Journal articles on the topic 'Preuss Sandstone'

Geochemical and rock magnetic studies, undertaken to determine the cause of magnetic anomalies over Cement oil field (Anadarko basin, Oklahoma), Simpson oil field (North Slope basin, Alaska), and the Wyoming‐Idaho‐Utah thrust belt, have revealed different magnetic sources developed under different sedimentologic, geochemical, and structural settings. At Cement, ferrimagnetic pyrrhotite ([Formula: see text]), typically intergrown with more abundant, nonmagnetic pyrite ([Formula: see text]), formed as a result of hydrocarbon seepage. Sulfur isotopic data indicate that sulfur in the Fe‐S minerals was probably derived from two different sources: (1) isotopically heavy, thermochemical [Formula: see text] in petroleum, and (2) isotopically light [Formula: see text] generated by sulfate‐reducing bacteria that derived metabolic energy from leaking hydrocarbons or organic compounds derived from hydrocarbons. Although pyrrhotite may make a minor contribution to the reported total magnetic field anomalies at Cement, the measured anomalies are probably mostly caused by man‐made features such as buried well casings and pipelines. Magnetite, found in well cuttings from Cement and previously considered the source of the anomalies, is contamination from drilling. At Simpson, ferrimagnetic greigite ([Formula: see text]) is concentrated locally in Upper Cretaceous beds. A preliminary geochemical study reveals a complicated picture in which early diagenetic chemical and mineralogic changes are variably overprinted by later epigenetic alterations, perhaps related to hydrocarbon seepage. The greigite probably formed at different times from sulfate reduction by bacteria that used either organic compounds derived from hydrocarbons or detrital organic matter, or both, as food sources. Magnetic‐property studies suggest the natural remanent magnetization of greigite‐bearing rocks may contribute to the magnetic anomalies. In the thrust belt, the Middle Jurassic Preuss Sandstone has magnetizations as much as 0.76 A/m (average 0.14 A/m) west of the Absaroka fault where aeromagnetic anomalies locally correspond to exposures of the Preuss and much lower magnetizations (average [Formula: see text]) east of the Absaroka fault. The magnetization is carried by rounded titanium‐bearing detrital magnetite, commonly concentrated along heavy‐mineral laminations. Carbon isotopic compositions of calcite cement (−2.4 to +1.5 per mil) reflect an absence of organic carbon in the calcite and thus suggest that hydrocarbon had no role in the preservation of the detrital magnetite. Our results show that abiologic and biologic mechanisms can generate different magnetic sulfide minerals in zones of sulfidic hydrocarbon seepage. More commonly, sulfidic seepage could either diminish magnetization by replacement of detrital magnetic minerals with nonmagnetic sulfide minerals, or it would have no effect on magnetization if such detrital minerals were originally absent. An important negative result is the absence of abundant secondary (diagenetic) magnetite in the seepage environments. Although secondary magnetite occurs in some biodegraded crude oils, concentrations of such magnetite capable of producing aeromagnetic anomalies have not been documented.

In order to study the damage characteristics of the yellow sandstone containing pores under the freeze-thaw cycle, the uniaxial compression test of saturated water-stained yellow sandstones with different freeze-thaw cycles was carried out by rock servo press, the microstructure was qualitatively analyzed by Zeiss 508 stereo microscope, and the microdamage mechanism was quantitatively studied by using specific surface area and pore size analyzer. The mechanism of weakening mechanical properties of single-hole yellow sandstone was expounded from the perspective of microstructure. The results show the following. (1) The number of freeze-thaw cycles and single-pore diameter have significant effects on the strength and elastic modulus of the yellow sandstone; the more the freeze-thaw cycles and the larger the pore size, the lower the strength of the yellow sandstone. (2) The damage modes of the yellow sandstone containing pores under the freeze-thaw cycle are divided into five types, and the yellow sandstone with pores is divided into two areas: the periphery of the hole and the distance from the hole; as the number of freeze-thaw cycles increases, different regions show different microscopic damage patterns. (3) The damage degree of yellow sandstone is different with freeze-thaw cycle and pore size. Freeze-thaw not only affects the mechanical properties of yellow sandstone but also accelerates the damage process of pores. (4) The damage of the yellow sandstone by freeze-thaw is logarithmic function, and the damage of the yellow sandstone is a power function. The damage equation of the yellow sandstone with pores under the freezing and thawing is a log-power function nonlinear change law and presents a good correlation.

Abstract The paper describes the methodology of measurements in the GTA 20-32 triaxial press. The deformation behaviour of two different types of rocks was compared: - gypsum with plastic deformation even at lower confining pressure, - Carboniferous sandstone with brittle failure even at the highest confining pressure. The influence of gypsum layering was studied as well. The experimental results show that the deformation and strength properties of the gypsum in the triaxial state of stress do not significantly depend on the orientation of axial stress to the observed layering.

Abstract The poorly cemented Ciężkowice poorly sorted sandstone and the compact Mucharz fine grain sandstone have been laboratory tested at the triaxial compressing conditions in thermo-pressurized chamber of a rigid press MTS-815. The confining pressure: P = σ2 = gσ3 range from 0 to 96 MPa and the temperature: T from 22°C to 120°C (simulated 500 m intervals from the surface to the depth of 3500 m). During (the) each test, the characteristics of deformation and the elastic wave velocity paths were simultaneously monitored. The volume density and longitudinal wave velocity showed a non-linear increase with the progress of simulated depth, a volume density growth by 1.6 to 4.0%, and the elastic wave velocity up to 250% of the primary value (surface condition), dependable on loading path, phase of deformation, and varying type of lithology. That may lead to wide error margin in a determination of rock’s engineering properties and also create discrepancies between the static parameters of rocks (Est ,gνst ) determined by standard laboratory load tests, and the dynamic parameters (Ed, νd ) determined from the wave velocity and volume density

Summary Fluid-loss control is an essential property of oil-based mud (OBM) that can affect the success of drilling operations. This paper presents an investigation of the mitigation of lost circulation in OBM by use of leakoff-control-additive gilsonite. A simple physical model was developed to describe the static-filtration process considering the formation and properties of the filter cake. Both high-pressure/high-temperature (HP/HT) American Petroleum Institute (API) press and core-flow-filtration experiments were performed to evaluate the leakoff behavior of OBM. Core-filtration experiments were carried with the aid of a computerized-tomography (CT) scanner to monitor the invasion of the filtrate into the sandstone core at time intervals. In the long time limit, the model predicts that the fluid loss follows the classical Carter equation; that is, the volume of leakoff increases as the square root of time for the static filtration through a filter paper and through the sandstone core. Dual-mode filtration diminishes the rate of fluid loss considering the effect of emulsion. The model also provides a relation between pressure drop and filtrate rate, which can be used to estimate the permeability of filter cake in the experiment. The leakoff behavior with additive observed in the experiment is well-explained by the microstructure of rapid-buildup filter cake, which is mainly responsible for the control of fluid loss. The role of different components of OBM, such as solid particles, emulsion droplets, and additives, is discussed in light of our observations.

The rock geomechanical properties are the key parameters for designing the drilling and fracturing operations and for programing the geomechanical earth models. During drilling, the horizontal-section drilling fluids interact with the reservoir rocks in different exposure time, and to date, there is no comprehensive work performed to study the effect of the exposure time on the changes in sandstone geomechanical properties. The objective of this paper is to address the exposure time effect on sandstone failure parameters such as unconfined compressive strength, tensile strength, acoustic properties, and dynamic elastic moduli while drilling horizontal sections using barite-weighted water-based drilling fluid. To simulate the reservoir conditions, Buff Berea sandstone core samples were exposed to the drilling fluid (using filter press) under 300 psi differential pressure and 200 °F temperature for different exposure times (up to 5 days). The rock characterization and geomechanical parameters were evaluated as a function of the exposure time. Scratch test was implemented to evaluate rock strength, while ultrasonic pulse velocity was used to obtain the sonic data to estimate dynamic elastic moduli. The rock characterization was accomplished by X-ray diffraction, nuclear magnetic resonance, and scanning electron microscope. The study findings showed that the rock compression and tensile strengths reduced as a function of exposure time (18% and 19% reduction for tensile strength and unconfined compression strength, respectively, after 5 days), while the formation damage displayed an increasing trend with time. The sonic results demonstrated an increase in the compressional and shear wave velocities with increasing exposure time. All the dynamic elastic moduli showed an increasing trend when extending the exposure time except Poisson’s ratio which presented a constant behavior after 1 day. Nuclear magnetic resonance results showed 41% porosity reduction during the five days of mud interaction. Scanning electron microscope images showed that the rock internal surface topography and internal integrity changed with exposure time, which supported the observed strength reduction and sonic variation. A new set of empirical correlations were developed to estimate the dynamic elastic moduli and failure parameters as a function of the exposure time and the porosity with high accuracy.

AbstractPrecise measurement of the content and the layer charge of illite and smectite is an important aspect of the mineralogical calibration of geophysical well logs and of the evaluation of mechanical and chemical properties of sedimentary rocks. Ate chnique for obtaining such measurements was developed during mineralogical studies of the Miocene clastic rocks from the Carpathian Foredeep. X-ray diffraction (XRD), chemical, cation exchange capacity (CEC), H2O sorption, and ethylene glycol monoethyl ether (EGME) sorption data were obtained for 65 samples of sandstones, shales and carbonates. The illite + smectite sum, involving all detected 2:1 minerals (smectite, illite-smectite, illite, glauconite and muscovite) was measured by XRD. The content of the illitic component was evaluated separately using % K2O and accounting for % K2O in K-feldspar. The content of the smectitic component was estimated from EGME retention using the reference data for a smectite standard, and from CEC assuming the smectitic layer charge of 0.41/O10(OH)2 (Środoń et al., in press). All these measurements produced very consistent results.

Annotation In the work, studies were carried out on the effect of the dimensions of rock samples and the shape of their end faces on the tensile strength limits. Sandstones, aleurolites and their interlayers were tested. The core diameter was 36-78 mm, prevailing 50-70 mm. Rocks are mainly me- dium- and fine-grained. The fracture of cores into pieces took place along thin layers of carbonaceous materials, aleurolites, cracks and cleavage, in places of accumulation and plaque of carbonaceous, carbonate and other weak substances in the form of continuous films, scattered spots and debris. All tests were carried out on the press in accordance with the recommenda- tions of the current GOST, samples were divided by applying a load along the generatrix. It was found that the tensile strength of the test samples var- ied from 0.15 to 21 MPa. The results obtained proved conclusively that cores can be used to solve production and technical problems without pre- liminary treatment of their end surfaces at the ratio of heights to diameters from 0.31 to 1.6. This will allow to increase the volume of tests of samples taken in wells by 60%, and obtain reliable information and thus more fully and reliably substantiate geomechanical conditions, Attachment and protec- tion of mine workings and optimal angles of slopes of quarry sides and ledges at open method of coal mining. This issue has been little studied and requires further research in every geological-economic region of Kuzbass.

The launch of a new journal is appropriately like a space mission. It is the result of a scientific need, the inspiration of a group of committed scientists and technologists, a series of draft proposals, an approved mission protocol, and a launch. Today is the launch day for a journal whose remit has only recently consolidated from diverse disciplines. Cambridge University Press has an international reputation for astronomy. To this we add extreme biology and its associated environmental research to integrate astrobiology as: ‘the study of the origin, evolution, adaptation and distribution of past and present life in the Universe’.Astrobiology has three main themes: (1) Origin, evolution and limits of life on Earth; (2) Future of life, both on Earth and elsewhere; (3) Search for habitats, biomolecules and life in the Solar System and elsewhere. These fundamental concepts require the integration of various disciplines, including biology (especially microbiology), chemistry, geology, palaeontology, and the physics of atmospheres, planets and stars. We must also keep our minds wide open about the nature and limits of life. We can safely assume a carbon-based system within Solar Systems as we know them, but our concept of habitable zones expands yearly. We were taught that only the spores of certain bacilli could survive temperatures above the boiling point of water, and yet we now know that the deep-sea vent microbe Pyrolobus can survive an hour at 121 °C, which is the temperature used for sterilising medical instruments. We know of cyanobacteria which can not only live inside deep-frozen Antarctic rocks but also survive on roof-tops in Jerusalem at 80 °C. The bacterium Deinococcus radiodurans tolerates lethal doses of nuclear radiation, and cyanobacteria inside Antarctic desert sandstone receive so little moisture that their carbon turnover time (from its fixation by photosynthesis to its release as carbon dioxide during respiration) is 10,000 years. Life is tolerant, adaptable and tenacious.

A detailed geophysical mapping project has been carried out by the Geological Survey of Denmark and Greenland (GEUS) in the offshore region south-west and west of Disko and Nuussuaq, central West Greenland as part of the preparations for the Disko West Licensing Round in 2006 (Fig. 1). The main purpose of the study was to evaluate the prospectivity of this almost 100 000 km2 large region, and to increase knowledge of basin evolution and the structural development. Results of the work, including a new structural elements map of the region and highlights of particular interest for hydrocarbon exploration of this area, are summarised below. Evidence of live petroleum systems has been recognised in the onshore areas since the beginning of the 1990s when seeps of five different oil types were demonstrated (BojesenKoefoed et al. 1999). Oil seeps suggesting widely distributed marine source rocks of Mesozoic age are particularly promising for the exploration potential (Bojesen-Koefoed et al. 2004, 2007). Furthermore, possible DHIs (Direct Hydro carbon Indicators) such as gas-clouds, pock marks, bright spots and flat events have been interpreted in the offshore region (Skaarup et al. 2000; Gregersen & Bidstrup in press). The evaluation of the region (Fig. 1) is based on all public and proprietary seismic data together with public domainmag- netic and gravity data. The seismic data (a total of c. 28 000 line km) are tied to the two existing offshore exploration wells in the region (Hellefisk-1 and Ikermiut-1). The study also incorporates information on sediments and volcanic rocks from onshore Disko and Nuussuaq (Fig. 2). Ten seismic horizons ranging from ‘mid-Cretaceous’ to ‘Base Quaternary’ (Fig. 2) have been interpreted regionally. Large correlation distances to wells, varying data quality and a thick cover of basalt in the north-eastern part of the region, add uncertainty in the regional interpretation, especially for the deeper horizons such as the ‘mid-Cretaceous’ equivalent to Santonian sandstone interval drilled in Qulleq-1 far south. Based on the seismic interpretation (Fig. 3) structural elements maps, horizon-depth maps and isopach maps have been produced; these maps, together with general stratigraphic knowledge on potential reservoirs, seals and source rocks (Fig. 2), provide important information for discussions of critical play elements including kitchens and structures.The existence of many large structures combined with the evidence of live petroleum systems has spurred the recent major interest for hydrocarbon exploration in the region.

Summary Effective interpretation of nuclear magnetic resonance (NMR) logs in shaly sands requires an understanding of the NMR contribution of clays. Of particular importance is the role of clays in the rapidly relaxing part of the NMR signal. In this study we measured the transverse relaxation time spectrum T2 of brine mixed with four clays (illite, smectite, kaolinite and glauconite) as a function of compaction. The Larmor frequency was 2 MHz and the echo spacing 0.16 ms. Mild compaction was achieved by centrifuging the clay slurry at three successive pressures ranging from 1 to 125 psi. Highly compacted samples were produced in a uniaxial press at six sequential pressures ranging from 500 to 16,000 psi. Each clay/brine slurry and its associated compacted sample showed a single peak in the T2 distribution spectrum. A second peak, which could be interpreted as the "clay-bound water," was never observed. The T2 peak position shifted to faster relaxation times as compaction increased, in proportion to the pore volume-to-surface ratio, Vp/As. The single peak and Vp/As proportionality are consistent with fast diffusion between the pore water and the monolayer of water on the clay surface. Surface relaxivity varied among the four clay minerals; glauconite, the clay with the highest magnetic susceptibility and iron content had the largest surface relaxivity. These results have important implications for the interpretation of NMR logs in shaly sands. Because of the effects of compaction and to a lesser extent the iron content on a clay's T2 peak position, it is not possible to independently determine clay type from some characteristic relaxation time. These data also imply that it is not feasible to estimate the cation exchange capacity from a single time cutoff of the T2 distribution without additional information such as laboratory measurements or other log data. Introduction Nuclear magnetic resonance logging has become an important tool in evaluating a formation's petrophysical properties. The unique and valuable advantage that NMR provides is pore size distribution information. No other logging method provides these data, which are the key component of log-based estimates of capillary-bound water volume, and permeability to flow.1 It has been proposed that NMR logging can be extended to estimate clay-bound water volumes, and identify clay minerals. Clay-bound water volume, important in determining water saturation from resistivity, has been correlated with the short-T2 less than 3 ms, porosity of 45 oilfield sandstones.2 Prammer et al.'s3 NMR clay/brine study found that the T2 distribution of clay-bound water associated with kaolinite and chlorite was greater than 3 ms, for illite it ranged between 1 and 2 ms and for smectite it was less than 1 ms. Observed T2 's were then used as an indicator of cation exchange capacity (CEC) because the number of available exchange sites is proportional to a clay's specific surface area. CEC is fundamental to converting bulk resistivity measurements into water saturation. The ability to estimate clay-bound water, and to identify the clay type, from NMR T2 distributions is not compatible with the ability to determine pore size distribution from the same data. In the first two cases the molecular diffusion rate of water in the pores must be slow, whereas in the latter case it is assumed to be fast. For example, consider a monolayer of water on the surface of room-dry clay. The monolayer has a short relaxation time, less than a millisecond, because of its interaction with the solid rock. Now fill the void space between the clay particles with water and consider the two extreme cases. In the first case, there is no molecular diffusion (exchange) between the surface-monolayer water and bulk water. Thus, the T2 spectrum will contain two separate peaks, one associated with the surface-monolayer water at less than a millisecond and one associated with the bulk water. In the opposite case, molecular diffusion is highly effective, and both the surface monolayer and bulk water have a common relaxation time, a single peak in the T2 spectrum with time constant: 1 T 2 = ρ s ( A s V p ) . ( 1 ) In this equation, which provides the fundamental connection between T2 and pore size, the term ?2 is the surface relaxivity parameter that indicates the capacity of the rock to cause the decay of magnetization in the water. Fig. 1 is a conceptual drawing of a T2 distribution for a sandstone that includes fluid in small pores that are typically associated with clays, capillary-bound and producible fluid. The objective of this study was to determine whether it is possible to infer a clay-bound water volume (peak or T2 cutoff), or clay type, and a pore size distribution from a NMR distribution spectrum. To achieve this goal we designed a set of experiments that examined the NMR relaxation of clay/brine mixtures at various compaction states. In contrast to shaly sands, the clay/brine mixtures provided the means to minimize the pore volume-to-surface ratio, so that any water-monolayer-related signal might be detected. The pore volume-to-surface ratio was easily varied through compaction, and the monomineralic samples enable the NMR response of individual clay types to be evaluated. We chose to study four clays commonly found in oil-bearing sedimentary environments: kaolinite, illite, smectite and glauconite. Experimental Procedures Samples of illite and glauconite were obtained from Wards Natural Science Establishment. Kaolinite and smectite (Ca Montmorillonite) were procured from ECC Intl., Georgia Kaolin Co. and the Source Clay Minerals Repository, respectively. Various physical properties of the clays were measured. Prior to the surface area and magnetic susceptibility measurements, the clays were dried overnight in a vacuum oven at 100°C. Surface area measurements were collected using the Micromeritics Gemini 2360 with nitrogen gas as adsorbate, and magnetic susceptibilities were measured on a Johnson Matthey MSB-AUTO magnetic susceptibility balance. CEC measurements were taken using the ammonium acetate/ammonium ion-specific electrode method by David K. Davies & Assoc., Inc. Table 1 is a summary of clay type, clay origin and clay physical properties. The samples were analyzed for mineralogy using dual-range Fourier transform infrared (FTIR) spectroscopy.4 In addition, the samples were sent to X-Ray Assay Laboratories for chemical analyses (Table 2). The mineralogy data indicate the presence of quartz in the illite sample. Consequently, a <2 ?m fraction of the sample was extracted by centrifuging the illite and drying the supernatant. The physical properties for these clays are in good agreement with those in the literature.5 The clay samples used for the room-dry and clay/brine mixture NMR experiments were kept at room temperature and at typical laboratory humidity conditions of 50%. To evaluate whether clay samples have a measurable NMR signal at room-dry conditions, samples were prepared by placing the clay in a test tube and sealing it off with a stopper and Teflon tape.

Streaming potential in rocks is the electrical potential developing when an ionic fluid flows through the pores of rocks. The zeta potential is a key parameter of streaming potential and it depends on many parameters such as the mineral composition of rocks, fluid properties, temperature etc. Therefore, the zeta potential is different for various rocks and liquids. In this work, streaming potential measurements are performed for five rock samples saturated with six different monovalent electrolytes. From streaming potential coefficients, the zeta potential is deduced. The experimental results are then explained by a theoretical model. From the model, the surface site density for different rocks and the binding constant for different cations are found and they are in good agreement with those reported in literature. The result also shows that (1) the surface site density of Bentheim sandstone mostly composed of silica is the largest of five rock samples; (2) the binding constant is almost the same for a given cation but it increases in the order KMe(Na+) < KMe(K+) < KMe(Cs+) for a given rock.References Corwin R. F., Hoovert D.B., 1979. The self-potential method in geothermal exploration. Geophysics 44, 226-245. Dove P.M., Rimstidt J.D., 1994. Silica-Water Interactions. Reviews in Mineralogy and Geochemistry 29, 259-308. Glover P.W.J., Walker E., Jackson M., 2012. Streaming-potential coefficient of reservoir rock: A theoretical model. Geophysics, 77, D17-D43. Ishido T. and Mizutani H., 1981. Experimental and theoretical basis of electrokinetic phenomena in rock-water systems and its applications to geophysics. Journal of Geophysical Research, 86, 1763-1775. Jackson M., Butler A., Vinogradov J., 2012. Measurements of spontaneous potential in chalk with application to aquifer characterization in the southern UK: Quarterly Journal of Engineering Geology & Hydrogeology, 45, 457-471. Jouniaux L. and T. Ishido, 2012. International Journal of Geophysics. Article ID 286107, 16p. Doi:10.1155/2012/286107. Kim S.S., Kim H.S., Kim S.G., Kim W.S., 2004. Effect of electrolyte additives on sol-precipitated nano silica particles. Ceramics International 30, 171-175. Kirby B.J. and Hasselbrink E.F., 2004. Zeta potential of microfluidic substrates: 1. Theory, experimental techniques, and effects on separations. Electrophoresis, 25, 187-202. Kosmulski M., and Dahlsten D., 2006. High ionic strength electrokinetics of clay minerals. Colloids and Surfaces, A: Physicocemical and Engineering Aspects, 291, 212-218. Lide D.R., 2009, Handbook of chemistry and physics, 90th edition: CRC Press. Luong Duy Thanh, 2014. Electrokinetics in porous media, Ph.D. Thesis, University of Amsterdam, the Netherlands. Luong Duy Thanh and Sprik R., 2016a. Zeta potential in porous rocks in contact with monovalent and divalent electrolyte aqueous solutions, Geophysics, 81, D303-D314. Luong Duy Thanh and Sprik R., 2016b. Permeability dependence of streaming potential coefficient in porous media. Geophysical Prospecting, 64, 714-725. Luong Duy Thanh and Sprik R., 2016c. Laboratory Measurement of Microstructure Parameters of Porous Rocks. VNU Journal of Science: Mathematics-Physics 32, 22-33. Mizutani H., Ishido T., Yokokura T., Ohnishi S., 1976. Electrokinetic phenomena associated with earthquakes. Geophysical Research Letters, 3, 365-368. Ogilvy A.A., Ayed M.A., Bogoslovsky V.A., 1969. Geophysical studies of water leakage from reservoirs. Geophysical Prospecting, 17, 36-62. Onsager L., 1931. Reciprocal relations in irreversible processes. I. Physical Review, 37, 405-426. Revil A. and Glover P.W.J., 1997. Theory of ionic-surface electrical conduction in porous media. Physical Review B, 55, 1757-1773. Scales P.J., 1990. Electrokinetics of the muscovite mica-aqueous solution interface. Langmuir, 6, 582-589. Behrens S.H. and Grier D.G., 2001. The charge of glass and silica surfaces. The Journal of Chemical Physics, 115, 6716-6721. Stern O., 1924. Zurtheorieder electrolytischendoppelschist. Z. Elektrochem, 30, 508-516. Tchistiakov A.A., 2000. Physico-chemical aspects of clay migration and injectivity decrease of geothermal clastic reservoirs: Proceedings World Geothermal Congress, 3087-3095. Wurmstich B., Morgan F.D., 1994. Modeling of streaming potential responses caused by oil well pumping. Geophysics, 59, 46-56.

The drilling mud program contains many tests such as filtration rate and filter cake properties to select the proper drilling fluid additives that yield the standard ranges of the viscosity, filtration rate, etc. However, the physical and chemical changes in the mud composition during the mud circulating will cause changes to the filter cake properties. The changes in the filter cake properties should be considered in the mud design program to prevent the problems associated with the change in the drilling fluid properties. For long horizontal wellbores penetrating plastic formations, the two sources of solids in filter cake are drilling chemical additives and formation cuttings (sand particles in the case of sandstone reservoir). This study focuses on the effect of introducing sand particles from the drilled—formations on the filter cake properties. Real drilling fluid samples from the field were collected at different location during drilling a 3600 ft of the horizontal section of a sandstone formation. Calcium Carbonate (CaCO3) was used as weighting material in this filed. The drilling fluid samples were collected at two different points: the flow line coming from the well after shale shaker and the flow line going to the well to verify the effect of separation stages on filter cake properties. The primary drilling fluid properties of the collected samples were measured such as density and rheological parameters. High pressure high temperature (HPHT) filter press was used to perform the filtration and filter cake experiments at 300 psi differential pressure and room temperature (25 °C). The mineralogy of the external filter cake formed by fluid loss cell is determined using SEM (scanning electron microscopy) and XRD (X-ray diffraction). Finally, solubility test was conducted to evaluate the effect of sand particles on filter cake removal (containing Calcium Carbonate as weighting material) using chelating agent: glutamic diacetic acid (GLDA) at pH 4. The results showed that for long horizontal sections, the effect of introducing sand particles to the composition of the filter cake can cause significant change to the properties of filter cake such as mineralogy, thickness, porosity, and permeability. For instant the thickness of filter cake increased about 40% of its original thickness when drilling sandstone formation in horizontal well due to fine sand particle settling. The filter cake porosity and permeability increment in the first 2000 ft part of the horizontal section was observed clearly due to the irregular shape of the drilling particles. However for the points after the first 2000 ft of horizontal lateral, the porosity and permeability almost remained constant. Increasing the sand content up to 20% degrade the dissolution rate of calcium carbonate in the GLDA (pH = 3.8) to 80% instead of 100%.

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Stemmerik, L., Dam, G., Noe-Nygaard, N., Piasecki, S., & Surlyk, F. (1998). Sequence stratigraphy of source and reservoir rocks in the Upper Permian and Jurassic of Jameson Land, East Greenland. Geology of Greenland Survey Bulletin, 180, 43-54. https://doi.org/10.34194/ggub.v180.5085 _______________ Approximately half of the hydrocarbons discovered in the North Atlantic petroleum provinces are found in sandstones of latest Triassic – Jurassic age with the Middle Jurassic Brent Group, and its correlatives, being the economically most important reservoir unit accounting for approximately 25% of the reserves. Hydrocarbons in these reservoirs are generated mainly from the Upper Jurassic Kimmeridge Clay and its correlatives with additional contributions from Middle Jurassic coal, Lower Jurassic marine shales and Devonian lacustrine shales. Equivalents to these deeply buried rocks crop out in the well-exposed sedimentary basins of East Greenland where more detailed studies are possible and these basins are frequently used for analogue studies (Fig. 1). Investigations in East Greenland have documented four major organic-rich shale units which are potential source rocks for hydrocarbons. They include marine shales of the Upper Permian Ravnefjeld Formation (Fig. 2), the Middle Jurassic Sortehat Formation and the Upper Jurassic Hareelv Formation (Fig. 4) and lacustrine shales of the uppermost Triassic – lowermost Jurassic Kap Stewart Group (Fig. 3; Surlyk et al. 1986b; Dam & Christiansen 1990; Christiansen et al. 1992, 1993; Dam et al. 1995; Krabbe 1996). Potential reservoir units include Upper Permian shallow marine platform and build-up carbonates of the Wegener Halvø Formation, lacustrine sandstones of the Rhaetian–Sinemurian Kap Stewart Group and marine sandstones of the Pliensbachian–Aalenian Neill Klinter Group, the Upper Bajocian – Callovian Pelion Formation and Upper Oxfordian – Kimmeridgian Hareelv Formation (Figs 2–4; Christiansen et al. 1992). The Jurassic sandstones of Jameson Land are well known as excellent analogues for hydrocarbon reservoirs in the northern North Sea and offshore mid-Norway. The best documented examples are the turbidite sands of the Hareelv Formation as an analogue for the Magnus oil field and the many Paleogene oil and gas fields, the shallow marine Pelion Formation as an analogue for the Brent Group in the Viking Graben and correlative Garn Group of the Norwegian Shelf, the Neill Klinter Group as an analogue for the Tilje, Ror, Ile and Not Formations and the Kap Stewart Group for the Åre Formation (Surlyk 1987, 1991; Dam & Surlyk 1995; Dam et al. 1995; Surlyk & Noe-Nygaard 1995; Engkilde & Surlyk in press). The presence of pre-Late Jurassic source rocks in Jameson Land suggests the presence of correlative source rocks offshore mid-Norway where the Upper Jurassic source rocks are not sufficiently deeply buried to generate hydrocarbons. The Upper Permian Ravnefjeld Formation in particular provides a useful source rock analogue both there and in more distant areas such as the Barents Sea. The present paper is a summary of a research project supported by the Danish Ministry of Environment and Energy (Piasecki et al. 1994). The aim of the project is to improve our understanding of the distribution of source and reservoir rocks by the application of sequence stratigraphy to the basin analysis. We have focused on the Upper Permian and uppermost Triassic– Jurassic successions where the presence of source and reservoir rocks are well documented from previous studies. Field work during the summer of 1993 included biostratigraphic, sedimentological and sequence stratigraphic studies of selected time slices and was supplemented by drilling of 11 shallow cores (Piasecki et al. 1994). The results so far arising from this work are collected in Piasecki et al. (1997), and the present summary highlights the petroleum-related implications.

Yellowhorn, Eldon and Kathy Lowinger. Turtle Island: The Story of North America’s First People. Annick Press, 2017.With this team effort, Eldon Yellowhorn, an archeologist and member of the Piikani First Nation, and Kathy Lowinger, a children’s author and former publisher, try, in part, to rectify a situation facing North America’s Indigenous peoples: “…generations unsure of their culture and disconnected from their identity” (102).Addressing this issue in ways appropriate for children is challenging; that the authors succeed to such a high degree is remarkable. At the outset, they reveal their strategy: Indigenous cultures can be understood through both myth and science. They explain their methods: historical timelines are established by means of carbon dating, archeological evidence, and documentation. They allow that “writing and paper making were not traditions among the peoples of North America,” but point out that before the arrival of the Spaniards in 1519, the people of Mesoamerica wrote “…thousands and thousands of books…The Spanish invaders burned whole libraries down.”Because both the geographic scope (the entire continent) and the chronological scope (possibly 19,000 years) of the book are vast, the authors are necessarily selective about the specific cultures they discuss. Their choices give a clear sense of Indigenous intelligence and inventiveness. For example, we learn how the Haida Gwaii built cedar canoes and harvested the sea; how the Plains People of Alberta used buffalo jumps such as the one at Head-Smashed-In to ensure their supply of meat, bone, hide and sinew; and how the Anishinaabe people of the Great Lakes region cultivated wild rice. We also learn how the Olmec people of San Lorenzo, Mexico combined latex from the rubber trees with sap from morning glory plants to create rubber; how the Anasazi of Colorado built “apartment buildings” of sandstone; and the Hohokam of Arizona constructed canals to irrigate corn and cotton crops.Interspersed with historical evidence realities gleaned from archeological sources, are myths that give a sense of the storytelling voice of each culture. In fact, the title of the book, “Turtle Island” is derived from the “Sky Woman” creation myth of the Haudenosaunee. For the most part, interspersing fact and story works well; however, on page 68 it becomes problematic. Here, an Aztec myth prophesying the arrival of “pale strangers with beards” is immediately followed—without a subheading or page break—by the sentence, “The Arctic is a place that tests anyone who lives there.” A six-page discussion of the Thule, Inuit, Tuniit, and Vikings ensues. Adults will grasp the connection of the Aztec prophecy to the arrival of the Vikings; children might—because of the juxtaposition of texts—associate the Aztecs themselves with the Arctic. Teacher or parent intervention here may be required.The book concludes with a discussion of laws, proclamations, wars, and institutions that affected Indigenous lives. Examples include: The Royal Proclamation of 1763 that declared British authority over the “Indian Territories;” the American War of Independence and the subsequent drive westward of settlers; the brutal slaughter at Wounded Knee; and, in both the U.S. and Canada, the residential schools.Apart from the one flaw mentioned above, the book is nicely designed, colourful, and clearly illustrated. Elementary school students should find it readable, enjoying its combination of myth and fact. In sum, Turtle Island is an excellent choice for both school and public libraries.Reviewer: Leslie AitkenHighly recommended: 4 out of 4 starsLeslie Aitken’s long career in librarianship involved selection of children’s literature for school, public, special, and university collections. She is a former Curriculum Librarian at the University of Alberta.

The Leichhardt Highway is a six hundred-kilometre stretch of sealed inland road that joins the Australian Queensland border town of Goondiwindi with the Capricorn Highway, just south of the Tropic of Capricorn. Named after the young Prussian naturalist Ludwig Leichhardt, part of this roadway follows the route his party took as they crossed northern Australia from Morton Bay (Brisbane) to Port Essington (near Darwin). Ignoring the usual colonial practice of honouring the powerful and aristocratic, Leichhardt named the noteworthy features along this route after his supporters and fellow expeditioners. Many of these names are still in use and a series of public monuments have also been erected in the intervening century and a half to commemorate this journey. Unlike Leichhardt, who survived his epic trip, some contemporary travellers who navigate the remote roadway named in his honour do not arrive at their final destinations. Memorials to these violently interrupted lives line the highway, many enigmatically located in places where there is no obvious explanation for the lethal violence that occurred there. This examination profiles the memorials along Leichhardt’s highway as Gothic practice, in order to illuminate some of the uncanny paradoxes around public memorials, as well as the loaded emotional terrain such commemorative practices may inhabit. All humans know that death awaits them (Morell). Yet, despite this, and the unprecedented torrent of images of death and dying saturating news, television, and social media (Duwe; Sumiala; Bisceglio), Gorer’s mid-century ideas about the denial of death and Becker’s 1973 Pulitzer prize-winning description of the purpose of human civilization as a defence against this knowledge remains current in the contemporary trope that individuals (at least in the West) deny their mortality. Contributing to this enigmatic situation is how many deny the realities of aging and bodily decay—the promise of the “life extension” industries (Hall)—and are shielded from death by hospitals, palliative care providers, and the multimillion dollar funeral industry (Kiernan). Drawing on Piatti-Farnell’s concept of popular culture artefacts as “haunted/haunting” texts, the below describes how memorials to the dead can powerfully reconnect those who experience them with death’s reality, by providing an “encrypted passageway through which the dead re-join the living in a responsive cycle of exchange and experience” (Piatti-Farnell). While certainly very different to the “sublime” iconic Gothic structure, the Gothic ruin that Summers argued could be seen as “a sacred relic, a memorial, a symbol of infinite sadness, of tenderest sensibility and regret” (407), these memorials do function in both this way as melancholy/regret-inducing relics as well as in Piatti-Farnell’s sense of bringing the dead into everyday consciousness. Such memorialising activity also evokes one of Spooner’s features of the Gothic, by acknowledging “the legacies of the past and its burdens on the present” (8).Ludwig Leichhardt and His HighwayWhen Leichhardt returned to Sydney in 1846 from his 18-month journey across northern Australia, he was greeted with surprise and then acclaim. Having mounted his expedition without any backing from influential figures in the colony, his party was presumed lost only weeks after its departure. Yet, once Leichhardt and almost all his expedition returned, he was hailed “Prince of Explorers” (Erdos). When awarding him a significant purse raised by public subscription, then Speaker of the Legislative Council voiced what he believed would be the explorer’s lasting memorial —the public memory of his achievement: “the undying glory of having your name enrolled amongst those of the great men whose genius and enterprise have impelled them to seek for fame in the prosecution of geographical science” (ctd. Leichhardt 539). Despite this acclaim, Leichhardt was a controversial figure in his day; his future prestige not enhanced by his Prussian/Germanic background or his disappearance two years later attempting to cross the continent. What troubled the colonial political class, however, was his transgressive act of naming features along his route after commoners rather than the colony’s aristocrats. Today, the Leichhardt Highway closely follows Leichhardt’s 1844-45 route for some 130 kilometres from Miles, north through Wandoan to Taroom. In the first weeks of his journey, Leichhardt named 16 features in this area: 6 of the more major of these after the men in his party—including the Aboriginal man ‘Charley’ and boy John Murphy—4 more after the tradesmen and other non-aristocratic sponsors of his venture, and the remainder either in memory of the journey’s quotidian events or natural features there found. What we now accept as traditional memorialising practice could in this case be termed as Gothic, in that it upset the rational, normal order of its day, and by honouring humble shopkeepers, blacksmiths and Indigenous individuals, revealed the “disturbance and ambivalence” (Botting 4) that underlay colonial class relations (Macintyre). On 1 December 1844, Leichhardt also memorialised his own past, referencing the Gothic in naming a watercourse The Creek of the Ruined Castles due to the “high sandstone rocks, fissured and broken like pillars and walls and the high gates of the ruined castles of Germany” (57). Leichhardt also disturbed and disfigured the nature he so admired, famously carving his initials deep into trees along his route—a number of which still exist, including the so-called Leichhardt Tree, a large coolibah in Taroom’s main street. Leichhardt also wrote his own memorial, keeping detailed records of his experiences—both good and more regretful—in the form of field books, notebooks and letters, with his major volume about this expedition published in London in 1847. Leichhardt’s journey has since been memorialised in various ways along the route. The Leichhardt Tree has been further defaced with numerous plaques nailed into its ancient bark, and the town’s federal government-funded Bicentennial project raised a formal memorial—a large sandstone slab laid with three bronze plaques—in the newly-named Ludwig Leichhardt Park. Leichhardt’s name also adorns many sites both along, and outside, the routes of his expeditions. While these fittingly include natural features such as the Leichhardt River in north-west Queensland (named in 1856 by Augustus Gregory who crossed it by searching for traces of the explorer’s ill-fated 1848 expedition), there are also many businesses across Queensland and the Northern Territory less appropriately carrying his name. More somber monuments to Leichhardt’s legacy also resulted from this journey. The first of these was the white settlement that followed his declaration that the countryside he moved through was well endowed with fertile soils. With squatters and settlers moving in and land taken up before Leichhardt had even arrived back in Sydney, the local Yeeman people were displaced, mistreated and completely eradicated within a decade (Elder). Mid-twentieth century, Patrick White’s literary reincarnation, Voss of the eponymous novel, and paintings by Sidney Nolan and Albert Tucker have enshrined in popular memory not only the difficult (and often described as Gothic) nature of the landscape through which Leichhardt travelled (Adams; Mollinson, and Bonham), but also the distinctive and contrary blend of intelligence, spiritual mysticism, recklessness, and stoicism Leichhardt brought to his task. Roadside Memorials Today, the Leichhardt Highway is also lined with a series of roadside shrines to those who have died much more recently. While, like centotaphs, tombstones, and cemeteries, these memorialise the dead, they differ in usually marking the exact location that death occurred. In 43 BC, Cicero articulated the idea of the dead living in memory, “The life of the dead consists in the recollection cherished of them by the living” (93), yet Nelson is one of very few contemporary writers to link roadside memorials to elements of Gothic sensibility. Such constructions can, however, be described as Gothic, in that they make the roadway unfamiliar by inscribing onto it the memory of corporeal trauma and, in the process, re-creating their locations as vivid sites of pain and suffering. These are also enigmatic sites. Traffic levels are generally low along the flat or gently undulating terrain and many of these memorials are located in locations where there is no obvious explanation for the violence that occurred there. They are loci of contradictions, in that they are both more private than other memorials, in being designed, and often made and erected, by family and friends of the deceased, and yet more public, visible to all who pass by (Campbell). Cemeteries are set apart from their surroundings; the roadside memorial is, in contrast, usually in open view along a thoroughfare. In further contrast to cemeteries, which contain many relatively standardised gravesites, individual roadside memorials encapsulate and express not only the vivid grief of family and friends but also—when they include vehicle wreckage or personal artefacts from the fatal incident—provide concrete evidence of the trauma that occurred. While the majority of individuals interned in cemeteries are long dead, roadside memorials mark relatively contemporary deaths, some so recent that there may still be tyre marks, debris and bloodstains marking the scene. In 2008, when I was regularly travelling this roadway, I documented, and researched, the six then extant memorial sites that marked the locations of ten fatalities from 1999 to 2006. (These were all still in place in mid-2014.) The fatal incidents are very diverse. While half involved trucks and/or road trains, at least three were single vehicle incidents, and the deceased ranged from 13 to 84 years of age. Excell argues that scholarship on roadside memorials should focus on “addressing the diversity of the material culture” (‘Contemporary Deathscapes’) and, in these terms, the Leichhardt Highway memorials vary from simple crosses to complex installations. All include crosses (mostly, but not exclusively, white), and almost all are inscribed with the name and birth/death dates of the deceased. Most include flowers or other plants (sometimes fresh but more often plastic), but sometimes also a range of relics from the crash and/or personal artefacts. These are, thus, unsettling sights, not least in the striking contrast they provide with the highway and surrounding road reserve. The specific location is a key component of their ability to re-sensitise viewers to the dangers of the route they are travelling. The first memorial travelling northwards, for instance, is situated at the very point at which the highway begins, some 18 kilometres from Goondiwindi. Two small white crosses decorated with plastic flowers are set poignantly close together. The inscriptions can also function as a means of mobilising connection with these dead strangers—a way of building Secomb’s “haunted community”, whereby community in the post-colonial age can only be built once past “murderous death” (131) is acknowledged. This memorial is inscribed with “Cec Hann 06 / A Good Bloke / A Good hoarseman [sic]” and “Pat Hann / A Good Woman” to tragically commemorate the deaths of an 84-year-old man and his 79-year-old wife from South Australia who died in the early afternoon of 5 June 2006 when their Ford Falcon, towing a caravan, pulled onto the highway and was hit by a prime mover pulling two trailers (Queensland Police, ‘Double Fatality’; Jones, and McColl). Further north along the highway are two memorials marking the most inexplicable of road deaths: the single vehicle fatality (Connolly, Cullen, and McTigue). Darren Ammenhauser, aged 29, is remembered with a single white cross with flowers and plaque attached to a post, inscribed hopefully, “Darren Ammenhauser 1971-2000 At Rest.” Further again, at Billa Billa Creek, a beautifully crafted metal cross attached to a fence is inscribed with the text, “Kenneth J. Forrester / RIP Jack / 21.10.25 – 27.4.05” marking the death of the 79-year-old driver whose vehicle veered off the highway to collide with a culvert on the creek. It was reported that the vehicle rolled over several times before coming to rest on its wheels and that Forrester was dead when the police arrived (Queensland Police, ‘Fatal Traffic Incident’). More complex memorials recollect both single and multiple deaths. One, set on both sides of the road, maps the physical trajectory of the fatal smash. This memorial comprises white crosses on both sides of road, attached to a tree on one side, and a number of ancillary sites including damaged tyres with crosses placed inside them on both sides of the road. Simple inscriptions relay the inability of such words to express real grief: “Gary (Gazza) Stevens / Sadly missed” and “Gary (Gazza) Stevens / Sadly missed / Forever in our hearts.” The oldest and most complex memorial on the route, commemorating the death of four individuals on 18 June 1999, is also situated on both sides of the road, marking the collision of two vehicles travelling in opposite directions. One memorial to a 62-year-old man comprises a cross with flowers, personal and automotive relics, and a plaque set inside a wooden fence and simply inscribed “John Henry Keenan / 23-11-1936–18-06-1999”. The second memorial contains three white crosses set side-by-side, together with flowers and relics, and reveals that members of three generations of the same family died at this location: “Raymond Campbell ‘Butch’ / 26-3-67–18-6-99” (32 years of age), “Lorraine Margaret Campbell ‘Lloydie’ / 29-11-46–18-6-99” (53 years), and “Raymond Jon Campbell RJ / 28-1-86–18-6-99” (13 years). The final memorial on this stretch of highway is dedicated to Jason John Zupp of Toowoomba who died two weeks before Christmas 2005. This consists of a white cross, decorated with flowers and inscribed: “Jason John Zupp / Loved & missed by all”—a phrase echoed in his newspaper obituary. The police media statement noted that, “at 11.24pm a prime mover carrying four empty trailers [stacked two high] has rolled on the Leichhardt Highway 17km north of Taroom” (Queensland Police, ‘Fatal Truck Accident’). The roadside memorial was placed alongside a ditch on a straight stretch of road where the body was found. The coroner’s report adds the following chilling information: “Mr Zupp was thrown out of the cabin and his body was found near the cabin. There is no evidence whatsoever that he had applied the brakes or in any way tried to prevent the crash … Jason was not wearing his seatbelt” (Cornack 5, 6). Cornack also remarked the truck was over length, the brakes had not been properly adjusted, and the trip that Zupp had undertaken could not been lawfully completed according to fatigue management regulations then in place (8). Although poignant and highly visible due to these memorials, these deaths form a small part of Australia’s road toll, and underscore our ambivalent relationship with the automobile, where road death is accepted as a necessary side-effect of the freedom of movement the technology offers (Ladd). These memorials thus animate highways as Gothic landscapes due to the “multifaceted” (Haider 56) nature of the fear, terror and horror their acknowledgement can bring. Since 1981, there have been, for instance, between some 1,600 and 3,300 road deaths each year in Australia and, while there is evidence of a long term downward trend, the number of deaths per annum has not changed markedly since 1991 (DITRDLG 1, 2), and has risen in some years since then. The U.S.A. marked its millionth road death in 1951 (Ladd) along the way to over 3,000,000 during the 20th century (Advocates). These deaths are far reaching, with U.K. research suggesting that each death there leaves an average of 6 people significantly affected, and that there are some 10 to 20 per cent of mourners who experience more complicated grief and longer term negative affects during this difficult time (‘Pathways Through Grief’). As the placing of roadside memorials has become a common occurrence the world over (Klaassens, Groote, and Vanclay; Grider; Cohen), these are now considered, in MacConville’s opinion, not only “an appropriate, but also an expected response to tragedy”. Hockey and Draper have explored the therapeutic value of the maintenance of “‘continuing bonds’ between the living and the dead” (3). This is, however, only one explanation for the reasons that individuals erect roadside memorials with research suggesting roadside memorials perform two main purposes in their linking of the past with the present—as not only sites of grieving and remembrance, but also of warning (Hartig, and Dunn; Everett; Excell, Roadside Memorials; MacConville). Clark adds that by “localis[ing] and personalis[ing] the road dead,” roadside memorials raise the profile of road trauma by connecting the emotionless statistics of road death directly to individual tragedy. They, thus, transform the highway into not only into a site of past horror, but one in which pain and terror could still happen, and happen at any moment. Despite their increasing commonality and their recognition as cultural artefacts, these memorials thus occupy “an uncomfortable place” both in terms of public policy and for some individuals (Lowe). While in some states of the U.S.A. and in Ireland the erection of such memorials is facilitated by local authorities as components of road safety campaigns, in the U.K. there appears to be “a growing official opposition to the erection of memorials” (MacConville). Criticism has focused on the dangers (of distraction and obstruction) these structures pose to passing traffic and pedestrians, while others protest their erection on aesthetic grounds and even claim memorials can lower property values (Everett). While many ascertain a sense of hope and purpose in the physical act of creating such shrines (see, for instance, Grider; Davies), they form an uncanny presence along the highway and can provide dangerous psychological territory for the viewer (Brien). Alongside the townships, tourist sites, motels, and petrol stations vying to attract customers, they stain the roadway with the unmistakable sign that a violent death has happened—bringing death, and the dead, to the fore as a component of these journeys, and destabilising prominent cultural narratives of technological progress and safety (Richter, Barach, Ben-Michael, and Berman).Conclusion This investigation has followed Goddu who proposes that a Gothic text “registers its culture’s contradictions” (3) and, in profiling these memorials as “intimately connected to the culture that produces them” (Goddu 3) has proposed memorials as Gothic artefacts that can both disturb and reveal. Roadside memorials are, indeed, so loaded with emotional content that their close contemplation can be traumatising (Brien), yet they are inescapable while navigating the roadway. Part of their power resides in their ability to re-animate those persons killed in these violent in the minds of those viewing these memorials. In this way, these individuals are reincarnated as ghostly presences along the highway, forming channels via which the traveller can not only make human contact with the dead, but also come to recognise and ponder their own sense of mortality. While roadside memorials are thus like civic war memorials in bringing untimely death to the forefront of public view, roadside memorials provide a much more raw expression of the chaotic, anarchic and traumatic moment that separates the world of the living from that of the dead. While traditional memorials—such as those dedicated by, and to, Leichhardt—moreover, pay homage to the vitality of the lives of those they commemorate, roadside memorials not only acknowledge the alarming circumstances of unexpected death but also stand testament to the power of the paradox of the incontrovertibility of sudden death versus our lack of ability to postpone it. In this way, further research into these and other examples of Gothic memorialising practice has much to offer various areas of cultural study in Australia.ReferencesAdams, Brian. Sidney Nolan: Such Is Life. Hawthorn, Vic.: Hutchinson, 1987. Advocates for Highway and Auto Safety. “Motor Vehicle Traffic Fatalities & Fatality Rate: 1899-2003.” 2004. Becker, Ernest. The Denial of Death. New York: Simon & Schuster, 1973. Bisceglio, Paul. “How Social Media Is Changing the Way We Approach Death.” The Atlantic 20 Aug. 2013. Botting, Fred. Gothic: The New Critical Idiom. 2nd edition. Abingdon, UK: Routledge, 2014. 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