paragenetic and mineral chemical relationships in orthoamphibole bearing gneisses from enderby land east antarctica a record of proterozoic uplift abstract polymetamorphic orthoamphibole bearing gneisses from the vicinity of shear zones in casey bay enderby land antarctica record both the overprinting of archaean granulite lithologies by proterozoic metamorphism and the subsequent evolution of the latter episode during localized deformation mineral chemistry and zoning relationships in orthoamphibole garnet kyanite quartz and later orthoamphibole garnet cordierite quartz assemblages are used together with interpretation of reaction and corona textures to constrain the proterozoic pressure temperature path experienced by the rocks consideration of reaction topologies p t x fe mg a1 relationships in orthoamphibole bearing assemblages and standard geothermobarometry indicate that the gneisses underwent a near isothermal decompression p t history steep positive dp dt from 8 kbar and 700 c to 5 5kbar and 650 c this uplift path is correlated with the general effects of rayner complex metamorphism and deformation which occurred after 1100 ma in a major erogenic belt south of casey bay

varves of the dead sea sedimentary record abstract the sedimentary record of the dead sea provides an exceptional high resolution archive of past climate changes in the drought sensitive eastern mediterranean levant a key region for the development of humankind at the boundary of global climate belts moreover it is the only deep hypersaline lake known to have deposited long sequences of finely laminated annually deposited sediments i e varves of varied compositions including aragonite gypsum halite and clastic sediments vast efforts have been made over the years to decipher the environmental information stored in these evaporitic clastic sequences spanning from the pleistocene lake amora to the holocene dead sea a general characterisation of sediment facies has been derived from exposed sediment sections as well as from shallow and deep water sediment cores during high lake stands and episodes of positive water budget mostly during glacial times alternating aragonite and detritus laminae aad facies were accumulated whereas during low lake stands and droughts prevailing during interglacials laminated detritus ld facies and laminated halite lh facies dominate the sequence in this paper we i review the three types of laminated sediments of the dead sea sedimentary record aad ld and lh facies ii discuss their modes of formation deposition and accumulation and their interpretation as varves and iii illustrate how dead sea varves are utilized for palaeoclimate reconstructions and for establishing floating chronologies

on cyclonic tracks over the eastern mediterranean abstract in this study an updated and extended climatology of cyclonic tracks affecting the eastern mediterranean region is presented in order to better understand the mediterranean climate and its changes this climatology includes intermonthly variations classification of tracks according to their origin domain dynamic and kinematic characteristics and trend analysis the dataset used is the 1962 2001 2 5 2 5 40 yr european centre for medium range weather forecasts ecmwf re analysis era 40 the identification and tracking of the cyclones was performed with the aid of the melbourne university algorithm it was verified that considerable intermonthly variations of track density occur in the eastern mediterranean consistent with previous studies for the entire mediterranean while further interesting new features have been revealed the classification of the tracks according to their origin domain reveals that the vast majority originate within the examined area itself mainly in the cyprus

characterization of deep saline aquifers in the becancour area st lawrence lowlands quebec canada implications for co2 geological storage the present paper provides a case study of the assessment of the potential for co2 storage in the deep saline aquifers of the becancour region in southern quebec this assessment was based on a hydrogeological and petrophysical characterization using existing and newly acquired core and well log data from hydrocarbon exploration wells analyses of data obtained from different sources provide a good understanding of the reservoir hydrogeology and petrophysics profiles of formation pressure temperature density viscosity porosity permeability and net pay were established for lower paleozoic sedimentary aquifers lateral hydraulic continuity is dominant at the regional scale whereas vertical discontinuities are apparent for most physical and chemical properties the covey hill sandstone appears as the most suitable saline aquifer for co2 injection storage this unit is found at a depth of more than 1 km and has the following properties fluid pressures exceed 14 mpa temperature is above 35 c salinity is about 108 500 mg l matrix permeability is in the order of 3 10 16 m2 0 3 mdarcy with expected higher values of formation scale permeability due to the presence of natural fractures mean porosity is 6 net pay reaches 282 m available pore volume per surface area is 17 m3 m2 rock compressibility is 2 10 9 pa 1 and capillary displacement pressure of brine by co2 is about 0 4 mpa while the containment for co2 storage in the becancour saline aquifers can be ensured by appropriate reservoir characteristics the injectivity of co2 and the storage capacity could be limiting factors due to the overall low permeability of aquifers this characterization offers a solid basis for the subsequent development of a numerical hydrogeological model which will be used for co2 injection capacity estimation co2 injection scenarios and risk assessment

numerical studies of fluid leakage from a geologic disposal reservoir for co2 show self limiting feedback between fluid flow and heat transfer 1 leakage of co2 from a hypothetical geologic storage reservoir along an idealized fault zone has been simulated including transitions between supercritical liquid and gaseous co2 we find strong non isothermal effects due to boiling and joule thomson cooling of expanding co2 leakage fluxes are limited by limitations in conductive heat transfer to the fault zone the interplay between multiphase flow and heat transfer effects produces non monotonic leakage behavior

self healing of cement fractures under dynamic flow of co2 rich brine fractures and defects in wellbore cement can lead to increased possibilities of co2 leakage from abandoned wells during geological carbon sequestration to investigate the physicochemical response of defective wellbore cement to co2 rich brine we carried out a reactive flow through experiment using an artificially fractured cement sample at a length of 224 8 mm a brine solution with dissolved co2 at a ph of approximately 3 9 was injected through the sample at a constant rate of 0 0083 cm3 s surface optical profilometry analysis and 3 d x ray microtomography imaging confirmed fracture closure and self healing behavior consistent with the measured permeability decrease visual inspection of the reacted fracture surface showed the development of reactive patterns mapping the flow velocity field inside the fracture as well as restricted flow toward the sample outlet the postexperiment permeability of the core sample was measured at half of its initial permeability a reactive transport model was developed with parameters derived from the experiment to further examine property evolution of fractured cement under dynamic flow of co2 rich brine sensitivity analysis showed that residence time and the size of initial fracture aperture are the key factors controlling the tendency to self healing or fracture opening behavior and therefore determine the long term integrity of the wellbore cement longer residence time and small apertures promote mineral precipitation fracture closure and therefore flow restriction this work also suggests a narrow threshold separating the fracture opening and self sealing behavior

moisture source in the hyblean mountains region south eastern sicily italy evidence from stable isotopes signature abstract here the authors present results of an isotope study on precipitation collected during a 2 a period from a rain gauge network consisting of 6 stations located at different elevations in the hyblean mountains hm region in south eastern sicily the slope of the local meteoric water line d 6 50 18 o 9 87 obtained for the region suggests that precipitation is affected by evaporation during rainfall events the main variations in rainwater isotope composition are due to seasonal effects and elevation an average 2 h excess value of 21 2 was found for precipitation events less affected by evaporation i e when the rainfall was 65 mm month the spatial distribution of o isotope composition of precipitation shows a negative gradient from east and south to the inner areas the depositional rate of cl used as a tracer of the origin of air masses is highest at the coastal rain gauges sr and mrg stations and lowest on the northern flank of the hm region sc station based on these findings a model is proposed for the origin of precipitation in the hm region which assumes that a mediterranean derived component is the main source of moisture in the studied area d h and 18 o 16 o ratios of inferred meteoric recharge waters were also compared with the isotope composition of waters collected from the main local springs and wells the best linear fit of the 18 o vs d relationship for hyblean groundwater is d 4 85 18 o 2 01 the enrichment of heavy isotopes in hyblean groundwater is probably due to evaporation occurring after precipitation events or to a recharging contribution from surface waters lakes or rivers enriched in heavy isotopes

interaction between co2 rich sulfate solutions and carbonate reservoir rocks from atmospheric to supercritical co2 conditions experiments and modeling abstract a test site for co 2 geological storage is situated in hontomin burgos northern spain with a reservoir rock that is mainly composed of limestone during and after co 2 injection the resulting co 2 rich acid brine gives rise to the dissolution of carbonate minerals calcite and dolomite and gypsum or anhydrite at depth may precipitate since the reservoir brine contains sulfate experiments using columns filled with crushed limestone or dolostone were conducted under different p p co 2 conditions atmospheric 1 10 3 5 bar subcritical 10 10 bar and supercritical 150 34 bar t 25 40 and 60 c and input solution compositions gypsum undersaturated and gypsum equilibrated solutions we evaluated the effect of these parameters on the coupled reactions of calcite dolomite dissolution and gypsum anhydrite precipitation the crunchflow and phreeqc v 3 numerical codes were used to perform reactive transport simulations of the experiments within the range of p p co 2 and t of this study only gypsum precipitation took place no anhydrite was detected and this only occurred when the injected solution was equilibrated with gypsum under the p p co 2 t conditions the volume of precipitated gypsum was smaller than the volume of dissolved carbonate minerals yielding an increase in porosity up to 4 a decrease in t favored limestone dissolution regardless of p co 2 owing to increasing undersaturation with decreasing temperature however gypsum precipitation was favored at high t and under atmospheric p co 2 conditions but not at high t and under 10 bar of p co 2 conditions the increase in limestone dissolution with p co 2 was directly attributed to ph which was more acidic at higher p co 2 limestone dissolution induced late gypsum precipitation long induction time in contrast to dolostone dissolution which promoted rapid gypsum precipitation moreover owing to the slow kinetics of dolomite dissolution with respect to that of calcite both the volume of dissolved mineral and the increase in porosity were larger in the limestone experiments than in the dolostone ones under all p co 2 conditions 10 3 5 and 10 bar by increasing p co 2 carbonate dissolution occurred along the column whereas it was localized in the very inlet under atmospheric conditions this was due to the buffer capacity of the carbonic acid which maintains ph at around 5 and keeps the solution undersaturated with respect to calcite and dolomite along the column 1d reactive transport simulations reproduced the experimental data carbonate dissolution and gypsum precipitation for different p p co 2 t conditions drawing on reaction rate laws in the literature we used the reactive surface area to fit the models to the experimental data the values of the reactive surface area were much smaller than those calculated from the geometric areas

monitoring and volumetric estimation of injected co2 using 4d seismic petrophysical data core measurements and well logging a case study at ketzin germany more than 50 000 tons of co2 have been injected at ketzin into the stuttgart formation a saline aquifer at approximately 620 m depth as of summer 2011 we present here results from the 1 st repeat 3d seismic survey that was performed at the site in autumn 2009 after about 22 000 tons of co2 had been injected we show here that rather complex time lapse signatures of this co2 can be clearly observed within a radius of about 300 m from the injection well the highly irregular amplitude response within this radius is attributed to the heterogeneity of the injection reservoir time delays to a reflection below the injection level are also observed petrophysical measurements on core samples and geophysical logging of co2 saturation levels allow an estimate of the total amount of co2 visible in the seismic data to be made these estimates are somewhat lower than the actual amount of co2 injected at the time of the survey and they are dependent upon the choice of a number of parameters in spite of some uncertainty the close agreement between the amount injected and the amount observed is encouraging for quantitative monitoring of a co2 storage site using seismic methods

crustal evolution in south india constraints from nd isotopes nd isotope analyses from a range of lithologies including charnockites metasediments and granitoids that comprise the high grade terrain of south india define contrasting age provinces north of the palghat cauvery shear zone the karnataka craton and the granulite blocks of nilgiri and madras are characterized by model nd ages from 3 4 to 2 4 ga with significant crustal growth during the late archean south of the palghat cauvery shear zone a pan african granulite facies event resulted in sm nd fractionation as observed in several incipient charnockite localities model nd age calculations that allow for sm nd fractionation at 550 ma yield ages in the range of 2 9 to 1 3 ga this range compares closely with published model nd ages from the high grade terrain of sri lanka mid proterozoic crustal growth 1 1 ga observed in the vijayan complex of sri lanka may have provided source material for metasediments characterized by young model nd ages in southern peninsular india the palghat cauvery shear z

experimental evaluation of mixed fluid reactions between supercritical carbon dioxide and nacl brine relevance to the integrity of a geologic carbon repository abstract the reactive behavior of a mixed fluid supercritical co2 and brine under physical chemical conditions relevant to geologic storage and sequestration in a carbon repository is largely unknown experiments were conducted in a flexible cell hydrothermal apparatus to evaluate fluid rock aquifer plus aquitard reactions that may adversely impact the integrity of the repository a 5 5 molal nacl brine rock system was held at 200 c and 200 bars 20 mpa for 32 days 772 h to approach steady state then injected with co2 and allowed to react for an additional 45 days 1079 h in a separate experiment at 200 c and 200 bars the system was allowed to react for 77 days 1845 h without injection of co2 corroded magnesite and euhedral siderite crystallized in a paragenetic sequence after co2 injection nucleation and growth of siderite on shale suggests the aquitard is a reactive component in the system changes in elemental abundances in the brine following addition of co2 include ph decrease and depletion of sodium due to accelerated growth of analcime a ph increase follows pressure and temperature decrease and loss of saturated co2 from acidic brine silica concentrations and dissolution rates are enhanced and silica precipitation inhibited in the acidic brine geochemical reactions in a carbon repository extend beyond ph decrease and carbonate mineral precipitation rock dominated reaction systems yield to acid dominated and related reactions controlled by mixed fluid equilibria i e a fluid dominated system escape of co2 or migration of brine from the repository into overlying aquifers may cause silica super saturation and increased alkalinity due to mixed fluid phase equilibria these geochemical changes could be monitored in aquifers as indicators of repository integrity return of silica super saturated brine to a rock dominated reaction system buffered to neutral ph conditions may enhance precipitation of quartz chalcedony or amorphous silica in addition to the potential effects beneficial or deleterious that silica super saturation and precipitation may hold for repository performance an understanding of the effects of multi phase equilibrium relationships between supercritical co2 and dissolved silica in aquifer brine systems also raises new questions for a variety of geologic systems multi phase fluid equilibria may for example account for quartz cements in some sedimentary basin sandstones and quartz vein mineralization in some ore districts

dolomite dissolution kinetics in aqueous solutions in the presence of organic and inorganic additives at 25 c and pco 2 1 atm abstract the steady state dissolution rate of dolomite was studied at 25 c and 1 atm co2 total pressure in deionised water in the absence control and presence of twenty seven different organic and inorganic additives at low concentration 1 mm these additives are most likely present at low concentrations

dawsonite and ankerite formation in the ldx 1 structure yinggehai basin south china sea an analogy for carbon mineralization in subsurface sandstone aquifers abstract the geochemistry and petrology of the ldx 1 structure of the yinggehai basin a natural analog of a sedimentary carbon storage site was investigated to understand the consequences of the charging of co2 gas in this system the rocks in this structure are dominated by subarkose and sublitharenite sandstones the authigenic minerals formed after co2 injection are dawsonite microcrystalline quartz kaolinite and ankerite dawsonite and ankerite are formed just beneath a co2 bearing anticlinal structure due to the reactions between silicate minerals feldspars and clay minerals and the fluid phase carbon and oxygen isotopic analyses indicate that the main carbon source for dawsonite and ankerite formation was mantle magmatic co2 the aqueous activities of sodium and calcium the partial pressure of co2 ph and temperature are the key factors influencing the stability of the dawsonite and ankerite the presence of the anticlinal structure maintaining a locally high co2 partial pressure in the waters beneath this structure is likely responsible for the observed long term persistence of dawsonite and ankerite in this system

sapphirine and corundum bearing granulites from karur madurai block southern india we report new occurrences of sapphirine and corundum bearing granulites intercalated within orthogneisses at lachmanapatti and malappatty in the northern part of madurai block sapphirine in these localities occurs either as needle like intergrowth with cordierite and corundum in symplectites and medium to fine grained euhderal to subhedral crystals associated with cordierite and corundum lachmanapatti or in association with plagioclase corundum and gedrite malappatty the sapphirine from lachmanapatti is highly magnesian xmg 0 87 0 94 with higher cr content up to 0 9 pfu as compared with those in other localities in the madurai block the sapphirine corundum association reported in this study has important bearing on the ultrahigh temperature metamorphism and exhumation history of the northern madurai block as well as on the tectonic evolution of the continental deep crust in southern india

convolutional time lapse seismic modeling for co2 sequestration at the dickman oilfield ness county kansas abstracttime lapse seismic modeling is routinely used to detect the state of hydrocarbon reservoirs at periodic time intervals the dickman field located in the u s midcontinent provides two possible co2 sequestration targets a regional deep saline reservoir is the primary objective and a shallower mature depleted oil reservoir is a secondary objective the goal of this work is to characterize and simulate monitoring of the co2 movement before during and after its injection into these sequestration targets including fluid flow paths reservoir property changes co2 containment and postinjection stability seismic images before during and after injection would improve understanding of the carbonate sequestration process and management our seismic simulation for time lapse co2 monitoring was based on flow simulator output over a 250 year injection and simulation period the seismic response was accomplished via convolutional 1d forward modeling this work will provide an evaluation for the ef

appraisal of global co2 storage opportunities using the geomechanical facies approach different tectonic settings exert different depositional process controls within the tectonic basin which influence co2 storage site suitability in terms of basin architecture caprock architecture reservoir quality stress state mechanical characteristics fractures burial depth geothermal gradient risk of orogenic modification structural stability and preservation potential we apply the concept of geomechanical facies where deposits are grouped together on the basis of engineering parameters that fulfil a specific role within the storage system e g reservoir caprock overburden to provide an assessment of co2 storage suitability for seven different tectonic settings the geomechanical facies data were analysed using two different multiple attribute decision analysis methodologies and the results show that foreland basins are likely to be the most suitable for co2 storage followed by passive continental margins terrestrial rift basins strike slip basins back arc basins with oceanic basins forearc basins and trench basins expected to be the least suitable the geomechanical facies approach was compared with two current storage projects sleipner and in salah and a natural co2 storage analogue miller to build confidence in the methodology finally the global distribution of the most likely co2 storage basins based on their geomechanical facies was mapped and correlated with co2 emission sources

screening and ranking of sedimentary basins for sequestration of co2 in geological media in response to climate change sedimentary basins are suitable to different degrees for co2 geological sequestration as a result of various intrinsic and extrinsic characteristics of which the geothermal regime is one of the most important warm basins are less favorable for co2 sequestration than cold basins because of reduced capacity in terms of co2 mass and because of higher co2 buoyancy which drives the upward co2 migration a set of 15 criteria with several classes each has been developed for the assessment and ranking of sedimentary basins in terms of their suitability for co2 sequestration using a parametric normalization procedure a basin s individual scores are summed to a total score using weights that express the relative importance of different criteria the total score is ranked to determine the most suitable basin or region thereof for the geological sequestration of co2 the method is extremely flexible in that it allows changes in the functions that express the importance of various classes for any given criterion and in the weights that express the relative importance of various criteria examples of application are given for canada s case and for the alberta basin in canada

ultra high temperature metamorphism and multistage decompressional evolution of sapphirine granulites from the palni hill ranges southern india sapphirine granulites from a new locality in the palni hill ranges southern india occur in a small enclave of migmatitic highly magnesian metapelites mg 85 72 within massive enderbitic orthogneiss they show a variety of multiphase reaction textures that partially overprint a coarse grained high pressure assemblage of bt opx ky grt pl qtz the sequence of reactions as deduced from the corona and symplectite assemblages together with petrogenetic grid considerations records a clockwise p t evolution with four distinct stages 1 equilibration of the initial high p assemblage in deep overthickened crust 12 kbar 800 900 c was followed by a stage of near isobaric heating presumably as a consequence of input of extra heat provided by the voluminous enderbitic intrusives during heating kyanite was converted to sillimanite and biotite was involved in a series of vapour phase absent melting reactions which resulted in the ultra high temperature assemblage opx crd kfs spr sil grt qtz bt coexisting with melt equilibration at c 950 1000 c 11 10 kbar 2 subsequently as a result of decompression of the order of 4 kbar at ultra high temperature a sequence of symplectite assemblages opx sil spr spr crdopx spr crdopx crdopx crd spl crd spl developed at the expense of garnet orthopyroxene and sillimanite this stage of near isothermal decompression implies rapid ascent of the granulites into mid crustal levels possibly due to extensional collapse and erosion of the overthickened crust 3 development of late biotite through back reaction of melt with residual garnet indicates a stage of near isobaric cooling to c 875 c at 7 8 kbar i e relaxation of the rapidly ascended crust to the stable geotherm 4 a second period of near isothermal exhumation up to c 6 5 kbar 850 c is indicated by the partial breakdown of late biotite through volatile phase absent melting reactions available isotope data suggest that the early part of the evolutionary history stages 1 3 is presumably coeval with the early proterozoic metamorphism in the extended granulite terrane of the nilgiri biligirirangan and shevaroy hills to the north while the exhumation of the granulites from mid crustal levels stage 4 occurred only during the pan african thermotectonic event which led to the accretion of the kerala khondalite belt to the south

non isothermal modeling of co2 injection into saline aquifers at a low temperature to investigate the effects of temperature on the co2 storage in the deep saline aquifers we set up a 2 d non isothermal numerical model with simulating the co2 injection into the aquifers at a low temperature the evolution of the co2 plume and the temperature in the aquifer were studied and using temperature signal to monitor the arrival of co2 plume was also evaluated in addition the deviance of the isothermal model was analyzed the results show when the cold co2 is injected into the aquifers the aquifer can be divided into three zones in the direction away from the injection well during the injection period temperature drop zone temperature transition zone and temperature rise zone the temperature rise can reach approximately 1 c in the temperature rise zone during the injection period which should be enough for the temperature sensor to detect the arrival of the co2 plume however the value of the temperature rise reduces with distance from the injection well consequently we indicate that it is not suitable to monitor the long term migration of the co2 plume using temperature signal especially after the injection stops the initial formation temperature strongly affects the evolution of the co2 plume and the temperature distribution after the co2 injection not only the storage is safer but also using temperature signal to monitor co2 plume is more feasible in the cold aquifer the deviance of the isothermal model is small in the mass fraction of dissolved co2 and the arrival time of co2 plume throughout the simulation however the deviance of pressure buildup is great and increases with time up to 15 during the injection period the non isothermal model is necessary to accurately assess the pressure buildup around the injection well during the co2 injection period

basin delineation with a 40 hour passive seismic record several geophysical methods exist to delineate the lower interface of a sedimentary basin most popularly employed are gravity and magnetic surveys and surface wave inversion while all three methods are successful overall in estimating an average basin depth they fail to find a more detailed depth variation as an alter native we consider three passive seismic techniques using especially body waves we analyze 40 hours of data recorded with 110 stations installed over the abu gharadig basin in egypt in an earlier study we found the frequency band of 0 09 1 0 hz to be dominated by body waves as a first method we apply body wave seismic interfero metry si using body wave noise we extract pp and ss reflections from the basin floor we estimate the depth of the basin to be around 4 8 km as a second technique we estimate the resonance spectra of the basin using the horizontal to vertical h v spectral ratio using surface wave noise we find an extremum that is probably related to the complete sedimentary package using this peak we find a basin depth of 5 4 km using s phase arrivals we find two extrema in the h v which are probably related to the s wave resonances of two distinct layers in the basin as a third method we compute receiver functions rfs based on the rfs we can confirm the presence of a large interface in the upper crust but we cannot well constrain its depth

al zoning in orthopyroxene in a sapphirine quartzite evidence for 1120 c uht metamorphism in the napier complex antarctica and implications for the entropy of sapphirine a unique sapphirine orthopyroxene quartz granulite from mt riiser larsen in the tula mountains of enderby land east antarctica preserves two generations of coarse and texturally equilibrated orthopyroxene and sapphirine coexisting with quartz initial subhedral orthopyroxene porphyroblasts retain core compositions enriched in al2o3 12 2 0 5 wt compared with their rims and finer orthopyroxene 9 6 0 5 wt al2o3 that forms granoblastic textures with sapphirine sapphirine and quartz also form symplectites on and along cleavage planes within orthopyroxene these compositional and textural features are consistent with the reaction 2mgal2sio6 mg2al4 sio10 sio2 leading to the formation of sapphirine quartz at the expense of aluminous orthopyroxene calculations in the mas and fmas systems and theoretical considerations involving the phases enstatite sapphirine sillimanite quartz and cordierite indicate that the reaction above progresses from left to right with decreasing temperature in the orthopyroxene sapphirine quartz field at pressures of ca 8 10 kbar the temperature difference required to account for the ca 2 5 3 wt decrease in al2o3 in orthopyroxene is at least 60 80 c and implies peak temperatures for the initial assemblage of at least 1120 c if the second granoblastic assemblage equilibrated at 1040 c the p t conditions required by the sapphirine quartz association and other p t sensitive assemblage indicators in the napier complex it is not possible to distinguish whether the two assemblages are simply related by cooling and re equilibration or reflect a polyphase evolution involving the superposition of a second uht event on an earlier even higher temperature uht metamorphism preliminary thermodynamic modelling of the reaction above incorporating the observed range in orthopyroxene al2o3 zoning indicates that present estimates for the entropy of high temperature sapphirine are potentially too high by 15 18 compared with sapphirine entropy estimates that are consistent with mas system experiments the mt riiser larsen sapphirine quartz rocks preserve the first definitive record of regional metamorphic temperatures in excess of 1120 c in the napier complex or indeed any uht granulite terrain worldwide similarly high peak temperatures may be retrieved from detailed studies of sapphirine quartz granulites from other regions further expanding the thermal realm of crustal metamorphism but progress will critically depend on the experimental acquisition of new entropy data for sapphirine

hydrogeochemical and isotopic evidence for trans formational flow in a sedimentary basin implications for co2 storage deep saline aquifers are considered as the most promising option for geologic disposal of co2 one of the main concerns however is the integrity of the caprocks between and above the storage formations here a hydrogeochemical and isotopic investigation is presented using ionic chemistry stable isotopes 18o 2h and 87sr 86sr and radiocarbon dating on five saline aquifers on a regional scale namely neogene minghuazhen guantao ordivician cambrian and precambrian all found in the bohai bay basin bbb in north china groundwater recharge flow pattern age and mixing processes in the saline aquifers show that the neogene guantao formation ng in the jizhong and huanghua depressions on both of the west and east sides of the cangxian uplift is a prospective reservoir for co2 sequestration with a well confined regional seal above which is the clayey layers in the neogene minghuazhen formation nm however this is not the case in the cangxian uplift where the ng is missing where structural high and fault zones are developed creating strong hydraulic connections and trans formational flow to the nm aquifer comparing storage capacity and long term security between the various hydrogeologic units the depressions are better candidate sites for co2 sequestration in the bbb

a preliminary site selection system for a co2 ages project and its application in china because of the high costs involved in co2 sequestration in deep saline formations it has been difficult for its widespread application in the short term recently however a new technology called combined geothermal production co2 sequestration technology has made the technique more attractive not only by increasing the co2 storage capacity but also by decreasing the operational costs through the utilization of geothermal energy either directly or for the purpose of producing electricity a co2 aided or co2 involved geothermal extraction system co2 ages is presented based on existing technologies and the new ideas of combined geothermal production co2 sequestration introduced in this paper this system can be used to extract geothermal energy from sedimentary aquifer formations low medium temperature at different stages the purpose of this paper is to set up an evaluation system for selecting a suitable site for this co2 ages system there are both similarities and differences in the procedure needed for selecting a site for a conventional pure co2 sequestration and for this co2 ages system both are carried out at different scales including basin region and target formation scales the biggest difference is the temperature gradient which plays an opposite role in the two systems by using the preliminary ranking and screening method presented in this paper it can be shown that the bohaiwan songliao and qiangtang basins have the highest potential for the application of this co2 ages technology however if co2 sequestration is considered alone the ordos tarim and bohaiwan basins should be selected as the best three operational sites in china while preliminary evaluation methods can provide some useful information on the selection of the best sites for the combined geothermal production co2 sequestration technology more detailed work is still required because of the strong uncertainties that exist in the determination of the upper and lower boundaries for each indicator

are changes in time lapse seismic data due to fluid substitution or rock dissolution a co2 sequestration feasibility study at the pohokura field new zealand seismic methods are commonly used to monitor the subsurface when carbon dioxide co2 is injected into a reservoir besides fluid saturation and pressure changes co2 water mixtures may cause rock alteration in this petrophysical study we compare the elastic property changes due to fluid replacement and those due to mineral dissolution for carbonate cemented sandstones at the pohokura field new zealand we quantify the effects of fluid substitution from fully brine to fully supercritical co2 saturation and carbonate cement dissolution on the seismic signatures of the reservoir rocks by combining laboratory results petrographic analyses and geophysical well log data we conclude that elastic property changes due to mineral dissolution are significantly greater than those due to fluid substitution alone the northern part of the pohokura field has coarser grained sandstones which experience the largest changes in wave speeds our hypothesis is that these changes result from carbonate cement dissolution in the presence of co2 water sandstone reactions if time lapse seismic data were to be acquired in this field the northern area could show p wave velocity reductions of up to 20 and a 131 7 increase in seismic amplitude from a brine saturated rock to an altered fully co2 saturated rock in comparison the southern part of the field where sandstones are mostly fine grained we expect a p wave velocity decrease of 6 if such dissolution process took place finally we show that the elastic properties of the reservoir rocks can be described with the constant cement model the model is used to predict that the dissolution process reduces the volume of grain contact cement on average from 2 5 to 1 75 of the total rock mineral volume our analysis suggests that changes to the rock frame which includes carbonate minerals cannot be ignored for a co2 injection scenario

flow through experiments on water rock interactions in a sandstone caused by co2 injection at pressures and temperatures mimicking reservoir conditions abstract flow through experiments were performed in a newly designed experimental setup to study the water rock interactions caused by co 2 injection in sandstones obtained from the altmark natural gas reservoir under the simulated reservoir conditions of 125 c and 50 bar co 2 partial pressure two different sets of experiments were conducted using co 2 saturated millipore water and co 2 saturated brine 41 62 g l 1 nacl and 31 98 g l 1 cacl 2 2h 2 o mimicking the chemical composition of the reservoir formation water the major components in the sandstone were quartz clasts cement feldspars clay minerals illite and chlorite and cements of carbonates and anhydrite fluid analysis suggested the predominant dissolution of anhydrite causing increased concentrations of calcium and sulfate at early time periods at non equilibrium geochemical conditions the ca so 4 molar ratio 1 indicated the concurrent dissolution of both calcite and anhydrite dissolution of feldspar and minor amounts of clay chlorite was also evident during the flow through experiments the permeability of the sample increased by a factor of two mostly due to the dissolution of rock cements during brine injection geochemical modeling suggests calcite dissolution as the major buffering process in the system the results may in future studies be used for numerical simulations predicting co 2 storage during injection in sandstone reservoirs

regional search selection and geological characterization of a large anticlinal structure as a candidate site for co2 storage in northern germany this paper reports on the regional screening selection and geological characterisation of a potential on shore co2 storage site saline aquifer in north eastern germany the main objective of this study was to identify and investigate a candidate storage site capable to accommodate the total amount of approximately 400 million tons of co2 such a volume is produced by a modern lignite fired power plant within its operation lifetime of approximately 40 years within north eastern germany several saline aquifers of triassic jurassic and cretaceous age have been evaluated with respect to their regional occurrence storage potential and basic reservoir properties subsequent to a ranking considering different criteria the anticlinal structure schweinrich holding suitable saline aquifers of the uppermost triassic and lowest jurassic has been selected from a number of identified candidate sites according to results of the geological site characterisation including structural geological investigations and 3d reservoir modelling the structure schweinrich seems to be a suitable site for industrial large scale co2 storage further data acquisition new wells and 3d seismics and research more detailed and comprehensive modelling is needed in order to prove the structural integrity of the storage site and assure long term safety 2007 springer verlag

first report of sapphirine bearing rocks from the palghat cauvery shear zone system southern india abstract silica deficient mg al granulites from paramati within the palghat cauvery shear system contain sapphirine in association with corundum spinel and sillimanite gedrite which occurs commonly in this locality coexists with cordierite corundum and sillimanite mineral assemblages and reaction textures indicate peak metamorphism at ultrahigh temperature conditions this new locality provides evidence for extreme crustal metamorphism along the archean proterozoic collision boundary in southern india

effects of in situ conditions on relative permeability characteristics of co2 brine systems carbon dioxide capture and geological storage ccgs is an emerging technology that is increasingly being considered for reducing greenhouse gas emissions to the atmosphere deep saline aquifers provide a very large capacity for co2 storage and unlike hydrocarbon reservoirs and coal beds are immediately accessible and are found in all sedimentary basins proper understanding of the displacement character of co2 brine systems at in situ conditions is essential in ascertaining co2 injectivity migration and trapping in the pore space as a residual gas or supercritical fluid and in assessing the suitability and safety of prospective co2 storage sites because of lack of published data the authors conducted a program of measuring the relative permeability and other displacement characteristics of co2 brine systems for sandstone carbonate and shale formations in central alberta in western canada the tested formations are representative of the in situ characteristics of deep saline aquifers in compacted on shore north american sedimentary basins the results show that the capillary pressure interfacial tension relative permeability and other displacements characteristics of co2 brine systems depend on the in situ conditions of pressure temperature and water salinity and on the pore size distribution of the sedimentary rock this paper presents a synthesis and interpretation of the results

first evidence of ultrahigh temperature decompression from the granulite province of southern india sapphirine bearing orthopyroxene sillimanite garnet granulites of the palni hill ranges record evidence of ultrahigh temperature metamorphism during which primary mineral assemblages were partially overprinted by a succession of reaction coronas and symplectites that together suggest decompression model system petrogenetic grids allow constraints to be placed on the evolution of p t conditions as recorded by reaction relationships of successively developed mineral assemblages thermobarometry on garnet bearing assemblages allows minimum constraints to be placed on p t conditions for the primary mineral assemblages primary mineral assemblages suggest p t conditions of c 12 kbar and c 900 1000 c secondary mineral assemblages in reaction textures show a two stage decompression to probable p t conditions of c 5 kbar and c 850 c the inferred p t path is clockwise

chemical changes in fluid composition due to co2 injection in the altmark gas field preliminary results from batch experiments dissolution precipitation phenomena induced by co2 injection to altmark permian sandstone were observed through laboratory experiments carried out under simulated reservoir conditions 125 c and 50 bars of pressure the rock sample was collected from the altmark gas reservoir which is being considered for enhanced gas recovery two sets of experiments were performed with pulverized rock samples in a closed batch reactor with either pure water run 1 or 3 m aqueous nacl solution run 2 and reacted with injected co2 for 3 5 and 9 days the liquid samples were analyzed by inductively coupled plasma optical emission spectroscopy and total reflection x ray fluorescence where the latter proved to be a feasible alternative to conventional analytical techniques especially since only small sample volumes about 10 l are needed chemical analysis for both fluids water and nacl brine indicated a significant dissolution of calcite and anhydrite in the solution which might be a crucial process during co2 injection the brine solution enhanced the dissolution of calcite and anhydrite compared to pure water at the beginning of the reaction moreover the progressive higher si4 al3 molar ratios in average by a factor of 3 in the brine experiments indicated quartz dissolution thermodynamic calculations of mineral saturation indices highlighted the dissolution of the ca bearing minerals which was in agreement with experimental results modeling enabled an evaluation of the dissolution processes of minerals in a low salinity region yet hindrances to model more saline conditions emphasize the need for further laboratory studies in order to parameterize models for deep aquifer conditions

geochemical monitoring for potential environmental impacts of geologic sequestration of co2 carbon dioxide sequestration is now considered an important component of the portfolio of options for reducing greenhouse gas emissions to stabilize their atmospheric levels at values that would limit global temperature increases to the target of 2 c by the end of the century pacala and socolow 2004 ipcc 2005 2007 benson and cook 2005 benson and cole 2008 iea 2012 romanak et al 2013 increased anthropogenic emissions of co2 have raised its atmospheric concentrations from about 280 ppmv during pre industrial times to 400 ppmv today and based on several defined scenarios co2 concentrations are projected to increase to values as high as 1100 ppmv by 2100 white et al 2003 ipcc 2005 2007 eia 2012 global ccs institute 2012 an atmospheric co2 concentration of 450 ppmv is generally the accepted level that is needed to limit global temperature increases to the target of 2 c by the end of the century this temperature limit likely would moderate the adverse effects related to climate change that could include sea level rise from the melting of alpine glaciers and continental ice sheets and from the ocean warming increased frequency and intensity of wildfires floods droughts and tropical storms and changes in the amount timing and distribution of rain snow and runoff ipcc 2007 sundquist et al 2009 iea 2012 rising atmospheric co2 concentrations are also increasing the amount of co2 dissolved in ocean water lowering its ph from 8 1 to 8 0 with potentially disruptive effects on coral reefs plankton and marine ecosystems adams and caldeira 2008 schrag 2009 sundquist et al 2009 sedimentary basins in general and deep saline aquifers in particular are being investigated as possible repositories for the large volumes of

heat and mass transport during a groundwater replenishment trial in a highly heterogeneous aquifer changes in subsurface temperature distribution resulting from the injection of fluids into aquifers may impact physiochemical and microbial processes as well as basin resource management strategies we have completed a 2 year field trial in a hydrogeologically and geochemically heterogeneous aquifer below perth western australia in which highly treated wastewater was injected for large scale groundwater replenishment during the trial chloride and temperature data were collected from conventional monitoring wells and by time lapse temperature logging we used a joint inversion of these solute tracer and temperature data to parameterize a numerical flow and multispecies transport model and to analyze the solute and heat propagation characteristics that prevailed during the trial the simulation results illustrate that while solute transport is largely confined to the most permeable lithological units heat transport was also affected by heat exchange with lithological units that have a much lower hydraulic conductivity heat transfer by heat conduction was found to significantly influence the complex temporal and spatial temperature distribution especially with growing radial distance and in aquifer sequences with a heterogeneous hydraulic conductivity distribution we attempted to estimate spatially varying thermal transport parameters during the data inversion to illustrate the anticipated correlations of these parameters with lithological heterogeneities but estimates could not be uniquely determined on the basis of the collected data

effect of oxygen co injected with carbon dioxide on gothic shale caprock co2 brine interaction during geologic carbon sequestration abstract co injection of oxygen a significant component in co 2 streams produced by the oxyfuel combustion process can cause a significant alteration of the redox state in deep geologic formations during geologic carbon sequestration the potential impact of co injected oxygen on the interaction between synthetic co 2 brine 0 1 m nacl and shale caprock gothic shale from the aneth unit in utah and mobilization of trace metals was investigated at 10 mpa and 75 c a range of relative volume percentages of o 2 to co 2 0 1 4 and 8 were used in these experiments to address the effect of oxygen on shale co 2 brine interaction under various conditions major mineral phases in gothic shale are quartz calcite dolomite montmorillonite and pyrite during gothic shale co 2 brine interaction in the presence of oxygen pyrite oxidation occurred extensively and caused enhanced dissolution of calcite and dolomite pyrite oxidation and calcite dissolution subsequently resulted in the precipitation of fe iii oxides and gypsum caso 4 2h 2 o in the presence of oxygen dissolved mn and ni were elevated because of oxidative dissolution of pyrite the mobility of dissolved ba was controlled by barite baso 4 precipitation in the presence of oxygen dissolved u in the experimental brines increased to 8 14 g l with concentrations being slightly higher in the absence of oxygen than in the presence of oxygen experimental and modeling results indicate the interaction between shale caprock and oxygen co injected with co 2 during geologic carbon sequestration can exert significant impacts on brine ph solubility of carbonate minerals stability of sulfide minerals and mobility of trace metals the major impact of oxygen is most likely to occur in the zone near co 2 injection wells where impurity gases can accumulate oxygen in co 2 brine migrating away from the injection well will be continually consumed through the reactions with sulfide minerals in deep geologic formations

spatial characterization of the location of potentially leaky wells penetrating a deep saline aquifer in a mature sedimentary basin this work was motivated by considerations of potential leakage pathways for co2 injected into deep geological formations for the purpose of carbon sequestration because existing wells represent a potentially important leakage pathway a spatial analysis of wells that penetrate a deep aquifer in the alberta basin was performed and various statistical measures to quantify the spatial distribution of these wells were presented the data indicate spatial clustering of wells due to oil and gas production activities the data also indicate that the number of wells that could be impacted by co2 injection as defined by the spread of an injected co2 plume varies from several hundred in high well density areas to about 20 in low density areas these results may be applied to other mature continental sedimentary basins in north america and elsewhere where detailed information on well location and status may not be available

potential environmental issues of co2 storage in deep saline aquifers geochemical results from the frio i brine pilot test texas usa abstract sedimentary basins in general and deep saline aquifers in particular are being investigated as possible repositories for large volumes of anthropogenic co2 that must be sequestered to mitigate global warming and related climate changes to investigate the potential for the long term storage of co2 in such aquifers 1600 t of co2 were injected at 1500 m depth into a 24 m thick c sandstone unit of the frio formation a regional aquifer in the us gulf coast fluid samples obtained before co2 injection from the injection well and an observation well 30 m updip showed a na ca cl type brine with 93 000 mg l tds at saturation with ch4 at reservoir conditions gas analyses showed that ch4 comprised 95 of dissolved gas but co2 was low at 0 3 following co2 breakthrough 51 h after injection samples showed sharp drops in ph 6 5 5 7 pronounced increases in alkalinity 100 3000 mg l as hco3 and in fe 30 1100 mg l a slug of very high doc values and significant shifts in the isotopic compositions of h2o dic and ch4 these data coupled with geochemical modeling indicate corrosion of pipe and well casing as well as rapid dissolution of minerals especially calcite and iron oxyhydroxides both caused by lowered ph initially 3 0 at subsurface conditions of the brine in contact with supercritical co2 these geochemical parameters together with perfluorocarbon tracer gases pfts were used to monitor migration of the injected co2 into the overlying frio b composed of a 4 m thick sandstone and separated from the c by 15 m of shale and siltstone beds results obtained from the frio b 6 months after injection gave chemical and isotopic markers that show significant co2 2 9 compared with 0 3 co2 in dissolved gas migration into the b sandstone results of samples collected 15 months after injection however are ambiguous and can be interpreted to show no additional injected co2 in the b sandstone the presence of injected co2 may indicate migration from c to b through the intervening beds or more likely a short term leakage through the remedial cement around the casing of a 50 year old well results obtained to date from four shallow monitoring groundwater wells show no brine or co2 leakage through the anahuac formation the regional cap rock

gas buildup in lake nyos cameroon the recharge process and its consequences the gases dissolved in lake nyos cameroon were quantified recently december 1989 and september 1990 by two independent techniques in situ measurements using a newly designed probe and laboratory analyses of samples collected in pre evacuated stainless steel cylinders the highest concentrations of co2 and ch4 were 0 30 mol kg and 1 7 mmol kg respectively measured in cylinders collected 1 m above lake bottom probe measurements of in situ gas pressure at three different stations showed that horizontal variations in total dissolved gas were negligible total dissolved gas pressure near the lake bottom is 1 06 mpa 10 5 atm 50 as high as the hydrostatic pressure of 2 1 mpa 21 atm comparing the co2 profile constructed from the 1990 data to one obtained in may 1987 shows that co2 concentrations have increased at depths to below 150 m based on these profiles the average rate of co2 input to bottom waters was 2 6 108 mol a increased deep water temperatures require an average heat flow of 0 32 mw into the hypolimnion over the same time period the transport rates of co2 heat and major ions into the hypolimnion suggest that a low temperature reservoir of free co2 exists a short distance below lake bottom and that convective cycling of lake water through the sediments is involved in transporting the co2 into the lake from the underlying diatreme increased ch4 concentrations at all depths below the oxycline and a high14c content 41 modern in the ch4 4 m above lake bottom show that much of the ch4 is biologically produced within the lake the ch4 production rate may vary with time but if the co2 recharge rate remains constant co2 saturation of the entire hypolimnion below 50 m depth would require 140a given present day concentrations

intermonthly variability of cyclone tracks in the mediterranean abstract objective calculated monthly cyclonic tracks in the mediterranean are presented the intermonthly variations within each season are shown to be quite significant and an particularly notable for december january april may and june july we suggest that composite seasonal pictures are not faithful representations of the cyclonic routes over a complex terrain region like the mediterranean

experimental investigation into the sealing capability of naturally fractured shale caprocks to supercritical carbon dioxide flow geological storage of co2 is considered a solution for reducing the excess co2 released into the atmosphere low permeability caprocks physically trap co2 injected into underlying porous reservoirs injection leads to increasing pore pressure and reduced effective stress increasing the likelihood of exceeding the capillary entry pressure of the caprocks and of caprock fracturing assessing on how the different phases of co2 flow through caprock matrix and fractures is important for assessing co2 storage security fractures are considered to represent preferential flow paths in the caprock for the escape of co2 here we present a new experimental rig which allows 38 mm diameter fractured caprock samples recovered from depths of up to 4 km to be exposed to supercritical co2 scco2 under in situ conditions of pressure temperature and geochemistry in contrast to expectations the results indicate that scco2 will not flow through tight natural caprock fractures even with a differential pressure across the fractured sample in excess of 51 mpa however below the critical point where co2 enters its gas phase the co2 flows readily through the caprock fractures this indicates the possibility of a critical threshold of fracture aperture size which controls co2 flow along the fracture

capacity and suitability assessment of deep saline aquifers for co2 sequestration in the bohai bay basin east china co2 sequestration in deep saline aquifers has proven to be one of the most promising options to reduce anthropogenic co2 emissions sedimentary basins are chosen as targets of co2 sequestration due to the existence of deep saline aquifers this paper presents the first systematic investigation on the occurrence and characteristics of potential reservoirs for co2 sequestration in deep saline aquifers in the bohai bay basin bbb and offers detailed estimates on the storage capacity within the depth range from 800 to 3500 m a preliminary suitability assessment for preferential sites is also presented geological analyses show that deep saline aquifers in guantao formation ng of neogene dongying ed and shahejie formations es1 es2 es3 es4 of paleogene are potential reservoirs deep saline aquifers in the bbb may accommodate about 3922 mt co2 with 50 confidence level according to a modified cslf carbon sequestration leadership forum method the co2 storage capacity of individual depression varies from 65 mt liaohe depression to 934 mt liaodongwan bozhong depression the guantao formation ng of neogene is a regionally distributed reservoir with low tds total dissolved solids and favorable depth and thickness the capacity of which accounts for 84 of the total and is therefore considered as the most promising reservoir preliminary suitability assessment is carried out in terms of sedimentology tectonic stability geothermal conditions saline water characteristics potentially conflicting resources development as well as co2 emission sources the liaodongwan bozhong jiyang changwei and huanghua depressions are chosen as the most suitable sites for co2 storage jizhong and liaohe depressions are less suitable while linqing depression is not suitable due to its lower tectonic stability geological information and co2 emission sources although uncertainties exist the estimate in this study is significant for future study and implementation of co2 sequestration in the basin

status of co2 storage in deep saline aquifers with emphasis on modeling approaches and practical simulations carbon capture and storage ccs is the only viable technology to mitigate carbon emissions while allowing continued large scale use of fossil fuels the storage part of ccs involves injection of carbon dioxide captured from large stationary sources into deep geological formations deep saline aquifers have the largest identified storage potential with estimated storage capacity sufficient to store emissions from large stationary sources for at least a century this makes ccs a potentially important bridging technology in the transition to carbon free energy sources injection of co2 into deep saline aquifers leads to a multicomponent multiphase flow system in which geomechanics geochemistry and nonisothermal effects may be important while the general system can be highly complex and involve many coupled nonlinear partial differential equations the underlying physics can sometimes lead to important simplifications for example the large density difference between injected co2 and brine may lead to relatively fast buoyant segregation making an assumption of vertical equilibrium reasonable such simplifying assumptions lead to a range of simplified governing equations whose solutions have provided significant practical insights into system behavior including improved estimates of storage capacity easy to compute estimates of co2 spatial migration and pressure response and quantitative estimates of leakage risk when these modeling studies are coupled with observations from well characterized injection operations understanding of the overall system behavior is enhanced significantly this improved understanding shows that while economic and policy challenges remain co2 storage in deep saline aquifers appears to be a viable technology and can contribute substantially to climate change solutions

a 6 year amsu based climatology of upper level troughs and associated precipitation distribution in the mediterranean region 1 we present a novel climatology of upper tropospheric troughs and associated precipitation in the mediterranean region using 6 years 2001 2006 of advanced microwave sounding unit data troughs are more frequent or persistent during november through march in the whole of the mediterranean basin with up to 25 of days in the northwestern part of the basin the interannual variability of number of intrusions is stronger from september through june during summer the variability is reduced except in the nw region and no troughs were observed in the se region moderate precipitation occurs in at least 60 of the cases when an upper level trough is present with weak seasonal dependency in the southern mediterranean moderate precipitation is an ubiquitous feature and presents small year to year fluctuations the occurrence of deep convective rain associated with trough is lower around 50 and reduces to 20 in the northern part of the basin during winter this occurrence varies a lot with individual years especially in the southern mediterranean upper level troughs have more often a n s orientation but while no particular dependency of frequency of precipitation whether moderate or convective on their inclination was found the location of precipitation is generally favored downstream the north atlantic oscillation and scandinavia patterns were found to be the most important large scale circulation modes influencing the variability of number of intrusions but the east atlantic west russia and east atlantic patterns are also important in the southeast region

fracture healing and transport properties of wellbore cement in the presence of supercritical co2 this paper investigates the process and rate of carbonation reaction of class a wellbore cement exposed to co2 saturated solution at confined conditions similar to those employed in geological storage of co2 the main goal was to investigate whether reaction improves or degrades the sealing healing capacity of fractured type a cement plugs batch reaction experiments were performed for up to three months on both intact and fractured class a portland cement cylinders at a constant confining pressure of 30 mpa a temperature of 80 c and a co2 pressure of 10 mpa the experiments were carried out on water saturated samples exposing them to the supercritical co2 at one end all samples were jacketed in sleeves to seal them from the high pressure confining medium the results indicate that cement carbonation front advanced in time leading to a densification of the material extrapolation of the reaction rates to 1 year period indicates a carbonation depth of about 1 38 mm and about 7 56 mm after 30 years of exposure to co2 saturated solution thermogravimetric analyses scanning electron microscopy observations and permeability measurements indicate that carbonation of wellbore cement leads to a decrease of the porosity of the material on the reaction front and moreover has the potential for healing pre existent fractures and for improving the sealing properties of good quality cement samples in time at reservoir conditions

simulation of co2 plume movement in multilayered saline formations through multilayer injection technology in the ordos basin china deep saline aquifers still remain a significant option for the disposal of large amounts of co2 from the atmosphere as a means of mitigating global climate change the small scale carbon capture and sequestration demonstration project in ordos basin china operated by the shenhua group is the only one of its kind in asia to put the multilayer injection technology into practice this paper aims at studying the influence of temperature injection rate and horizontal boundary effects on co2 plume transport in saline formation layers at different depths and thicknesses focusing on the variations in co2 gas saturation and mass fraction of dissolved co2 in the formation of brine in the plume s radial three dimensional field around the injection point and interlayer communication between the aquifer and its confining beds of relatively lower permeability the study uses the eco2n module of tough2 to simulate flow and pressure configurations in response to small scale co2 injection into multilayer saline aquifers the modelling domain involves a complex multilayer reservoir caprock system comprising of a sequence of sandstone aquifers and sealing units of mudstone and siltstone layers extending from the permian shanxi to the upper triassic liujiagou formation systems in the ordos basin simulation results indicate that co2 injected for storage into deep saline aquifers cause a significant pressure perturbation in the geological system that may require a long duration in the post injection period to establish new pressure equilibrium the multilayer simultaneous injection scheme exhibits mutual interference with the intervening sealing layers especially when the injection layers are very close to each other and the corresponding sealing layers are thin the study further reveals that injection rate and temperature are the most significant factors for determining the lateral and vertical extent that the co2 plume reaches and which phase and amount will exist at a particular time during and after the injection in general a large number of factors may influence the co2 water fluid flow system considering the complexity in the real geologic sequence and structural configurations therefore optimization of a co2 injection scheme still requires pursuance of further studies

the pennsylvanian pewamo formation and associated haybridge strata toward the resolution of the jurassic ionia red bed problem in the michigan basin u s a abstract two distinct and newly recognized formation scale stratigraphic units predominantly red bed sandstones and shales are found on the surface and in the shallow subsurface of the central michigan region here we use core field and laboratory observations to document these strata which we propose as one new formation the pewamo formation the pewamo formation consists of eolian quartz sandstones with red coloration due to iron oxide diagenesis and interbedded interdune lacustrine siliciclastic mudstones we also describe for the first time the haybridge strata which contains red sandstones red and gray shales and coal and has plant fossils and paleosol features macroscopic plant fossils and palynomorphs suggest a pennsylvanian age for both units these newly described continental deposits provide data about past environments life and climate for the late carboniferous of michigan in addition this study is an evaluation of michigan s controversial jurassic red beds and ionia sandstone

capillarity and wetting of carbon dioxide and brine during drainage in berea sandstone at reservoir conditions the wettability of co2 brine rock systems will have a major impact on the management of carbon sequestration in subsurface geological formations recent contact angle measurement studies have reported sensitivity in wetting behavior of this system to pressure temperature and brine salinity we report observations of the impact of reservoir conditions on the capillary pressure characteristic curve and relative permeability of a single berea sandstone during drainage co2 displacing brine through effects on the wetting state eight reservoir condition drainage capillary pressure characteristic curves were measured using co2 and brine in a single fired berea sandstone at pressures 5 20 mpa temperatures 25 50 c and ionic strengths 0 5 mol kg 1 nacl a ninth measurement using a n2 water system provided a benchmark for capillarity with a strongly water wet system the capillary pressure curves from each of the tests were found to be similar to the n2 water curve when scaled by the interfacial tension reservoir conditions were not found to have a significant impact on the capillary strength of the co2 brine system during drainage through a variation in the wetting state two steady state relative permeability measurements with co2 and brine and one with n2 and brine similarly show little variation between conditions consistent with the observation that the co2 brine sandstone system is water wetting and multiphase flow properties invariant across a wide range of reservoir conditions

petrology of gedrite bearing rocks in mid crustal ductile shear zones from the eastern ghats belt india a suite of metapelitic basic and quartzofeldspathic rocks intruded by enderbitic gneiss from the southernmost tip of the eastern ghats belt india and metamorphosed at c 750 800 c 6 kbar were subjected to repeated ductile shear deformation hydration cooling and accompanying alkali metasomatism along narrow shear zones gedrite bearing assemblages developed in the shear zones traversing metapelitic rocks interpretation of the reaction textures in an appropriate p t grid in the system fmash an isothermal isobaric h2o na2o grid in the system nfmash and geothermobarometric data suggest a complex evolutionary history for the gedrite bearing parageneses initially gedrite bearing assemblages were produced due to increase in na2o at nearly constant but high h2o accompanying cooling gedrite was partially destabilized to orthopyroxene albite due to progressively increasing na2o during further cooling and at increased h2o a second generation of gedrite appeared in the rocks

classification of cyclone tracks over the apennines and the adriatic sea abstract cyclones that appear in the adriatic sea basin strongly influence the climate and weather conditions in the area in particular apart from the usually mild climate cyclone activity in the adriatic and the central mediterranean sea provide both the main hydrological forcing and the trigger mechanisms for a range of extreme weather phenomena therefore a basic understanding of the cyclogenesis over the adriatic sea is essential in particular the classification of different types of cyclogenesis in the area is fundamental because it will help the understanding and prediction of the relevant weather phenomena in this study based on the analysis of the 4 yr 2002 05 operational european centre for medium range weather forecasts t511 dataset various types of cyclone tracks are classified and the mesocyclogenesis areas in the vicinity of the adriatic basin are isolated this analysis indicates that the following four types of cyclogenesis over the adriatic sea can be identified 1 type a cycl

ultrahigh temperature stability of sapphirine and kornerupine in ganguvarpatti granulite madurai block southern india

severe flooding over central and southern greece associated with pre cold frontal orographic lifting an extreme rainfall event associated with a cold front which occurred on 11 12 january 1997 over greece is investigated through observational analysis and numerical simulations the analysed storm system produced large amounts of rainfall with devastating impacts over central and southern greece where at some sites 24 hour accumulated precipitation exceeded 300 mm the model analysis was performed with the three dimensional non hydrostatic colorado state university regional atmospheric modeling system the model results caught the larger scale features present in the observational analyses while developing more realistic finer scale features sensitivity tests are also performed in order to investigate the role of the topography of the greek peninsula on the enhancement of convection indeed the orientation of the flow was optimal for advection of moist air with a maximized fetch over the sea and at an angle of impact optimum for orographic lifting ahead of the main topographic axes of continental greece

palaeogeographic mapping to understand the hydrocarbon and co2 storage potential of the post rift warnbro group offshore vlaming sub basin southern perth basin australia abstract the lower cretaceous gage sandstone and south perth shale are a prospective reservoir seal pair in the warnbro group offshore vlaming sub basin western australia plays include post breakup pinch outs and 4 way dip closures a sequence stratigraphic analysis incorporating seismic interpretation well log analysis and new biostratigraphic data characterised the reservoir seal pair palaeogeographic mapping reveals multiple regressive transgressive cycles which infilled the central palaeodepression on the valanginian unconformity within the deltaic south perth supersequence the gage lowstand fan lithostratigraphically referred to as the gage sandstone is a sand rich submarine fan system and ranges from canyon confined inner fan to basin plain middle fan deposits major sediment contributions were from north south trending canyons adjacent to the mandurah terrace detailed seismic facies mapping and well log analysis of the gage lowstand fan show that distal middle fan sand sheets and stacked channelised sands in the inner fan may provide an extensive reservoir of good to excellent quality seal quality varies greatly and may explain the lack of exploration success at some structural closures a re evaluation of the regional seal determined the extent of deepwater shale facies that provides an effective seal for the underlying submarine fans 3d geological modelling confirms that the reservoir is suitable for hydrocarbon entrapment and co 2 storage migration path analysis identified the presence of multiple structural and stratigraphic closures at the top of the reservoir previous petroleum systems modelling concluded that some source rock maturation probably post dates deposition of the effective seal thereby allowing structural closures to be charged with hydrocarbons uncertainties potentially comprising hydrocarbon preservation and co 2 storage include reactivation of large syn rift faults that may breach top seal the potential absence of base seal effective seal thickness and reservoir thickness and quality

mesozoic intraplate deformation in the southern part of the central european basin results from large scale 3d modelling abstract the central european basin is an intracontinental basin that initially formed due to long lasting thermal subsidence accompanied with several tectonic phases of extension during mesozoic times locally thick evaporites were incorporated in the deformation and led to the formation of detached structures salt pillows and diapirs at the end of the late cretaceous the formation of sub basins and half grabens became interrupted by a short term event of contraction especially along the northern and southern edges of the basin lithospheric shortening resulted in basin inversion and the uplift of large basement blocks hence the present day s structural framework shows a complex pattern of kinematically and chronologically variable structures herein we unravelled these structures for the altmark region in northern saxony anhalt central germany we used regional depth maps reflection seismics and borehole data analysed by use of large scale subsurface mapping and 3d modelling techniques to completely re evaluate the structures in the late palaeozoic to cenozoic sedimentary basin succession our results show a high variability of tectonic structures narrow and distributed in parts reactivated normal fault zones huge inverted basins thin skinned thrust faults detachment folds and large basement thrusts the style of deformation significantly changed during the region s evolution this is indicated by particular structural kinematic thermal and rheological conditions which existed for the individual phases of basin formation and inversion and probably persist until today

influence of the flow rate on dissolution and precipitation features during percolation of co2 rich sulfate solutions through fractured limestone samples abstract calcite dissolution and gypsum precipitation are expected to occur when injecting co2 in a limestone reservoir with sulfate rich resident brine if the reservoir is fractured these reactions will take place mainly in the fractures which serve as preferential paths for fluid flow as a consequence the geometry of the fractures will vary leading to changes in their hydraulic and transport properties in this study a set of percolation experiments which consisted of injecting co2 rich solutions through fractured limestone cores was performed under p 150 bar and t 60 c flow rates ranging from 0 2 to 60 ml h and sulfate rich and sulfate free solutions were used variation in fracture volume induced by calcite dissolution and gypsum precipitation was measured by x ray computed microtomography xcmt and aqueous chemistry an increase in flow rate led to an increase in volume of dissolved limestone per unit of time which indicated that the calcite dissolution rate in the fracture was transport controlled moreover the dissolution pattern varied from face dissolution to wormhole formation and uniform dissolution by increasing the flow rate i e pe from 1 to 346 fracture permeability always increased and depended on the type of dissolution pattern

crustal trajectory of sapphirine bearing granulites from ganguvarpatti south india evidence for an isothermal decompression path abstract ganguvarpatti is part of a precambrian terrane characterized by granulite facies rocks including charnockites mafic granulites sapphirine bearing granulites leptynites and gneisses a sequence of reactions deduced from the multiphase reaction textures provide information on the metamorphic history of this area as they formed in response to decompression during uplift geothermobarometry and constraints from reaction textures define a segment of a p t path traversed by the granulites of ganguvarpatti near peak metamorphic conditions of c 800 c and 8 kbar were succeeded by a symplectitic stage at a significantly lower pressure c 700 c and 4 5 kbar documenting a nearly isothermal decompression p t path and rapid uplift c 12 km followed by cooling the presence of many fluid inclusions of extremely low density in the charnockites is consistent with a nearly isothermal uplift path attainment of a maximum pressure of c 8 kbar indicates c 27 km depth of burial during metamorphism this would imply a total crustal thickness of c 65 70 km at 2 6 2 5 ga such a profound crustal thickness and a clockwise decompressive p t path is interpreted as a consequence of tectonic thickening of crust accomplished by collision tectonics of the southern granulite terrane against the dharwar craton along the palghat cauvery shear zone via northward subduction

pore scale imaging of geological carbon dioxide storage under in situ conditions 1 while geological carbon dioxide co2 storage could contribute to reducing global emissions it must be designed such that the co2 cannot escape from the porous rock into which it is injected an important mechanism to immobilize the co2 preventing escape is capillary trapping where co2 is stranded as disconnected pore scale droplets ganglia in the rock surrounded by water we used x ray microtomography to image at a resolution of 6 4 m the pore scale arrangement and distribution of trapped co2 clusters in a limestone we applied high pressures and temperatures typical of a storage formation while maintaining chemical equilibrium between the co2 brine and rock substantial amounts of co2 were trapped with an average saturation of 0 18 the cluster sizes obeyed a power law distribution with an exponent of approximately 2 1 consistent with predictions from percolation theory this work confirms that residual trapping could aid storage security in carbonate aquifers

assessment and geological characterisation of the co2crc otway project co2 storage demonstration site from prefeasibility to injection abstract the co2crc otway project located in south eastern australia has demonstrated geological storage of co 2 in a depleted natural gas field prior to injection a comprehensive site characterisation study established that the site should meet the requirements of safe and effective storage in contrast to the conventional methods applied to characterising oil and gas reservoirs for production purposes co 2 storage site assessments place greater emphasis on injectivity capacity and long term containment the site location was assessed in the context of accessibility for monitoring activities and impact on local communities and natural resources additional well log data and cores were acquired from the gas field in conjunction with the drilling of the crc 1 injector well in order to reduce the uncertainty surrounding the geological heterogeneity of the reservoir capacity of the seal to retain co 2 fault seal geomechanics and regional hydrodynamics specialised core analysis revealed that small scale sedimentary features related to depositional environment impact reservoir quality co 2 trapping and plume migration behaviour based on these effects a depositional model was established to better understand storage potential away from well control finally a nearby gas storage facility provided a valuable analogue for the project and added confidence that the co2crc otway project site would be suitable to inject store and contain co 2 within the technological and economical limits of the project following the injection period long term monitoring of the reservoir as well as the overlying aquifers soil groundwater and the atmosphere above the site have confirmed the storage concept is effective and that the co 2 is safely contained as a result the site characterisation methodology serves as an example for others contemplating co 2 storage into depleted gas fields

the application of single zircon evaporation and model nd ages to the interpretation of polymetamorphic terrains an example from the proterozoic mobile belt of south india the technique of single zircon dating from the thermal evaporation of 207pb 206pb kober 1986 1987 provides a means of dating successive periods of growth and nucleation of zircons in polymetamorphic assemblages in contrast nd model ages may provide a measure of the period of crustal residency for the sample or its protolith these two techniques have been combined to elucidate the tectonic history of the proterozoic mobile belt of southern india exposed south of the palghat cauvery shear zone that marks the southern boundary of the archaean craton of karnataka the two main tectonic units of this mobile belt comprise the madurai and trivandrum blocks both of which are characterised by massive charnockite uplands and low lying polymetamorphic metasedimentary belts that have undergone a complex tectonic history throughout the proterozoic evidence for early palaeoproterozoic magmatism is restricted to the madurai block where single zircon evaporation ages from a metagranite 2436 4 ma are similar to model nd ages from a range of lithologies suggesting crustal growth at that time the trivandrum block to the south of the achankovil shear zone is comprised of the kerala khondalite belt the nagercoil charnockites and the achankovil metasediments single zircon evaporation ages together with conventional zircon and garnet chronometry suggest that all three units underwent upper amphibolite facies metamorphism at 1800 ma an event unrecorded in the metagranite from the madurai block this implies that the madurai and trivandrum blocks represent distinct terrains throughout the palaeoproterozoic model nd ages from the achankovil metasediments are much younger 1500 1200 ma than those from the adjacent kerala khondalite belt and madurai blocks 3000 2100 ma but there is no evidence for zircon growth in these metasediments during the mesoproterozoic hence the comparatively young model nd ages of the metasediments are indicative of a mixed provenance rather than a discrete period of crustal growth zircon overgrowths from the madurai block 547 17 ma and achankovil metasediments 530 21 ma suggest that all tectonic units of the proterozoic mobile belt of south india shared the same metamorphic history from the early palaeozoic this event has been recognised in the basement lithologies of sri lanka and east antarctica confirming that the constituent terrains of east gondwana had assembled by this time

hydrogeochemical processes in clastic sedimentary rocks south korea a natural analogue study of the role of dedolomitization in geologic carbon storage abstract for long term mineral trapping of sequestered co 2 in deep saline aquifers base cations such as ca 2 and mg 2 are essential as a natural analogue study of geologic carbon storage in deep aquifers hosted in sedimentary formations we examined the hydrochemistry of sulfate rich up to 1140 mg l so 4 2 and moderately high p co 2 10 1 1 to 10 2 4 atm groundwater in a cretaceous non marine sedimentary basin in south korea with the objective to elucidate water rock interactions controlling the concentrations and behavior of base cations principal component analysis of the acquired hydrochemical data indicated that dissolution of carbonates calcite and dolomite and evaporite minerals halite and gypsum controls the chemical composition of groundwater resulting in substantial increases of the concentration s of ca 2 mg 2 na cl so 4 2 and total dissolved solids tds in deep groundwater na versus cl and ca 2 mg 2 versus hco 3 so 4 2 plots provided evidence for dissolution of halite and gypsum progressively increasing 34 s values of dissolved so 4 2 from 15 1 to 19 2 with increasing sulfate concentrations indicated gypsum dissolution ion ion plots esp mg 2 ca 2 ca 2 so 4 2 and mg 2 so 4 2 and saturation indices of calcite dolomite and gypsum suggest that the groundwater chemistry esp the concentrations of ca 2 and mg 2 is controlled by dedolomitization driven by gypsum dissolution groundwater in the study area does not reach complete equilibrium with respect to calcite and dolomite because of gypsum dissolution which controls the mg 2 ca 2 ratios of groundwater continued calcite precipitation triggered by an excess ca supply from gypsum dissolution reduces the concentrations of dissolved inorganic carbon dic in groundwater the increase of 13 c dic values from 11 1 to 6 5 concomitantly with increasing sulfate concentration was explained via geochemical modeling by dedolomitization under the rate constant ratio of about 0 038 between dolomite and calcite the model results agree well with the observed mg 2 ca 2 ratios and further suggest a potential increase of the void volume in the aquifer through dedolomitization by about 0 72 cm 3 l based on this analogue we suggest that dedolomitization in concert with dissolution of gypsum may constitute an important process releasing base cations for mineral trapping of injected co 2 in non marine clastic sedimentary strata containing carbonates and gypsum in south korea and elsewhere

petrology and microthermometry of aluminous rocks in the botswanan limpopo central zone evidence for isothermal decompression and isobaric cooling phase analysis in the model k2o poor aluminous rock system fmash illustrates the following sequence of reactions during retrograde metamorphism in the botswanan limpopo central zone opx sil qtz crd opx sil spr crd grt qtz opx crd opx crd w ged qtz grt opx crd w ged and grt qtz w ged crd a quantitative petrogenetic grid with phase relations shows that sapphirine results from nearly isothermal decompression in the quartz undersaturated portions of the grid and that gedrite formation by reactions 4 6 records isobaric cooling from high temperature c 800 c after the decompression conditions for hydration in the western part of the area were 700 800 c and c 6 kbar based on microthermometric data and the available garnet cordierite geothermometer on the basis of these conditions and predicted thermodynamic properties of gedrite phase relations in t xmg space were constructed to investigate the isobaric cooling event the results are in good agreement with the hydration p t path further the t xmg topologies show that hydration of orthopyroxene in the central part of the area reaction 4 occurred at about 800 c and c 5 kbar therefore we conclude that the botswanan limpopo central zone has suffered isothermal decompression similar to the central zone in south africa and zimbabwe followed by isobaric cooling the isobaric cooling event in the western at c 6 kbar and central at c 5 kbar parts of the area commenced at nearly the same temperature c 800 c and appear to be consistent with a tectonic model that involved westward movement thrusting of the central zone