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76th EAGE Conference and Exhibition 2014
- Conference date: June 16-19, 2014
- Location: Amsterdam, Netherlands
- Published: 16 June 2014
1001 - 1028 of 1028 results
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Shale Gas in Place Calculation for a Single Well
Authors W. Machowski and G. ZabekSummaryThe aim of this study is to estimate total gas-in-place volumes for the Lower Paleozoic shale rocks, in part the Baltic Basin of northern part of Poland. For one of the projected horizontal well in Poland, the investigation was carried out. Based on published and literature date the authors built 3D static model which consist structural and parametric data needed for volumetric calculation. The input data include porosity, density, water saturation. The calculations for Polish conditions were compared with production data from North America and China. The analysis were provided for four examples. Based on available data and provided analysis of gas reserves for a single, depending on the fracking results, that the GIIP are changing. The quality and number the input data used to volumetric calculations plays a very big difference on gas resources. Graphics comparison between minimal Canadians and Polish, maximal Chinese (Longmaxi) and USA (Barnett Shale) shows statistical data.
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How Can the South Atlantic Spreading Rate Vary so Quickly?
By L. ColliSummaryThe spreading history of the South Atlantic Ocean is characterized by large spreading rate variations over short (10–15 Myrs) timescales, with fast spreading in Late Cretaceous and Eo-Oligocene. These variations are kinematically well constrained, but their dynamic origin is still unknown. Using simple tectonic force balance models and fluid-dynamic scaling arguments we show that the spreading rate variations require a significant decoupling from the lower mantle buoyancy distribution via a thin and low-viscosity asthenosphere. Moreover, we show that basal drag due to Poiseuille flow in the asthenosphere is a major component of the tectonic force balance. An unsteady asthenospheric flow due to temporal changes in regional pressure gradients can thus explain the spreading rate history, but also implies a correlation of horizontal and vertical motions: the lateral pressure gradients that drive the asthenospheric flow are also bound to cause a conspicuous non-hydrostatic topography gradient across the basin. We find that this prediction from our models agrees with a broad range of geologic and geophysical observations of the South Atlantic region, including episodes of passive margin uplift, regional basin reactivation and magmatic activity.
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Using of the Optical Fiber Technology in Oil and Gas Downholes
More LessSummaryThe theme of the research is devoted to the optical fiber technology during the investigation of the oil and gas downholes while WO operations. This article describes the workings of an optical fiber temperature sensing system. It is the review of the optical fiber technology during the investigation of the oil and gas downholes while WO operations that shows how knowledge of the main principles of the thermal behavior of oil or gas in wellbores helps geophysicists conclude what processes are exactly happening downhole. Optical fiber technology was used to diagnose well defects while WO operations on several oil deposits in Perm region. There are some results of the carried out works based on the technology described above.
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3D Subsurface Temperature Model of Europe for Geothermal Exploration
Authors J. Limberger and J.D. van WeesSummaryFor the assessment of geothermal resources in Europe we constructed a digital 3D temperature model of the European crust and sedimentary basins, incorporating publicly available temperature data. Using European crustal thickness models and indirect parameters such as surface heat flow measurements, temperatures were calculated for regions where data are scarce.
Our temperature model of Europe has a horizontal grid resolution of 10×10 km and extends to a depth of 10 km below ground level. The model covers Europe up to the Russian border and includes Turkey and Iceland.
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Synthetic Diagenesis - The Key to Carbonate Systems in Basin Modelling
Authors A. Mangione, H. Lewis, S. Geiger, C. van der Land, R. Wood and G. CouplesSummaryBasin modelling tools are widely used to predict reservoir charging but, unfortunately, their application to carbonate reservoirs is far from straightforward. For carbonates, the relationships between porosity/effective stress/depth, must be addressed before a reliable basin model can be produced. We propose using a synthetic diagenesis approach, where Pore Architecture Models (PAMs) are used to generate representative porosity values for the different diagenetic (backstripped) stages that are recognised from cores or thin sections. The synthetic diagenesis approach is then used to inform more conventional basin modelling. The viability of this method is the topic of this contribution.
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Paleogeographic Reconstruction of Northern Caribbean Region from Late Cretaceous to Recent
Authors S.S. Ahmad and A. EscalonaSummaryUsing a regional data base of around 600 2D seismic lines, data from 166 wells and detailed field guides describing the geological history of Cuba, Hispaniola, Nicaraguan rise and continental highlands of Central America, task was to make the paleogeography of the Northern Caribbean. Paleogeographic reconstruction is for seven different time intervals, beginning with Late Cretaceous and running to the Recent. Moreover, these maps constructed and updated by PaleoGIS software Previously Paleogeographic maps for seven different time intervals (late Cretaceous to recent) were prepared, describing tectonic controls on sedimentation, for the Northern and Eastern offshore South America.
Paleogeographic maps for Northern Caribbean region describes the effects of collision between Caribbean Plate in Northern and western part with Bahama platform and Chortis block respectively, including changes in positions of coastlines and inferred paths of major river systems draining from continental highlands of Cuba, Hispaniola, Jamaica and Central America to adjacent areas.
Paleogeographic maps are critical for petroleum exploration in Northern Caribbean region, in particular for the distribution of source rocks and high quality reservoir rocks.
Despite, the presence of oil and gas fields in Northern Caribbean region, several oil and gas shows reported from different exploratory wells drilled in Northern Caribbean Region.
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Sedimentary Sequence and Evolution of Channel-Lobe in Li Wan Deep-water Areas, Baiyun Sag, Northern South China Sea
By H.R.L LiuSummaryDeep-water channels and lobes have become important exploration targets in Baiyun sag. Channels in LiWan deep water areas of Baiyun sag shows transformation on the morphology from type ‘V’ to type ‘U’ which illustrates the main channels’ migration. Recent researched has revealed the sedimentary models of Baiyun sag, namely the model of ‘delta front’ to ‘deep-water fan’. Furthermore, this paper classifies Zhujiang formation as one sequence which can be subdivided as LST, TST and HST. In early LST period, the morphology of channels are almost type ‘V’ and mainly controlled by erosion effect. Under the relative see level decreasing quickly, lobes appear progradation. In middle LST period, morphology of channels transforms from type ‘V’ to type ‘U’. With the relative sea level decreasing smoothly, lobes move with the channels and synchronously appear aggradation. In the later LST period, relative sea level and accommodation space increases quickly. Morphology of channels transforms from type ‘U’ to type ‘W’ and channels gradually migrate to the source direction. Meanwhile, sediment scope of lobes reduces and lobes mainly appear retrogradation. In TST and HST period, relative sea level continues to rise until over the shelf slope break belt, but gravity flow of channels relatively weakens.
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Kerpini Fault Controlled Sedimentation in Kerpini Fault Block, Greece
Authors R.A. Syahrul, C. Townsend, A. Escalona and A. DahmanSummarySedimentary rocks in Kerpini Fault Block can be distinguished into three main groups, from the oldest to youngest as the following: 1) Fluvial Sandstone-Conglomerate, 2) Alluvial Fan Conglomerate, and 3) Late Fluvial Sandstone-Conglomerate.
The first and second groups were deposited in the early syn-sedimentary phase while the third group in the late syn-sedimentary phase.
The general dip directions of the syn-fault deposits (southeast) is slightly oriented towards the maximum throw of the fault. The constant dip for these sediments can be explained by the location of reverse drag of the fault that far north away from the Kerpini fault.
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Inversion Structures in a Foreland Area - Seismic Examples from the Adriatic Sea - Italy
Authors P. Pace, V. Scisciani, D. Margiotta, F. Calamita, D. Rowlands, N. Hodgson and P. EsestimeSummaryThe Adriatic represents a foreland area surrounded by three distinct fold-and-thrust belts: the Apennines to the west, the Southern Alps to the north, and the Dinarides to the east. A NW-SE-trending compressional ridge (Mid-Adriatic Ridge) extending from more than 100 km affects the middle zone of the Adriatic foreland. The interpretation of recently reprocessed seismic data from the Italian sector of the Adriatic offshore reveals that most of the thrust-related folds belonging to the Mid-Adriatic Ridge are positive inversion structures. On seismic, they typically appear as asymmetric inversion anticlines developed by the Neogene reverse reactivation of inherited Mesozoic graben and half-graben basin-bounding normal faults. Some of these structures are undrilled and they may potentially be attractive carbonate targets.
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The Evolution of Reverse Faults in Forced-fold Analogue Experiments Using Wet Clay
Authors A. Druga, Z. Schleder and C. KrezsekSummaryThe main objective of this project is to study the development and the architecture of extensional forced folds. Such structures usually develop above reactivated extensional basement fault. It is important to understand the evolution of reverse folds as they can trap hydrocarbons.
We used wet kaolin clay models to observe the development of forced folding and the associated faults. Many of the features seen in the analogue models can be identified also on seismic reflection data.
Therefore, the analogue experiments were successfully used as a template to interpret the Jurassic extensional fault system from the Moesian Platform, Southern Romania.
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Moving Audio Magnetotelluric (AMT) Test Measurement
Authors C. Shan and L.B. PedersenSummaryThis study is to test the idea of the developed Audio Magnetotelluric (AMT) method by placing the magnetic sensors in the air instead of burying in the gound. Five channels electric and magnetic fields are measured. The data acquistion time for each station is around 15 minutes and is enough to cover the frequency range from 30 to 300 Hz. Normal MT processing techniques are used for the data collected by the developed method to yield frequency domain transfer functions. The data quality from the test measurement is rather good with smooth apparent resistivity and phase. The developed method is proved to have several supriorites than the normal AMT measurement, and is applicable to shallow depth investigation efficiently in the future.
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Preliminary Paleomagnetic Results from the Calimani Mountains, Romania
Authors D. Bugheanu, D. Dimofte and C.G. PanaiotuSummaryPaleomagnetic studies have been used for a long time to investigate the evolution of the magnetic field but also to obtain information about structural deformation, tectonic movements, magnetic mineralogy or geochronology. The studied area is the first magmatic episode from the Calimani-Gurghiu-Harghita volcanic chain. This volcanic arc that resulted once with the formation of the Carpathian orogen by the collision of the Alcapa and Tisia blocks with the European continent. The paper presents the polarity data obtained after the measurement of two pilot samples using the alternating field demagnetization (AF) and thermal demagnetization methods. Some samples revealed to be unsuitable for analysis and for further measurements, so the reason of their exclusions is discussed. The polarity distribution correlates with the K-Ar ages and matches with Middle-Late Miocene Polarity Time Scale
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The Analysis of Seismic Response Characteristics of Tight Thin Inter-layer Reservoirs
More LessSummaryAnalysis of the seismic response characteristics has been one of the hottest topics of reservoir prediction. However, seismic response of tight thin reservoirs is much more complicated than normal reservoirs. The author construct different kinds of forward models for tight thin inter-layer by collecting parameters from well and rock physical parameters of a gas field with a lot of tight thin reservoirs. And then use the seismic data to analyse pre-stack seismic response. The studies show that the seismic response is complicated in thin layers especially for inter-layer. The pre-stack seismic response is different from conventional AVO type and the post-stack seismic section also has its own features. The seismic responses of dry and gas-bearing layers process significant difference. The analysis for tight thin reservoirs’ response will provide more detailed information to guide reservoirs prediction.
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Impact of Fracturing and Drainage-Wide Production on Tight Gas Reservoir
Authors M.H. Farooqui, M.S. Qamar and O. AhsanSummaryHydraulic fracturing has been established as perhaps the most compelling and attractive production enhancement technique for both conventional and tight gas reservoirs. However number of formation evaluation considerations must be accounted such as the location and distance of water and hydrocarbon contacts, layering and other barriers which could limit achievable production results.
Fracturing increases well potential as well as recovery when compared to un-fractured well. Orientation of a fractured well in relation to other wells plays a significant role in optimizing rate and recovery. The flow in a fractured formation is linear and its duration will increase as the stimulation level increases. At the limit, only linear flow is seen for a fully penetrating fracture in pseudo steady state well drainage, with adequate fracture conductivity.
This study focuses on fracture geometry, number of fractures, fracture spacing, half length, well configuration, well location, the impact of fracture geometry on enhanced recovery and aspect ratio.
On the basis of study (within the study limitations), we conclude that • Fractured horizontal wells are more attractive in tight gas reservoirs than vertical fractured wells and • Use of rectangular patterns in field development combined with hydraulic fracturing creates the potential for larger JDs and recovery.
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Multi-Data Reservoir History matching of Crosswell Seismic, Electromagnetics and Gravimetry Data
More LessSummaryReservoir engineering has become of prime importance for oil and gas field development projects. With rising complexity, reservoir simulations and history matching have become critical for fine-tuning reservoir production strategies, improved subsurface formation knowledge and forecasting remaining reserves. The sparse spatial sampling of production data has posed a significant challenge for reducing uncertainty of subsurface parameters. Seismic, electromagnetic and gravimetry techniques have found widespread application in enhancing exploration for oil and gas and monitor reservoirs, however these data have been interpreted and analyzed mostly separately rarely utilizing the synergy effects that may be attainable. With the incorporation of multiple data into the reservoir history matching process there has been the request knowing the impact each incorporated observation has on the estimation. We present multi-data ensemble-based history matching framework for the incorporation of multiple data such as seismic, electromagnetics, and gravimetry for improved reservoir history matching and provide an adjoint-free ensemble sensitivity method to compute the impact of each observation on the estimated reservoir parameters. The incorporation of all data sets displays the advantages multiple data may provide for enhancing reservoir understanding and matching, with the impact of each data set on the matching improvement being determined by the ensemble sensitivity method.
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New Idea in Original Oil Water Contact (OOWC) Reconstruction for Mature Oil Field - Example from Terbang Field
Authors E.H. Sihombing and J. SetyowiyotoSummary‘Terbang’ field is located in Central Sumatra Basin and discovered in 1971 with 49 wells in 14 oil reservoirs where 141,407 MMSTB oil has been booked for the OOIP (2007). The RF in still reach 34.36 % (Nov, 2013) & WC from all the wells is 97.6%: an indication of overestimated OOIP where Boi, porosity (Φ) and Sw are not seems to produce the overestimation. The overestimation comes from the net pay volume where the OOWC as the boundary is never addressed carefully. For that, this paper integrates a new methodology to produce a better OOWC assessment by consider the depletion history (1971-recent). A new idea that be purposed here is to utilize data that rarely be used in OOWC interpretation: rock sample oil stain from 2159 side well core samples that integrated with log & swab test and completion data. This integration produce reservoir depletion history that used to reconstruct the original condition and OOWC position before first well drilled. Result: almost all the reservoirs multiple and complex OOWC controlled by compartmentalization and spill point. These never been seen before due to limited of seismic resolution, means this methodology shows a better result than the previous study result.
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Migration and Alteration Processes in Barents Sea Oils and Condensates - A Geochemical Appraoch
Authors B. Lerch, D.A. Karlsen and D. DugganSummaryPetroleum systems in the Barents Sea were affected by repeated uplift and erosion processes which had impact on the distribution, alteration and composition of petroleums as well as on cap-rock properties. An important hydrocarbon fraction when evaluating post-emplacement alteration processes such as biodegradation, evaporative fractionation and long-distance migration are light hydrocarbons (LHC), since they make up a significant volume of oils/condensates. This study sheds light on oil-oil and oil-condensate relationships from the Hammerfest Basin and Loppa High. Analyzed condensates are altered by evaporative fractionation but do not show signs of biodegradation. Medium to high toluene contents indicate locally derived LHC with short migration distance. However, analyzed oils show clear indication of biodegradation and some being also altered by evaporative fractionation. Low content of water-soluble aromatic HC imply long-distance migrated LHC. Medium to high gas to oil ratios (GOR) for central basin samples indicate tight sealing cap-rocks, whereas samples with low GOR occur at the northern and southern tectonized basin margins, suggesting leaking cap-rocks. Tight cap-rocks might play a crucial role in the distribution as they hold back gas/condensates and favor the remigration of liquid petroleums, whereas leaking cap-rocks hold back oil and allow the gas/condensate to leak.
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Statistical Analysis of Microelement Trends in Graptolitic Argillite, Northern Estonia
Authors O.P. Nzekwe, R. Lehné and O. LenzSummaryThis work presents a statistical analysis of microelement trends in graptolitic argillite (oil shale variety) in northern Estonia with respect to the spatial extent and compositional dynamics of the shale layers. Graptolite argillite is characterized by significant amounts of microelements (U, Mo, Zn, etc.). Statistical analysis namely, correlation analysis, principal component analysis (PCA) and canonical correspondence analysis (CCA) indicates other prevailing trends. PCA suggests microelements associations while CCA shows the relationship between microelements and “environmental” factors. These trends possibly indicate variable composition of organic matter/mineral particles in graptolitic argillite in northern Estonia.
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Organic Geochemistry, Burial History and HC Generation Modelling of Upper Cretaceous Sediments in the Chad (Bornu) Basin
Authors A.K. Adegoke and W.H. AbdullahSummaryThe Upper Cretaceous Gongila and Fika Formation sediments, which are believed to be the major source rocks in the Chad (Bornu) Basin, were analysed using organic geochemistry and petrology. The total organic carbon (TOC) contents of the sediments range from 0.42 to 4.90%. The samples analysed have vitrinite reflectance in the range of 0.58 – 1.39 % Ro and pyrolysis Tmax in the range of 429 – 475 oC indicate that the Gongila and Fika sediments contain mature to late mature organic matter. Moderate oil-generating potential is anticipated from the sediments with fairly high hydrogen indices (150 – 250 mg HC/g TOC). This is supported by their Py-GC (S2) pyrograms with n-alkane/alkene doublets extending beyond n-C30. The sediments are dominated by Type II and Type III kerogen and are thus considered oil and gas prone (mainly gas). One-dimensional basin modelling was performed to analyse the hydrocarbon generation and expulsion history of the Upper Cretaceous sediments in the Chad (Bornu) Basin based on the reconstruction of the burial/thermal maturity histories. This is to improve our understanding of the of hydrocarbon generation potential of the source rocks. Calibration of the model with measured vitrinite reflectance (Ro) and borehole temperature data reveals that the present-day heat flow in the Chad (Bornu) Basin varies from 55.0 mW/m2 to 60.0 mW/m2 and paleo-heat flow value at approximately 68 mW/m2. The source rocks of the Gongila and Fika Formation are presently at a stage of oil, condensates and gas generation with thermal maturity ranging from 0.58% to 1.39% Ro. The modelled burial history also suggest that maximum burial occurred in the late Miocene and that erosion might have been the cause of the thinning of the Tertiary sediments in the present time.
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Molecular Composition of Abu Gabra Organic-rich Sediments in the Fula Sub-basin, Muglad Basin (Sudan)
Authors Y. M. Makeen, W. Hasiah Abdullah and M. Hail HakimiSummaryThe Abu Gabra sediments possess a very good oil-generative potential as suggested by high amounts of organic matter with high TOC values in the range of 1.3 to 8.3 % that is dominated by Type I and Type II oil-prone kerogens. This is indicated by a significant presence of alginite and amorphous organic matter and supported by HI values in the range of 287–865 mg HC/ g TOC. Vitrinite reflactence (0.60–0.72%Ro) and Tmax values (430–438oC), and biomarker thermal maturity parameters indicate that the Abu Gabra sediments have entered an early mature of oil window. The predominance of even-over-odd (n-C14 to n-C20) with significant presence of waxy n-alkanes (+n-C23) and with isoprenoids Pr/Ph ratios in the range of 1.17–2.51, indicating that these sediments were deposited in a suboxic, lacustrine environment that received both algal/bacterial and terrigenous organic matter input.
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Investigation and Model Correlations of Vp/vs and Porosity of Carbonates
Authors J. Pupos and N. GegenhuberSummaryMany articles deal with the topic of compressional and shear wave velocity of carbonate rocks and their correlation as well as model correlations. This paper will show the first results of compressional and shear wave velocity measurements and the calculations using the model of Kuster & Toksoez. Different carbonates of Austria were measured in the laboratory to determine their porosity as well as their compressional and shear wave velocity (dry). Two different measurements were executed to determine the effective porosity of samples (helium porosity and principle of Archimedes). Some samples have bigger helium porosity than the porosity that derived using the buoyance method. It was assumed that there are more pores with a radius under the radius of a water molecule, while they are big enough to let a helium molecule through.
Using the measured compressional/shear wave velocity and the effective porosity the inclusion model that developed by Kuster and Toksoez was accomplished for the dry samples. This model is limited to low porosity our result was sufficient. The penny shaped cracks with different aspect ratio (0.005–0.5) were used. It was observed, that different aspect ratios needed to be applied for different lithologies.
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High Resolution Stratigraphy and Reservoir Heterogeneity of Khartam Member of Khuff Formation from Outcrop, Saudi Arabia
Authors M. Osman, O. Abdullatif, M. Al-Farhan, H. Eltom and M. BashriSummaryThe Permian-Triassic Khuff Formation is the most prolific for natural gas production in the Middle East. Understanding the Khuff reservoir heterogeneity is important to enhance the hydrocarbon production. Integrated study including sedimentology, stratigraphy and digital outcrop modelling is applied here. The studied Upper Khartam Member outcrop is an analog for the Khuff-A reservoir in the subsurface. Ten lithofacies were identified from the whole samples collected from the outcrop. These lithofacies were interpreted to have been deposited in 1) marine transgression, 2) foreshoal, 3) shoal complex, 4) shoal fringes, 5) back shoal, 6) tidal flat and 7) supratidal flat. The composite sequences of the Upper Khartam Member consist of five high frequency sequences. The results of this study also showed a distinct five potential reservoir units in the second and third high frequency sequences. The digital modelling been applied to these sequences to delineate the reservoir units in a more realistic and high precision environment. Outcomes of this study can be utilized to decrease uncertainty on reservoir continuity and architecture and lateral facies continuity within interwell spacing in equivalent Khuff reservoir models in the subsurface. Consequently this might enhance understanding and prediction of reservoir quality in the subsurface.
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Steady and Unsteady Flow in Permeable-fractured Carbonate Reservoirs
Authors L.C. Vasquez Cardenas and N.S. GolikovSummaryThis paper will discuss and suggest possible applications for the results of the aforementioned processes on a larger scale, utilizing systematical approaches with the scales of evaluation from core to reservoir, and adaptations for several hydrodynamic models. It also explains the impact of wettability and capillary forces during the drainage process between matrix and fractured structures. Furthermore, through the examination of pressure gradients, effective viscosities, and yield-shear stresses, a complete comprehension of reservoir dynamics will be greatly facilitated.
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A Modelling Study Of Broadband Seismic Wave Propagation In A Deep Mine
Authors R. Saleh and B. MilkereitSummaryUnderstanding the propagation of seismic waves in a presence of very strong elastic contrasts, such as topography, tunnels and ore-bodies is still a challenge. Safety in mining is a major concern and seismic monitoring is the main tool here. For engineering purposes, amplitudes (peak particle velocity/acceleration) and travel times of seismic events (mostly blasts or microseismic events) are critical parameters that have to be determined at various locations in a mine. These parameters are useful in preparing risk maps or to better understand the process of spatial and temporal stress distributions in a mine. Simple constant velocity models used for mine monitoring, cannot explain the observed complexities in scattered seismic waves. In hard-rock environments modelling of elastic seismic wavefield require detailed 3D petrophysical, infrastructure and topographical data to simulate the propagation of seismic wave with a frequencies up to few kilohertz. In this study, the effects of strong elastic contrasts on the propagation of broadband seismic waves will be illustrated using 2D/3D finite difference method.
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Steam Actuated In-Situ Combustion - An Advancement in EOR
By G. SinghSummaryIn-situ combustion (ISC) is used widely but with limited field success due to vast capital costs, operating expenses, flue gas emissions, water treatment and handling costs are associated with it. There is a need to optimize efficiency of recovery process by lowering air requirement, environmental impact, and costs of technique. As the principle recovery mechanisms for combination of steam and combustion processes are steam distillation, viscosity reduction and thermal expansion of oil. Therefore steam extracts lighter hydrocarbon fractions, so that the residue becomes heavier, mixing of distilled component with initial oil results in lighter produced oil. Thus the use of steam in combination with air reduces air requirement with low emission of flue gases during the process. Three important mechanism on which thermal recovery methods depends are thermal expansion, viscosity reduction and steam distillation.
Combustion tube run experiments were carried out to obtain the information about the reservoir and to find the combustion parameters. Combination of ISC and steam flooding increases the life of project and at the same time minimizes emission of flue gases during process and thus improves recovery.
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Optimization of Polymer Flooding Design for Maximizing Economic Profit under Bottom-Water Condition
By K.H. ParkSummaryBottom-water aquifer has been considered as an unfavourable condition for polymer flooding. It causes the excessive water production which might cause the abandonment of the operation. A number of researches have focused on the identification and remediation of such problems. Among suggested solutions, the polymer injection has been known as the effective treatment to increase the profits. For better performance and maximum profit, the operating conditions of polymer flooding regarding the location of injection well and the concentration of polymer solution need to be thoroughly investigated. In this work, numerical simulations were used to examine the effects of the conditions on performance of polymer flooding under bottom-water aquifer oil reservoir.
This work describes a fully integrated evaluation ofpolymer Enhanced Oil Recovery project applied on the reservoir with strong bottom-water aquifer. The comparison was made regarding the oil recovery, water cut, and economic feasibility of polymer flood to find the optimal design of well location and polymer concentration. The NPV has been used to evaluate economics of the work. Not only the operating conditions, but also geological properties of the reservoir have uncertainties. Considering uncertainties, the effects of undetected geological event on the NPV of polymer flooding is analysed by sensitivity analysis.
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Improved Recovery by Optimizing Water Flooding - An Experimental Approach
Authors A. Chaturvedi and G. SinghSummarySince the inception of water flooding it has been used to improve recovery from oil reservoirs mainly light and medium oil and has very high success rate than other methods due to high recovery factor and low costs associated with it. Clay minerals are present as rock matrix in sandstone reservoir and adversely affect during water flooding as they swell and decrease the porosity and block the pore throat thus resulting in reduced production. An experimental study was done to determine formation damage due to clay swelling, and to identify a cost effective clay stabilizer to be used in the injection water. The study included performing core flood experiments using sandstone reservoir cores, analysing the effects of stabilizer type and concentration on permeability of core in detail and selecting critical salt concentration, below which there is loss of permeability occurs. Based on the data obtained, analysis of change in porosity and permeability was done. With the help of data obtained, clay swelling effect has been seen while flooding with distilled water; it reduces by the use of clay stabilizer. At the same time use of brine in place of distilled water increases recovery efficiency of water flooding, thus improving recovery.
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Extracting Quality Factor by Spectral Simulation Method
More LessSummaryQuality factor Q reflects the strength of seismic wave attenuation, and it is an important parameter on hydrocarbon detection and reservoir description. The article selects the appropriate function to fit the seismic spectrum. Combined with the energy attenuation law, we find that the spectral fitting coefficient can be divided into three categories: related to the absorption and attenuation; associated with the energy attenuation of non-frequency (e.g., diffusion, reflection, transmission, etc.); and unrelated to the energy attenuation. According to the fitting coefficients related to the absorption and attenuation, we can calculate the quality factor Q from inversion. Model test without noise shows that extracting Q value from fitting coefficients can reflect the Q values trend of formation. Under the condition of weak noise, based on the different variation rules of three kinds of fitting coefficients, firstly, we calculate the expectation of fitting coefficients that is unrelated to the attenuation. Secondly, take a two-order fitting for the rest of the coefficients to improve the inversion precision of the formation parameters. The results of model tests confirm the theoretical feasibility of this method. It gets good application effect after inverse Q filter.
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