts. High resolution magnetics using a TM-3 caesium vapour magnetometer, despite high cultural interference, showed broad, low amplitude highs over fireholes where higher susceptibility baked clays are thickest. The three geophysical data sets and overburden data were gridded (5m. � 5m.) and the grids dumped to a MicroBrian image processing system. Conventional image processing analysis was carried out to compare, enhance, filter, display and classify the complementary data sets. A classification scheme for overburden type based on geophysical responses plus a routine firehole exploration methodology using residual gravity, EM, magnetics, progressive drilling data and the image processor was devised to reduce drilling costs and increase exploration confidence. The case history presents the results of the grid geophysics and image processing approach.
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El-Aswad, Ali, Intesar Elagil, and Salem Fatooh. "STRESS EFFECT ON CEMENTATION FACTOR OF SANDSTONE ROCKS TYPE EVIDENCE FOR A VARIABLE ARCHIE POROSITY EXPONENT “m”." Scientific Journal of Applied Sciences of Sabratha University 1, no. 1 (December 27, 2018): 50–66. http://dx.doi.org/10.47891/sabujas.v1i1.50-66.

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Ancient sandstones include important reservoirs for hydrocarbons (oil and gas). This research provides an experimental investigation on the influence of variations in confining pressure on cementation factor of two wells located in Sirt basin. Measurements of formation resistivity factor versus cementation factor for sandstone samples which were collected from both wells at different confining pressures were carried out. The Effects of confining stress on the electrical properties of the rock samples were studied and analyzed. The results showed that the confining pressure variations depend on the pore structure of the studied rock. Furthermore, it can be concluded that the electrical resistivity of rocks is function of pore size distribution and how the fluids were distributed in the pore spaces. The effect of overburden pressure and the porosity variation on cementation factor is also investigated for different rock types. It has been concluded that the compaction due to overburden pressure generally causes a considerable increase in resistivity, especially in poorly cemented rocks. In low-porosity rocks, resistivity measurements determined under representative overburden pressures that are strongly recommended to improve well log interpretation.
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Dreesen, David R., John T. Harrington, Anne M. Wagner, Leigh Murray, and Peixin Sun. "TESTING NATIVE GRASSES FOR SURVIVAL AND GROWTH IN LOW pH MINE OVERBURDEN." Journal American Society of Mining and Reclamation 2001, no. 1 (2001): 2–17. http://dx.doi.org/10.21000/jasmr01010002.

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Dissertations / Theses on the topic "Low overburden"

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Karimi, Seyedhamid. "Integrated characterisation of mud-rich overburden sediment sequences using limited log and seismic data : application to seal risk." Thesis, Durham University, 2015. http://etheses.dur.ac.uk/11285/.

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Muds and mudstones are the most abundant sediments in sedimentary basins and can control fluid migration and pressure. In petroleum systems, they can also act as source, reservoir or seal rocks. More recently, the sealing properties of mudstones have been used for nuclear waste storage and geological CO2 sequestration. Despite the growing importance of mudstones, their geological modelling is poorly understood and clear quantitative studies are needed to address 3D lithology and flow properties distribution within these sediments. The key issues in this respect are the high degree of heterogeneity in mudstones and the alteration of lithology and flow properties with time and depth. In addition, there are often very limited field data (log and seismic), with lower quality within these sediments, which makes the common geostatistical modelling practices ineffective. In this study we assess/capture quantitatively the flow-important characteristics of heterogeneous mud-rich sequences based on limited conventional log and post-stack seismic data in a deep offshore West African case study. Additionally, we develop a practical technique of log-seismic integration at the cross-well scale to translate 3D seismic attributes into lithology probabilities. The final products are probabilistic multiattribute transforms at different resolutions which allow prediction of lithologies away from wells while keeping the important sub-seismic stratigraphic and structural flow features. As a key result, we introduced a seismically-driven risk attribute (so-called Seal Risk Factor "SRF") which showed robust correspondence to the lithologies within the seismic volume. High seismic SRFs were often a good approximation for volumes containing a higher percentage of coarser-grained and distorted sediments, and vice versa. We believe that this is the first attempt at quantitative, integrated characterisation of mud-rich overburden sediment sequences using log and seismic data. Its application on modern seismic surveys can save days of processing/mapping time and can reduce exploration risk by basing decisions on seal texture and lithology probabilities.
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Chen, Chien-Han, and 陳建翰. "Two dimensional simulation on shear-induced dilatant behavior at nail-soil interface under low overburden pressure." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/86603086016536909223.

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碩士
淡江大學
土木工程學系碩士班
101
Soil nailing is an in-situ reinforcement technique in recent years, to retain excavations and stabilize slopes. The nails are installed at predetermined locations using a drilling and grouting method appropriate for the soil to retain excavations and stabilize slopes. Nails may be driven as well. The frictional characteristic of the interface between the nail and soil is the most important reinforcing mechanism for nailed retaining structures. The interfacial shear resistance depends on the effect range of neighbor particles subject to the nail pullout. During the pullout of a nail, the nail tends to drag the surrounding soil particles to move together. The friction on the soil-nail interface would cause adjacent particles to move through the friction between their contacts. This propagates further away from the soil nail resulting in shear band formation and development. In this study, the microscope movement of soil particles around a soil nail is observed through a two-dimensional soil nail pullout test in a model sandbox. The test parameters included variations in the screw pitch of nail (Sp), the particle diameter (d), and the relative density of particle (Dr). The surface screw pitches of the nails were 1 mm, 2.05 mm, and 4.10 mm, respectively. A smooth surface was used to represent a nail with zero roughness. The diameters of sand particles were 0.84 mm and 1.90 mm, respectively. The experimental results showed that the thickness of shear band depends on the geometric relationship between the surface roughness and the particle size of sand. The shear band thickness and the peak apparent friction coefficient were the maximum when the ratio of the screw pitch to particle diameter (Sp/d) or the diameter protrusion ratio (E) were approached one.
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Kistenmacher, Ann. "Food addiction : a cost-effective treatment proposal within a developing country context." Diss., 2018. http://hdl.handle.net/10500/24503.

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This study explores the possible efficacy of a low carbohydrate and high fat nutritional intervention (LCHF) as a treatment possibility aiming to improve the ability of self-control and regulation in the context of carbohydrate-addiction. The study first outlines why increased simple carbohydrate consumption has been implicated as a risk-factor in numerous chronic conditions, and then explores the possibility that a reduction of such consumption could lower general medical expenditure in the healthcare sector of already overburdened institutions, especially in developing countries like South Africa. Since the neurobiological evidence for food addiction is compelling, this study investigates the impact of a low carbohydrate and high fat eating (LCHF) regimen by measuring the change in the severity of addictive behaviour in relation to a reduced carbohydrate consumption. Results indicate that a LCHF nutritional intervention lessened addictive behaviour after just 30 days, resulting in a statistically significant decrease in addiction symptoms from day 1 to day 30. The weight and BMI values of the participants recorded at the end of the study showed a reduction from those obtained during the pre- treatment stage, and the self-perceived ‘feeling in control’ also improved in all participants after the intervention. The introduction of a LCHF nutritional intervention presents a relatively cost-effective treatment and preventative measure to combat carbohydrate over-consumption and its numerous health complications, and it is therefore hoped that the positive findings of this study will foster further research, using larger samples, into this type of nutritional intervention against addictive eating behaviour.
Psychology
M.A. (Psychology)
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Books on the topic "Low overburden"

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Madsen, Mikael Rask. The European Court of Human Rights. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198795582.003.0011.

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This chapter studies the transformation of the authority of the European Court of Human Rights (ECtHR) since its genesis. It shows how the ECtHR, until the mid-to-late 1970s, struggled to maintain narrow legal authority. Both the Court’s caseload and civil society engagement changed fundamentally however throughout the late 1980s and the 1990s when the ECtHR gained intermediate and extensive authority in large parts of Europe. During this period, the Court became the de facto Supreme Court of human rights in Europe. Starting around 2000, the Court became increasingly overburdened. It was in the context that a number of member states launched a systematic critique of both the Court’s power over national law and politics and the quality of the Court’s judges and their judgments. This discontent climaxed with the 2012 Brighton Declaration, adopted by all forty-seven member states, which began an institutionalized process that aimed to limit the ECtHR’s power.
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Book chapters on the topic "Low overburden"

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Krieger, Heike. "Sentenza 238/2014: A Good Case for Law-Reform?" In Remedies against Immunity?, 71–89. Berlin, Heidelberg: Springer Berlin Heidelberg, 2021. http://dx.doi.org/10.1007/978-3-662-62304-6_4.

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AbstractSentenza 238/2014 is an important judgment which does not only concern the concrete case at hand but also pushes for a change in the law of state immunity. However, such attempts at law-making by national courts may not always attain their goal but may exert adverse effects which are harmful for the international legal order. Sentenza 238/2014 may have an impact on three different yet related issues central to the future development of international law: the relationship between international and national law, exceptions to immunities, and individual reparations in cases of mass atrocities.This chapter criticises law-making through non-compliance with international judicial decisions by national courts. Judges in democratic states under the rule of law who try to push for law-reform, by initiating non-compliance with decisions of international courts, should be aware that they may act in the company, and thereby in support of, courts in regimes with autocratic tendencies, such as the Russian Constitutional Court, which refuses to comply with judgments of the European Court of Human Rights. Furthermore, the chapter argues that immunity from jurisdiction and immunity from execution should be kept distinct and that human rights exceptions should not be applied to immunity from execution. Such a differentiation remains justified because measures of constraint against property used for government non-commercial purposes intrude even further onto sovereign rights than the institution of proceedings before courts in the forum state. It is particularly difficult for states to protect assets and other property situated in a foreign state. These assets may therefore be more susceptible to abusive enforcement measures while simultaneously forming an essential basis for the actual conduct of international relations.The chapter concludes by advocating a cautious approach to individual reparations in cases of mass atrocities. This more cautious approach observes the complexities of ending armed conflicts and negotiating peace deals. An individual right to monetary compensation based on civil claims processes does not allow for taking into account broader political considerations related to establishing a stable post-war order. Such a right is conducive to bilateral settlements between the state parties concerned, which might create new injustices towards other groups of victims. It might also overburden negotiations for a settlement to an ongoing armed conflict.The chapter thereby starts from the assumption that the stability of the international legal order itself as guaranteed by concepts such as immunities or the respect for its judicial organs serves to protect human rights, albeit indirectly.
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Zingano, A., E. Palma Filho, J. Costa, and J. Koppe. "Displacements estimate due twin tunnel excavation under low overburden." In Underground Space – The 4th Dimension of Metropolises. Taylor & Francis, 2007. http://dx.doi.org/10.1201/noe0415408073.ch106.

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"Displacements estimate due twin tunnel excavation under low overburden." In Underground Space - The 4th Dimension of Metropolises, Three Volume Set +CD-ROM, 663–66. CRC Press, 2007. http://dx.doi.org/10.1201/noe0415408073-84.

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Neun, E., and S. Sabew. "Compensation grouting for conventional tunnelling with low overburden at the Oberau Bypass Tunnel." In Geotechnical Aspects of Underground Construction in Soft Ground, 804–11. CRC Press, 2021. http://dx.doi.org/10.1201/9780429321559-106.

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H. Altiti, Awwad, Rami O. Alrawashdeh, and Hani M. Alnawafleh. "Open Pit Mining." In Mining Techniques - Past, Present and Future. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.92208.

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Open pit mining method is one of the surface mining methods that has a traditional cone-shaped excavation and is usually employed to exploit a near-surface, nonselective and low-grade zones deposits. It often results in high productivity and requires large capital investments, low operating costs, and good safety conditions. The main topics that will be discussed in this chapter will include an introduction into the general features of open pit mining, ore body characteristics and configurations, stripping ratios and stripping overburden methods, mine elements and parameters, open pit operation cycle, pit slope angle, stability of mine slopes, types of highwall failures, mine closure and reclamation, and different variants of surface mining methods including opencast mining, mountainous mining, and artisan mining.
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Grossauer, K., E. Carrera, W. Schmid, and T. Zieger. "Tunnel design and construction in swelling ground with low overburden and hydrothermal ground water conditions." In Tunnels and Underground Cities: Engineering and Innovation meet Archaeology, Architecture and Art, 5659–67. CRC Press, 2019. http://dx.doi.org/10.1201/9780429424441-598.

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Grossauer, K., E. Carrera, W. Schmid, and T. Zieger. "Tunnel design and construction in swelling ground with low overburden and hydrothermal ground water conditions." In Tunnels and Underground Cities: Engineering and Innovation meet Archaeology, Architecture and Art, 5659–67. CRC Press, 2020. http://dx.doi.org/10.4324/9781003031857-45.

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Grossauer, K., E. Carrera, W. Schmid, and T. Zieger. "Tunnel design and construction in swelling ground with low overburden and hydrothermal ground water conditions." In Tunnels and Underground Cities: Engineering and Innovation meet Archaeology, Architecture and Art, 5659–67. CRC Press, 2020. http://dx.doi.org/10.1201/9781003031857-45.

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Moritz, B., R. Matt, and R. Heissenberger. "Geotechnical and monitoring challenges during excavation of a large urban tunnel in soft ground and low overburden." In Harmonising Rock Engineering and the Environment, 1057–63. CRC Press, 2011. http://dx.doi.org/10.1201/b11646-196.

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Hearne, Rory. "Generation Rent." In Housing Shock, 21–44. Policy Press, 2020. http://dx.doi.org/10.1332/policypress/9781447353898.003.0002.

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This chapter details how the younger generations and lower-income households are most affected by the housing and homelessness crisis. It shows how huge aspects of their lives have become precarious and insecure, as a result of insecure, low-paid and often part-time jobs, and insecure and unaffordable housing. Generation Rent is the new housing precariat, living with precarious housing, precarious work contracts and an inability to access mortgage credit, alongside unaffordable house prices and rent. It details the structural shift in Ireland’s housing system: decline in home-ownership rates and rise in private rental sector. Generation Rent now extends to the middle-aged and older generations as shown in the increase in the number of people renting in their 40s and 50s. It looks at increasing housing cost overburden rates where young people on low incomes are most severely affected by the issue of housing affordability than young people on higher incomes. Generation Rent also includes Generation Stuck at Home - those forced to live at home with theirparents as they cannot afford to move out into the rental sector, orbecause they have been evicted, unable to meet mortgages, cannot access social housing, or are trying to savefor a deposit.
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Conference papers on the topic "Low overburden"

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Chabronova, Jana. "IMPACT THE TUNNEL EXCAVATION WITH LOW OVERBURDEN TO ROCK MASS." In 19th SGEM International Multidisciplinary Scientific GeoConference EXPO Proceedings. STEF92 Technology, 2019. http://dx.doi.org/10.5593/sgem2019/1.2/s02.042.

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Dzulkefli, Farah Syazana, Kefeng Xin, Ahmad Riza Ghazali, Guo Qiang, and Tariq Alkhalifah. "Full Wavefield Redatuming: Accurate Velocity Modelling for Imaging Beneath Complex Overburden." In International Petroleum Technology Conference. IPTC, 2021. http://dx.doi.org/10.2523/iptc-21771-ms.

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Abstract Salt is known for having a generally low density and higher velocity compared with the surrounding rock layers which causes the energy to scatter once the seismic wavefield hits the salt body and relatively less energy is transmitted through the salt to the deeper subsurface. As a result, most of imaging approaches are unable to image the base of the salt and the reservoir below the salt. Even the velocity model building such as FWI often fails to illuminate the deeper parts of salt area. In this paper, we show that Full Wavefield Redatuming (FWR) is used to retrieved and enhance the seismic data below the salt area, leading to a better seismic image quality and allowing us to focus on updating the velocity in target area below the salt. However, this redatuming approach requires a good overburden velocity model to retrieved good redatumed data. Thus, by using synthetic SEAM model, our objective is to study on the accuracy of the overburden velocity model required for imaging beneath complex overburden. The results show that the kinematic components of wave propagation are preserved through redatuming even with heavily smoothed overburden velocity model.
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Zargar, Zeinab, and S. M. Farouq Ali. "How to Space SAGD Well Pairs for Optimal Performance." In SPE Annual Technical Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/206381-ms.

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Abstract Steam-Assisted Gravity Drainage (SAGD) is a remarkably successful process for the tar sands (oil sands). Two closely spaced parallel horizontal wells, injector above the producer, form a SAGD well pair. Steam is injected to provide heat to the reservoir oil and mobilize it. The low viscosity oil drains down to the producer under the gravity effect. Parallel well pairs 1000 m long are utilized in the process, spaced 100 m apart horizontally almost in all projects. In this work, an analytical model for the SAGD process is introduced by coupling heat and fluid flow and constitutive equations. A moving boundary, counter-current flow approach is used for the steam chamber rise and subsequent sideways expansion. The model is unique because it assumes the steam injection rate is constant and it permits modeling of the late phase of SAGD when adjacent well pair interference occurs. This leads to a reduction in heat loss to the overburden and a decline in oil production rate. This study examines the question of optimal well pair spacing in relation to the formation thickness and in-place oil. The effect of other variables on SAGD performance is investigated. A case study was performed using Christina Lake oil sand properties to show how the project performance varies under different senerios involving well pair spacing, reservoir thickness, steam injection rate, and steam quality. Results show that, in evaluating a SAGD pad performance, as the spacing is increased, the cumulative oil production decreases, with a simultanous increase in the cumulative steam-oil ratio at the same steam injection rate. However, a smaller portion of injected heat is lost to the overburden. It is concluded that a smaller well spacing requires more wells to deplete the whole pad area. On the other hand, a larger pattern well spacing affects oil recovery and heat consumption. Different conclusions are derived for the same pattern well spacing value using a single well pair model and pattern well pair configuration. Results also show that SAGD well pair spacing can be increased with an increase in formation thickness. The computational procedure is simple and makes it possible to examine a series of options for well spacing for a given set of conditions. This study presents for the first time an analytical relation between SAGD pattern well pair spacing and oil recovery.
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Prasetyo, A. ,. C. "Depositional Environment Drive as Overpressure Generation: Study Case in “Gap” Field, North West Java Basin." In Digital Technical Conference. Indonesian Petroleum Association, 2020. http://dx.doi.org/10.29118/ipa20-sg-276.

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Overpressure existence represents a geological hazard; therefore, an accurate pore pressure prediction is critical for well planning and drilling procedures, etc. Overpressure is a geological phenomenon usually generated by two mechanisms, loading (disequilibrium compaction) and unloading mechanisms (diagenesis and hydrocarbon generation) and they are all geological processes. This research was conducted based on analytical and descriptive methods integrated with well data including wireline log, laboratory test and well test data. This research was conducted based on quantitative estimate of pore pressures using the Eaton Method. The stages are determining shale intervals with GR logs, calculating vertical stress/overburden stress values, determining normal compaction trends, making cross plots of sonic logs against density logs, calculating geothermal gradients, analyzing hydrocarbon maturity, and calculating sedimentation rates with burial history. The research conducted an analysis method on the distribution of clay mineral composition to determine depositional environment and its relationship to overpressure. The wells include GAP-01, GAP-02, GAP-03, and GAP-04 which has an overpressure zone range at depth 8501-10988 ft. The pressure value within the 4 wells has a range between 4358-7451 Psi. Overpressure mechanism in the GAP field is caused by non-loading mechanism (clay mineral diagenesis and hydrocarbon maturation). Overpressure distribution is controlled by its stratigraphy. Therefore, it is possible overpressure is spread quite broadly, especially in the low morphology of the “GAP” Field. This relates to the delta depositional environment with thick shale. Based on clay minerals distribution, the northern part (GAP 02 & 03) has more clay mineral content compared to the south and this can be interpreted increasingly towards sea (low energy regime) and facies turned into pro-delta. Overpressure might be found shallower in the north than the south due to higher clay mineral content present to the north.
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Havlova´, Va´clava, Radek Cˇervinka, Ulrich Noseck, Thomas Brasser, and Josef Havel. "The Ruprechtov Natural Analogue Site (CZ) Study: Mobile Natural Organic Matter Identification, Characterisation and Link to PA Relevant Processes." In ASME 2009 12th International Conference on Environmental Remediation and Radioactive Waste Management. ASMEDC, 2009. http://dx.doi.org/10.1115/icem2009-16341.

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The Ruprechtov Natural Analogue (CZ) Programme has been focused on studying real system processes, relevant to performance assessment (PA) of sediment formations that can form the overburden of geological repository host rocks. The site has been extensively studied due to its geological constitution (granite – kaolin – clay – U mineralisation – organic matter). The presented study used Ruprechtov unique but well-described geological conditions in order to identify and characterise mobile organic matter (MOM) that can be easily released into groundwater and can influence PA relevant specie migration due to complexation/sorption reaction. The modern analytical method MALDI-TOF MS was used for characterisation. It was found that only a small fraction of sedimentary natural organic matter (NOM) from the site was easily releasable (max. 5%) as MOM, resulting in low organic substance concentration in natural groundwater. MOM amount released was decreasing with increasing NOM content. MALDI-TOF MS proved to be a useful tool to characterize organic substances, either natural ones or artificially released from natural organic matter samples. A noticeable fingerprint for all the MOM compounds analysed was found at MALDI-TOF MS spectra. This showed that MOM from the Ruprechtov site was in all cases composed of molecules with low molecular weight (under 1000 Da). As determined by the consequent geochemical analyses, despite groundwater reducing conditions MOM compounds would be mainly interacting with U(VT) in the groundwater, being present as more abundant U specie. Good correspondence of results enabled to consider the extracted humic acid HA 12/3 as a mobile organic matter fraction representative.
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Fitnawan, Eko Awan, Bjørn Holien, and Harald Nevøy. "Successful Installations and Predictable Performance of Solid Expandable Drilling Liner in Greater Ekofisk Field, Offshore North Sea." In SPE/IADC International Drilling Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/204018-ms.

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Abstract Drilling the lower overburden section in specific parts of the Greater Ekofisk Area (GEA) fields can be very troublesome. Wells in these parts may intersect shales with high gas content in the upper section (requiring high mud weight) and unstable zones with massive lost circulation risk (requiring low mud weight) near the base of the interval. These challenges have raised the need for a contingency drilling liner to "split" the section in two parts. Rather than changing the basic well design, the operator fronted the development of an 8-5/8″ expandable drilling liner with high collapse resistance for this purpose. This string provides 8.514″ post-expansion drift ID that accommodate an 8 ½″ bit size for the reservoir section, which is critical for GEA well design strategy. In the past five years, the operator has successfully installed 31 800 ft of 8-5/8″ expandable liner in 27 different wellbores with near perfect track record. The average liner length installed is 1 140 ft per wellbore, with an average installation time of 2.8 rig days. The solid expandable tubular (SET) drilling liner has been utilized both as part of the planned well design and as contingency liner. It has, on occasions, been worked down with parameters outside the stated specifications and still been successfully expanded afterwards. The 8-5/8″ expandable liner is now a proven system and has been one of the key enablers to achieve well objectives by maintaining hole size in a predictable manner. It provides a better drilling window for reservoir drilling and reservoir liner cementing compared to a conventional 7-3/4″ liner alternative. It also enables further contingency solutions in case other difficulties arise in the reservoir section. This technical paper describes how the operator in the overcame a significant geological challenge by working with an expandable pipe supplier to develop a unique size and strength of expandable liner that fits with the base case GEA well design. The paper also reviews the installation experiences, associated risks, performance, and key learnings with expandable liners.
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Shaver, Michael Alexander, Gilles Pierre Michel Segret, Denya Pratama Yudhia, Suhail Mohammed Al Ameri, Erwan Couziqou, and Adel Rahman Al Marzouqi. "A Geomechanical Model and Workflow for Calibrating Elastic Moduli and Min/Max Horizontal Stress from Well Logs in the Nahr Umr Shale." In SPE/IADC Middle East Drilling Technology Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/202204-ms.

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Abstract Thin layering and micro-fracturing of the thin laminated layers are some possible reasons for the wellbore stability problems of the Nahr Umr shale. If the drilling fluid density is too low, collapsing of the borehole is possible, and if the drilling fluid density is too high, invasion of the shale can occur, weakening the shale, making boreholes prone to instability. These effects can be semi-quantified and assessed through the development of a geomechanical model. The application of a geomechanical model of a reservoir and overlaying formations can be very useful for addressing ways to select a sweet spot and optimize the completion and development of a reservoir. The geomechanical model also provides a sound basis for addressing unforeseen drilling and borehole stability problems that are encountered during the life cycle of a reservoir. Key components of any geomechanical model are the principal stresses at depth: overburden, minimum horizontal principle stress, and maximum horizontal principle stress. These determine the existing tectonic fault regime: normal, strike-slip, and reverse. Additional components of a geomechanical model are pore pressure, unconfined compressive strength (UCS) rock strength, tilted anisotropy, and fracture and faults from image logs and seismic. Unfortunately, models used to make continuous well logging depth-based stress predictions involve some parameters that are derived from laboratory tests, fracture injection tests, and the actual fracturing of a well—all contributing to the uncertainty of the model predictions. This paper addresses ways to obtain these key parameter components of the geomechanical model from well logging data calibrated to ancillary data. It is shown how stress, UCS, and pore pressure prediction and interpretation can be improved by developing and applying models using wellbore acoustic, triple combo, and borehole image data calibrated to laboratory and field measurements. The nahr umr shale and other organic mudstone formations exhibit vertical transverse isotropic (VTI) anisotropy in the sense that rock properties are different in the vertical and horizontal directions (assuming non-tilted flatbed layering), the horizontal acoustic velocity is different from that of vertical velocity. This necessitates the building of anisotropic moduli and stress models. The anisotropic stress models require lateral strain, which as shown in the paper, can be obtained from micro-frac tests and/or borehole breakout data.
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Guo, Weijia, Yangyang Li, Baoliang Zhang, Hailong Wang, and Xizhen Sun. "Study on the Movement Law of Overburden Strata During Mining Strip Pillar with Paste." In Taishan Academic Forum - Project on Mine Disaster Prevention and Control. Paris, France: Atlantis Press, 2014. http://dx.doi.org/10.2991/mining-14.2014.7.

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Landry, Christopher J., Bruce S. Hart, and Maša Prodanović. "Comparison of Wireline Log and SEM Image-Based Measurements of Porosity in Overburden Shales." In Unconventional Resources Technology Conference. Tulsa, OK, USA: American Association of Petroleum Geologists, 2020. http://dx.doi.org/10.15530/urtec-2020-3141.

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Zhang, Hui, Jianfeng Yao, Xiang Li, and Kai Zhao. "Maximising the Value of Multi-Sensor Streamer Data via MAZ Processing." In International Petroleum Technology Conference. IPTC, 2021. http://dx.doi.org/10.2523/iptc-21435-ms.

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Abstract The North West Shelf of Australia contains a late Paleozoic to Cenozoic sedimentary succession, which attains a thickness of over 10 km and is dominated by Triassic to Lower Cretaceous sediments. The deeper plays exist at multiple stratigraphic levels including oil-prone Jurassic sediments and faulted gas-prone Triassic sediments. The area has been proven difficult as far as seismic imaging is concerned, particularly over the Madeline trend. The presence of a hard, rugose water bottom, strong reflectors beneath the water bottom, and shallow Tertiary carbonates make the Dampier Sub-basin vulnerable to multiple contamination, amplitude distortion, lower signal-to-noise ratio (S/N) and unreliable AVO response. Poor seismic quality in the data has been a significant barrier to reducing exploration risk. In the 1990s, East Dampier (1992, blue polygon in Figure 1) and Keast (1997, yellow polygon in Figure 1) seismic data were acquired in East-West and North-South directions respectively, in an effort to better understand the impact from the shallow complex overburden. To address these challenges, the Demeter survey was acquired in 2003 (black polygon in Figure 1) with a denser acquisition grid. The overall seismic quality was improved, but the results still contained a significant level of residual multiples. Later, the Fortuna survey, the most comprehensive multi-sensor seismic survey on the North West Shelf of Australia to date, was acquired in 2014 with the aim to provide better subsurface imaging (pink polygon in Figure 1) from different acquisition perspectives. The data was processed with advanced processing technology, including shallow water demultiple, deghosting and high definition tilted orthorhombic velocity model building (Birdus et al., 2017). However, the final results were still suffering from a number of challenges, specifically: 1) strong residual multiple in near offsets, 2) low S/N ratio, particularly at reservoir level, and 3) inconsistency from near to far stack resulting in unreliable AVO. In this paper, the Dixon area (green polygon), considered as the most challenging area in the Dampier Sub-basin, was chosen as the testing area for our work. By integrating high-end imaging technology, for example dual-sensor deghosting, multi-survey surface related multiple elimination (MAZ-SRME), and multi-azimuth processing (MAZ stack), we will illustrate how we have overcome many of these imaging challenges.
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Reports on the topic "Low overburden"

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Maps showing geologic terrane, drainage basins, overburden, and low flow of streams in Fairfax County and vicinity, Virginia. US Geological Survey, 1985. http://dx.doi.org/10.3133/i1534.

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