Coupled finite‐element simulation of injection well testing in unconsolidated oil sands reservoir     

Bin Xu  Ron C.K. Wong 《国际地质力学数值与分析法杂志》2013,37(18):3131-3149

This paper presents a finite‐element (FE) model for simulating injection well testing in unconsolidated oil sands reservoir. In injection well testing, the bottom‐hole pressure (BHP) is monitored during the injection and shut‐in period. The flow characteristics of a reservoir can be determined from transient BHP data using conventional reservoir or well‐testing analysis. However, conventional reservoir or well‐testing analysis does not consider geomechanics coupling effects. This simplified assumption has limitations when applied to unconsolidated (uncemented) oil sands reservoirs because oil sands deform and dilate subjected to pressure variation. In addition, hydraulic fracturing may occur in unconsolidated oil sands when high water injection rate is used. This research is motivated in numerical modeling of injection well testing in unconsolidated oil sands reservoir considering the geomechanics coupling effects including hydraulic fracturing. To simulate the strong anisotropy in mechanical and hydraulic behaviour of unconsolidated oil sands induced by fluid injection in injection well testing, a nonlinear stress‐dependent poro‐elasto‐plastic constitutive model together with a strain‐induced anisotropic permeability model are formulated and implemented into a 3D FE simulator. The 3D FE model is used to history match the BHP response measured from an injection well in an oil sands reservoir. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Water flux measurement and prediction in young cashew trees using sap flow data     

Philip G. Oguntunde  Nick van de Giesen 《水文研究》2005,19(16):3235-3248

Measurements of sap flow, meteorological parameters, soil water content and tension were made for 4 months in a young cashew (Anacardium occidentale L.) plantation during the 2002 rainy season in Ejura, Ghana. This experiment was part of a sustainable water management project in West Africa. The Granier system was used to measure half‐hourly whole‐tree sap flow. Weather variables were observed with an automatic weather station, whereas soil moisture and tension were measured with a Delta‐T profile probe and tensiometers respectively. Clearness index (CI), a measure of the sky condition, was significantly correlated with tree transpiration (r² = 0·73) and potential evaporation (r² = 0·86). Both diurnal and daily stomata conductance were poorly correlated with the climatic variables. Estimated daily canopy conductance g_c ranged from 4·0 to 21·2 mm s⁻¹, with a mean value of 8·0 ± 3·3 mm s⁻¹. Water flux variation was related to a range of environmental variables: soil water content, air temperature, solar radiation, relative humidity and vapour pressure deficit. Linear and non‐linear regression models, as well as a modified Priestley–Taylor formula, were fitted with transpiration, and the well‐correlated variables, using half‐hourly measurements. Measured and predicted transpiration using these regression models were in good agreement, with r² ranging from 0·71 to 0·84. The computed measure of accuracy δ indicated that a non‐linear model is better than its corresponding linear one. Furthermore, solar radiation, CI, clouds and rain were found to influence tree water flux. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

Geochemistry and origin of albite gneisses,northeastern Adirondack Mountains,New York     

Philip R. Whitney  James F. Olmsted 《Contributions to Mineralogy and Petrology》1988,99(4):476-484

Albite gneisses containing up to 8.7 percent Na₂O and as little as 0.1% K₂O comprise a significant part of the Proterozoic Lyon Mountain Gneiss in the Ausable Forks Quadrangle of the northeastern Adirondacks, New York State. Two distinct types of albite gneisses are present. One is a trondhjemitic leucogneiss (LAG) consisting principally of albite (Ab95–Ab98) and quartz with minor magnetite and, locally, minor amounts of amphibole or acmiterich pyroxene. LAG probably originated by metamorphism of a rhyolitie or rhyodacitic ash-flow tuff with A-type geochemical affinities, following post-depositional analcitization in a saline or saline-alkaline environment. The other type is a mafic albite gneiss (MAG) containing albite and pyroxene along with 0–45 percent quartz, minor amphibole, and titanite. MAG locally displays pinstripe banding and contains albite (Ab98) megacrysts up to 5 cm across. Its precursor may have been a sediment composed of diagenetic analcite or albite, dolomite, and quartz. Both types of albite gneiss are interlayered with granitic gneisses (LMG) of variable composition derived from less altered tuffs. A potassium-rich (up to 9.7% K₂O) microcline gneiss facies may have had a protolith rich in diagenetic K feldspar. We propose that the albite gneisses and associated granitic gneisses are the granulite-facies metamorphic equivalent of a bimodal, dominantly felsic, volcanic suite with minor intercalated sediments, probably including evaporites. The volcanics were erupted in an anorogenic setting, such as an incipient or failed intracontinental rift. Deposition took place in a closed-basin, playa lake environment, where diagenetic alteration resulted in redistribution of the alkalis and strong oxidation.  相似文献   

»Late Jurassic« petroleum geology of the Dutch Central North Sea Graben     

Th. E. Wong  Th. H. M. van Doorn  B. M. Schroot 《International Journal of Earth Sciences》1989,78(1):319-336

The Callovian to Ryazanian (late Middle Jurassic to earliest Cretaceous; here referred to as »Late Jurassic«) sediments of the Dutch Central North Sea Graben, comprising the Central Graben and Scruff Groups, form several potential reservoirs. Source rocks are present within both these groups and the Carboniferous and Late Triassic-Early Jurassic.The structural development of the area is illustrated by a number of cross-sections. A structural subdivision has been made into platform, intermediate platform, outer graben, and inner graben. The complex history of rifting, wrench-faulting, halokinesis, and structural inversion strongly influenced the palaeogeography and ensuing sandstone developments. A few selected burial-history plots are presented as examples of the relationship between the structural subdivision and the hydrocarbon potential of the area.

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Zusammenfassung Die Sedimente des Callov bis zum Ryazan (oberer Mitteljura bis unterste Kreide, hier als »Oberjura« bezeichnet) des zentralen niederländischen Nordsee-Grabens, der den Zentralgraben und die Scruff-Gruppe umfaßt, stellen mehrere potentielle Erdölspeichergesteine dar. In jeder dieser beiden Gruppen sowie im Karbon und von der Obertrias bis zur Unterkreide existieren Speichergesteine.Die strukturelle Entwicklung des Gebietes wird anhand mehrere Profile veranschaulicht. Außerdem schien eine Untergliederuntg in Plattform, Zwischenplattform, äußerer sowie innerer Graben sinnvoll. Die komplexe Entwicklungsgeschichte, die durch Riftingphasen, Wrench-Tektonik, Halokinese und Strukturinversion bestimmt wurde, hat die Paläogeographie und die resultierende Sandsteinbildung intensiv beeinflußt. Eine Anzahl ausgewählter Darstellungen der Geschichte der Sedimentüberlagerung dienen als Beispiele für den Zusammenhang zwischen den strukturell bestimmten Untergruppen und dem Kohlenwasserstoffpotential des Untersuchungsgebietes.

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Résumé Dans le secteur néerlandais du Graben Central de la Mer du Nord, plusieurs réservoirs potentiels sont constitués par les sédiments calloviens à ryazaniens (ensemble allant du sommet du Jurassique moyen au Crétacé inférieur et désigné ici par «Late Jurassic»). Ces sédiments comprennent le groupe du Graben central et le groupe de Scruff. Des rochesmères existent dans chacun de ces deux groupes ainsi que dans le Carbonifère et dans la série Trias terminal-Eojurassique.La constitution structurale de cette région est illustrée par une série de coupes. On distingue, au point de vue structural: une plate-forme, une plate-forme intermédiaire, un graben externe et un graben interne. L'histoire géologique complexe, avec ses processus de rifting, de décrochement, d'halokinèse et d'inversion structurale, s'est répercutèe de manière significative sur la paléogéographie et, par voie de conséquence, sur l'extension des faciès arénacés. Quelques reconstitutions de l'histoire sédimentaire sont présentées à titre d'exemple de manière à illustrer la relation entre les unités structurales et le potentiel en hydrocarbure de la région.

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Observations of mine seismicity in the eastern Wasatch Plateau,Utah, U.S.A.: A possible case of implosional failure     

Ivan G. Wong  James R. Humphrey  Janet A. Adams  Walter J. Silva 《Pure and Applied Geophysics》1989,129(3-4):369-405

In the summer of 1984, a three-dimensional, high-resolution microearthquake network was operated in the vicinity of two coal mines beneath Gentry Mountain in the eastern Wasatch Plateau, Utah. During a six-week period, approximately 3,000 seismic events were observed of which the majority were impulsive, higher frequency (>10 Hz), short duration (<2–3 sec) events probably associated with the caving of the roof from a longwall operation. In contrast, 234 of the largest located events appeared to occur predominantlybeneath the mines to a depth of 2 to 3 km consistent with previous studies. The magnitudes of these events ranged from less thanM _c 0 to 1.6. In addition to the unusual depths of these latter events, an anomalous aspect displayed by the events was an apparent dilatational focal mechanism suggesting a non-double-couple, possibly implosional source. Implosional events have been observed in other studies of mine seismicity; however, the generally inadequate instrumental coverage of the focal sphere has cast some doubt on the validity of such mechanisms. Previously suggested source mechanisms for such implosional events have included tensional failure through strata collapse, and a shear-implosional displacement mechanism. Shear failure must be involved in the failure process of the Gentry Mountain implosional events as evidenced by well-defined shear waves in the observed seismograms. Simultaneous monitoring in the East Mountain coal mining area to the south by the University of Utah revealed typical shear failure events mixed with implosional events. The observed double-couple, reverse focal mechanisms at East Mountain were similar to mechanisms determined in previous studies and a composite focal mechanism determined in this study for a sequence outside the mining areas. This suggested that the shear events within the mining areas are being influenced by the regional tectonic stress field. Thus in addition to the seismic events associated with caving of the roof from the longwall operation, there appear to be at least two other types of mining-induced seismic events occurring in the eastern Wasatch Plateau, both submine in origin: (1) events characterized by apparent non-double-couple possibly implosional focal mechanisms and well-defined shear waves; and (2) shear events, which are indistinguishable from tectonic earthquakes and may be considered mining triggered earthquakes. The small mining-induced stress changes that occur beyond a few hundred meters from the mine workings suggest both types of seismic events are occurring on critically stressed, pre-existing zones of weakness. Topography, overburden, method of mining, and mine configuration also appear to be significant factors influencing the occurrence of the implosional submine events.  相似文献   

Geostatistical Estimation of Hydraulic Head Gradients     

Ross D. Philip  Peter K. Kitanidis 《Ground water》1989,27(6):855-865

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31P solid-state nuclear magnetic resonance spectroscopy of aluminum phosphate minerals     

William F. Bleam  Philip E. Pfeffer  James S. Frye 《Physics and Chemistry of Minerals》1989,16(5):455-464

This study examines the links between ³¹P solidstate NMR studies of aluminum phosphate minerals and their crystallographic structures. We found that ³¹P isotropic chemical shift values, _iso, carry little information about mineral structures. There seems to be no relation between the chemical shift anisotropy, =₃₃–₁₁ (₃₃>₂₂> ₁₁), and indicies of phosphate-tetrahedra distortion. ³¹P¹H heteronuclear magnetic dipole interactions, on the other hand, carry important information about hydrous phosphate mineral structures, information that should prove to be quite valuable in studies of phosphate adsorbed on mineral surfaces. This interaction can be measured through a variety of qualitative and quantitative experiments. It appears that spin diffusion is so rapid that subtle differences in hydrogen-bonding environments cannot be resolved.  相似文献   

Generation of Hydrogen Gas as a Result of Drilling Within the Saturated Zone   总被引：1，自引：0，他引：1  

Bruce N. Bjornstad  James P. McKinley  Todd O. Stevens  Shirley A. Rawson  James K. Fredrickson  Philip E. Long 《Ground Water Monitoring & Remediation》1994,14(4):140-147

Hydrogen gas was discovered within the steel casing above standing water in a percussion-drilled borehole on the Hanlord Site in south-central Washington state. In situ measurements of the borehole fluids indicated anoxic, low-Eh (<-400 mV) conditions. Ground water sampled from adjacent wells in the same formation indicated that the ground water was oxygenated. H₂ was generated during percussion drilling, due to the decomposition of borehole waters as a result of aqueous reactions with drilled sediment and steel from the drilling tools or casing. The generation of H₂ within percussion-drilled boreholes that extend below the water table may be more common than previously realized. The ambient concentration of H₂ produced during drilling was limited by microbial activity within the casing-resident fluids. H₂ was generated abiotically in the laboratory, whereby sterilized borehole slurry samples produced 100 times more H₂ than unsterilizcd samples. It appears that H₂ is metabolized by microorganisms and concentrations might be significantly greater if not for microbial metabolism.  相似文献   

Historical changes in sediments of Pyramid Lake,Nevada, USA: consequences of changes in the water balance of a terminal desert lake   总被引：1，自引：0，他引：1  

Martin E. Lebo  John E. Reuter  Philip A. Meyers 《Journal of Paleolimnology》1994,12(2):87-101

Sediment cores from the shallow and deep basins of Pyramid Lake, Nevada, revealed variations in composition with depth reflecting changes in lake level, river inflow, and lake productivity. Recent sediments from the period of historical record indicate: (1) CaCO₃ and organic content of sediment in the shallow basin decrease at lower lake level, (2) CaCO₃ content of deep basin sediments increases when lake level decreases rapidly, and (3) the inorganic P content of sediments increases with decreasing lake volume. Variations in sediment composition also indicate several periods for which productivity in Pyramid Lake may have been elevated over the past 1000 years. Our data provide strong evidence for increased productivity during the first half of the 20th Century, although the typical pattern for cultural eutrophication was not observed. The organic content of sediments also suggests periods of increased productivity in the lake prior to the discovery and development of the region by white settlers. Indeed, a broad peak in organic fractions during the 1800's originates as an increase starting around 1600. However, periods of changing organic content of sediments also correspond to periods when inflow to the lake was probably at extremes (e.g. drought or flood) indicating that fluctuations in river inflow may be an important factor affecting sediment composition in Pyramid Lake.  相似文献   

PHYSICAL GEOGRAPHY IN SOUTHEAST ASIA: PAST THEMES, CURRENT STATUS AND FUTURE TRENDS     

Avijit Gupta  M.A.  Ph.D.  P.P. Wong  M.A.  Ph.D. 《Singapore journal of tropical geography》1994,14(2):252-264

Our knowledge regarding the physical geography of Southeast Asia is incomplete to a surprising extent. This paper reviews the past research, describes the ongoing work, and attempts to identify the future trends. Coverage of such a large area, even for the last 25 years, requires study of publications in several languages and coping with literature which is not easily available. Therefore certain topics. which are prominent in current research and likely to remain so in the future were chosen and reviewed in detail. Such topics include studies related to active plate margin features; the Pleistocene in Southeast Asia; erosion and sedimentation rates; rainforest; river systems; karst in Southeast Asia; coastal geomorphology; and the urban environment. Environmental studies are rapidly gaining importance chiefly because of (a) the destruction of the natural vegetation and the associated loss of biodiversity and (b) the growing problems due to accelerated erosion and sedimentation This trend is likely to continue with accelerated destruction of forests, development of coastal areas, and urbanization of the landscape The direction of research in physical geography of Southeast Asia has been determined by a combination of individual research interest, governmental priorities, and international expectations  相似文献