Porous Limestone Research Articles

Pore size distribution and the durability of a porous limestone

Abstract A comparison of durability estimations based on mercury porosimeter data and experimental salt crystallization tests carried out on Bateig Stone from Alicante, Spain, establish that the main factor in the salt crystallization durability test is the ‘ink bottle’ pore system, identified by the presence of residual mercury in large pores after porosity testing. In addition, the results suggest that the commonly used indirect durability tests may not be considered a scientific definition of building stone behaviour.

The Development of the Eocene Platform Carbonates from Wells in the Middle Adriatic Off-Shore Area, Croatia

In the Middle Adriatic deep off-shore wells the following sedimentary faciess exist: fenestral and Charophyte limestone facies (X); facies of foraminiferal wackestone-packstone, ostracod marls and fine grained breccia conglomerate (A): facies of foraminiferal packstonegrainstone (B) and miliolidal mudstone-wackestone (C): facies of porous limestone?, grainstone? (Y): facies of fossiliferous mudstonepackstone (D); algal bound stone/bindstone and wackestone facies (E): facies of the foraminiferal mudstone-packstone (F); Nummulites - Discocyclina floatstone-packstone and grainstone-rudstone facies (G). The sediments were deposited close to the carbonate platform margin. Beds of facies X have an uncertain stratigraphic position; younger than the Cretaceous but older than the Cuisian. A transgressive sequence that is composed of facies A, B, C and Y was formed during the Cuisian, whereas the others belong to Lutetian (and Biarritzian). At the end of the Middle Eocene they were tectonically compressed and covered by flysch deposits. Good stratigraphic correlation between the wells along the Dinaric strike strongly suggests that the facics are laterally extensive in this direction. Perpendicular to the trend they arc considerably reduced. Oil shows in the Kate- I well originated from the Lower Cretaceous so surce rocks (evaporite complex).

Evidence for groundwater and surface marine water contamination by waste disposal wells in the Florida keys

One of the methods for domestic wastewater disposal in the Florida Keys is injection of partially treated wastewater into the highly porous limestone bedrock using waste disposal or injection wells. In an effort to understand the transport and fate of wastewater, we utilized bacteriophages as tracers in a 12.2-m deep, simulated injection well in Key Largo and an active (27.4 m deep) class V disposal well in the Middle Keys. The latter is the currently permitted type of injection well used for multi-unit domestic waste disposal in the Keys. Surface waters and groundwater at several sites were monitored for 5 days after seeding of the injection wells. In both environments, viral tracers appeared after short periods of time in groundwater (8 h after injection) and surface marine waters (10 h and 53 h for Key Largo and the Middle Keys, respectively). Estimated rates of tracer movement were greatest in Key Largo (2.5–35 m/h), where tidal pumping was implicated in tracer movement. In the Middle Keys, the pattern of movement showed little evidence of tidal pumping, and migration rates were slower (0.12–2 m/h). Collectively these results indicate that wastewater injected into the subsurface can make its way rapidly to surface marine waters, where it may contribute to water quality deterioration.

Infant mortality and soil type: a case study in south‐central England (with discussion)

SummaryWe have analysed the differences in infant mortality for 1981 to 1990 in areas of contrasting soil types in south‐central England. The soils overlie rocks of varied lithology and hydrology, ranging from porous and permeable Chalk and limestones, to the generally wet and impermeable Oxford and Lower Jurassic Clays. The study area comprises 504 administrative wards, for each of which the soil has been classified as being predominantly‘Wet’, ‘ Intermediate’ or ‘Dry’, depending on the degree of seasonal or periodic waterlogging. The soil classes used are those mapped by the Soil Survey of England and Wales and relate closely to the underlying geology. We find proportionately more infant deaths on the‘Wet’ soils, and a gradation towards lower infant mortality rates on the drier soils. Overall, infant mortality on the‘Wet’ soils is 31·9 percent greater than on the‘Dry’ soils, for reasons that remain unexplained. This relation between infant mortality and soil moisture remains after the effect of social class has been removed.

Edale no. 1 oilwell, Derbyshire, UK, 1938

In New Year 1938, the Edale No. 1 oilwell was drilled in the English Pennines. The target for the well was folded Lower Carboniferous limestone. This target was believed to be analogous both for trap and reservoir, to the giant oil accumulations of Iran (then Persia). The well failed. Poor gas shows were recorded at a depth of 126feet. This gas flowed at a rate of 4000ft 3 day −1. There were also minor indications of brown and green oil but no commercial production. Trap and seal were proven. Local seepage also proved the existence of a working source. Reservoirwas however missing. The well was drilled outwith the play fairway. Instead of penetrating massive, porous shelf limestones the well encountered thin shaley limestones, today interpreted as deep water, gravity flow deposits. This paper recounts the geological work done before and during drilling of the well. The data, in the form of a prospect evaluation memorandum, are from the BP Exploration archive.

TECTONIC CONTROLS ON THE EVOLUTION OF POROSITY IN THE CRETACEOUS MARDIN GROUP CARBONATES, ADIYAMAN OILFIELDS, SE TURKEY

The mid‐Cretaceous Mardin Group carbonates constitute the principal reservoir in a number of oilfields near the city of Adiyaman in SE Turkey (the Adiyaman, G. Adiyaman, Cemberlitas, Cukurtas, Bolukyayla and Karakus oilfields). Porosity development in these carbonates was controlled by two phases of brittle deformation. The first of these accompanied the emplacement of the allochthonous Koçali‐Karadut Complex in the Late Cretaceous (Maastrichtian), which principally influenced the development of porosity in the northern oilfields. Subsequently, movement during the Mio‐Pliocene on the transcurrent Adiyaman fault affected porosity development in the south.The topmost unit of the Mardin Group, the Karababa Formation, consists of argillaceous carbonates, whose permeability and porosity were increased as a result of abundant tectonically‐induced microfractures and stylolites. The underlying Derdere Formation includes porous limestones and dolomites, which are the principal reservoir units in the Adiyaman fields.Porosity versus depth and geothermal gradient versus depth curves indicate that porosity trends are controlled principally by the transcurrent Adiyaman fault and its antithetics. The Koçali‐Karadut thrusts have had less influence on the evolution of porosity in the Mardin Group carbonates in the study area.

Drying of a white porous limestone monitored by NMR imaging

Staining of porous limestone is a frequent problem observed when this kind of stone is used as floor pavement. From a chemical point of view, this staining originates from a reaction between alkalies (NaOH and KOH) released by the fresh mortar and absorbed by the stone and the organic elements always present in this kind of stone. Up to now, no other explanation of this phenomena has been given. CSTC and UCL showed that, in addition of the chemical potentiality characterised by the organics content of the stone, another factor had to be taken into account: the drying process of the material. A French limestone (Tercé Sculpture) sample has been saturated by capillarity, and its drying has been monitored by NMR imaging. NMR results were compared with the weight loss curve. The results have clearly shown the existence of two different stages in the drying process. The first stage corresponds to a constant drying rate period, and the second is characterised by a falling drying rate. NMR measurements led us to a better understanding of the physical meaning of these two stages. During the first one, evaporation occurs on the external faces of the sample. During the second one, evaporation occurs inside the sample. We concluded that the physical key factor in the problem of staining was the amount of water evaporated during the first stage of drying.

Coarse Aggregate Effects on Elastic Moduli of Concrete

The results of a laboratory testing program carried out to investigate the effect of coarse aggregate types on the elastic modulus of typical pavement concretes are presented. The elastic modulus was determined in both flexure and compression using static and dynamic means. Three different mixes, made using three different aggregates, were compared. The water-cement ratio was kept at 0.53 throughout the test program. The results showed that within the tested range, the aggregate type significantly affected the studied properties of concrete. Calera aggregate (a dense limestone) with its rough-textured surface and angular shape produced a concrete with higher strength and stiffness than those of concretes made with Brooksville aggregate (a porous limestone) and river gravel. In addition, the measured dynamic modulus in compression was significantly different from that in flexure. Also, in flexure, the dynamic modulus was higher than the static modulus by an average of 23 percent, whereas in compression, th...

Coarse Aggregate Effects on Elastic Moduli of Concrete

The results of a laboratory testing program carried out to investigate the effect of coarse aggregate types on the elastic modulus of typical pavement concretes are presented. The elastic modulus was determined in both flexure and compression using static and dynamic means. Three different mixes, made using three different aggregates, were compared. The water-cement ratio was kept at 0.53 throughout the test program. The results showed that within the tested range, the aggregate type significantly affected the studied properties of concrete. Calera aggregate (a dense limestone) with its rough-textured surface and angular shape produced a concrete with higher strength and stiffness than those of concretes made with Brooksville aggregate (a porous limestone) and river gravel. In addition, the measured dynamic modulus in compression was significantly different from that in flexure. Also, in flexure, the dynamic modulus was higher than the static modulus by an average of 23 percent, whereas in compression, the dynamic modulus appeared to be in the same range as the static modulus. The change in frequency from 1 to 7 Hz did not have a significant influence on the dynamic modulus.

Modeling Damage to Limestone Exposed to Atmospheric Pollutants

ABSTRACTPreservation of building and monument stone exposed to acidic environments relies on the understanding of acidic precipitation deposition processes and damage mechanisms. Presented here is a model which predicts sulfur accumulation in porous limestone subjected to dry deposition of SO2. The model assumes deposition and reaction of SO2 to form a thin gypsum crust on the moist surface of the stone, and subsequent sulfur (as aqueous sulfate) transport and accumulation in the stone interior driven by diurnal wetting and drying of the stone surface. Characterization of the limestone pore structure contributes significantly to the evaluation and interpretation of modeled sulfate transport and accumulation in porous building materials. Predicted sulfur accumulation in the stone interior is dependent on the surface boundary conditions, the stone pore geometry and structure, and the rates and mechanisms of aqueous/solid sulfur partitioning (i.e. adsorption, precipitation and dissolution). Model results are compared to moisture content and sulfur accumulation measured in limestone briquettes exposed to a natural dry deposition environment. The model successfully predicts moisture transport in field-exposed limestone, but overestimates the rate of sulfur accumulation. The model may be improved by quantification of the time dependence of the surface sulfate concentration and better understanding of the sulfate partitioning mechanisms.

Strength, Water Absorption and Porosity of Concrete Incorporating Natural and Crushed Aggregate

This paper presents the results of an extensive experimental program which was carried out to study the influence of Riyadh area aggregates on the compressive strength, water absorption, and porosity of the concrete. Parameters involved were crushed washed aggregate, natural unwashed aggregate, and four different water cement ratios.Natural aggregates are characterized as porous limestone rocks with high water absorption, low bulk specific gravity, excessively dusty degraded, and contain large quantities of very fine sand.Test results indicate that with proper selection of mix proportions and adequate compaction both aggregates can be used to produce concrete with ultimate compressive strength that is usually specified for most concrete structural applications. Results also indicate that the natural aggregate concrete has less compressive strength, less porosity and higher water absorption compared to that of concrete made with crushed aggregate. This is true for 0.4, 0.45, 0.5, and 0.55 water cement ratios.

Viral tracer studies indicate contamination of marine waters by sewage disposal practices in key largo, Florida

Domestic wastewater disposal practices in the Florida Keys are primarily limited to on-site disposal systems such as septic tanks, injection wells, and illegal cesspits. Poorly treated sewage is thus released into the highly porous subsurface Key Largo limestone matrix. To investigate the fate and transport of sewage in the subsurface environment and the potential for contamination of marine surface waters, we employed bacteriophages as tracers in a domestic septic system and a simulated injection well in Key Largo, Florida. Transport of bacteriophage (Phi)HSIC-1 from the septic tank to adjacent surface canal waters and outstanding marine waters occurred in as little as 11 and 23 h, respectively. Transport of the Salmonella phage PRD1 from the simulated injection well to a canal adjacent to the injection site occurred in 11.2 h. Estimated rates of migration of viral tracers ranged from 0.57 to 24.2 m/h, over 500-fold greater than flow rates measured previously by subsurface flow meters in similar environments. These results suggest that current on-site disposal practices can lead to contamination of the subsurface and surface marine waters in the Keys.

Occurrence of fecal indicator bacteria in surface waters and the subsurface aquifer in Key Largo, Florida

Sewage waste disposal facilities in the Florida Keys include septic tanks and individual package plants in place of municipal collection facilities in most locations. In Key Largo, both facilities discharge into the extremely porous Key Largo limestone. To determine whether there was potential contamination of the subsurface aquifer and nearby coastal surface waters by such waste disposal practices, we examined the presence of microbial indicators commonly found in sewage (fecal coliforms, Clostridium perfringens, and enterococci) and aquatic microbial parameters (viral direct counts, bacterial direct counts, chlorophyll a, and marine vibriophage) in injection well effluent, monitoring wells that followed a transect from onshore to offshore, and surface waters above these wells in two separate locations in Key Largo in August 1993 and March 1994. Effluent and waters from onshore shallow monitoring wells (1.8- to 3.7-m depth) contained two or all three of the fecal indicators in all three samples taken, whereas deeper wells (10.7- to 12.2-m depth) at these same sites contained few or none. The presence of fecal indicators was found in two of five nearshore wells (i.e., those that were < or = 1.8 miles [< or = 2.9 km] from shore), whereas offshore wells (> or = 2.1 to 5.7 miles [< or = 3.4 to 9.2 km] from shore) showed little sign of contamination. Indicators were also found in surface waters in a canal in Key Largo and in offshore surface waters in March but not in August. Collectively, these results suggest that fecal contamination of the shallow onshore aquifer, parts of the nearshore aquifer, and certain surface waters has occurred.(ABSTRACT TRUNCATED AT 250 WORDS)

A preliminary account of endolithic algae of limestone cliffs of the Niagara Escarpment

This paper reports the discovery of endolithic algae from vertical limestone cliffs associated with the Niagara Escarpment, southern Ontario, Canada. The endolithic habitat forms a distinctive dark green layer 1–3 mm below the surface of the porous dolomitic limestone. Samples of the algal layer were isolated from freshly cleaved rock samples using sterile probes and grown on a solid (agarized) standard algal mineral medium supplemented with soil extract. A diverse assemblage of organisms grew on the agar plates, including bacteria, fungi, blue-green algae (cyanobacteria), green algae, yellow-green algae, and occasionally the protonemata of mosses. Isolated algae belong to unicellular, colonial, and filamentous morphological types. Algal genera that have been identified include seven blue-green algae (Cyanophyta or Cyanobacteria), six green algae (Chlorophyta), and one yellow-green alga (Xanthophyceae). Six of the algal genera found in Ontario rocks also occur inside rocks of the Colorado plateau in northern Arizona, and one genus also occurs inside Antarctic rocks. Key words: terrestrial algae, endolithic organisms, limestone cliffs, Niagara Escarpment, southern Ontario.

Catalytic reduction of nitric oxide by carbon monoxide over calcined limestone: reversible deactivation in the presence of carbon dioxide

The influence of carbon dioxide on nitric oxide reduction by carbon monoxide catalyzed over a porous limestone Stevns Chalk was studied in a fixed bed quartz reactor at 850°C under alternating oxidizing and reducing conditions, and under constant reducing conditions. The presence of carbon dioxide was found to inhibit the catalytic nitric oxide reduction. The nitric oxide reduction by carbon monoxide was found to fit the power law expression − r NO = k · [NO] 1 · [CO] (0.8 – 0.9) · [CO 2] −0.7 at ambient pressures, for 300–1200 ppmv NO, 2–6 vol.-% CO and 2–16 vol.-% CO 2. A simple mechanism for the nitric oxide reduction is proposed and a rate expression which agrees with the experimental results is derived. This study indicates that investigations of nitric oxide reduction by carbon monoxide catalyzed by CaO should be carried out in the presence of relevant concentrations of carbon dioxide.

NMR Surface Relaxivity of Calcite with Adsorbed Mn2+

Calcite particles were exposed to Mn2+ in aqueous solution to allow adsorption. The calcite particles were then packed, and the NMR longitudinal relaxation time T1 of water saturating the interparticle pores was measured. NMR surface relaxivity was then computed as 1/(T1 · Sp/Vp), where Sp/Vp is the ratio of surface area to pore volume. Adsorbed manganese increases the NMR surface relaxivity to approximately 2.4 × 10-3 cm/s, roughly 50 times the surface relaxivity of very pure calcite. Flowing water with 4 μM Mn2+ through a porous limestone plug decreased its T1 by a factor of 6. Iron as adsorbate produced relatively small increases in surface relaxivity. These results suggest that manganese dominates the surface relaxivity of limestone rocks in situ, which is important in the interpretation of NMR borehole logs. Observations suggest that some adsorbed manganese eventually becomes buried by freshly precipitated calcite. In particular, the surface relaxivity increased with initial adsorption, but gradually decreased at long reaction times, even as the aqueous manganese concentration continued to decrease. NMR evidently senses only the manganese in the outermost atomic layer, and thus might prove useful in more detailed studies of adsorption.

23Na microimaging of water phase in porous limestone

23Na microimaging has been investigated as a method for discriminating multiple fluid phases in porous media. Useful23 Na images from NaCl saturated brine in limestone were obtained in a few-minutes. Good images requires several hours.

Can Regional Porosity Occurrence in Carbonate Slope and Basin Facies Systems be Predicted?: ABSTRACT

Subsurface carbonate depositional sequences (i.e., coeval platform-to-basin facies mosaics), which can most readily be identified by application of seismic sequence analysis, include porous units of complex geometry and occurrence. A highly sought-after occurrence of reservoir-grade porosity commonly, but not always, is associated with sequence boundaries. Therefore, porosity can be predicted to possible occur in already-lithified platform strata beneath significant unconformities of regional extent (e.g., cavernous porosity). By this method, however, the possible existence of porosity in carbonate slope and basin deposits may be overlooked because they do not lie beneath sequence-bounding unconformities insofar as they are not usually exposed subaerially during platform emergence. Yet, such facies compose locally significant hydrocarbon reservoirs in the Permian basin by virtue of high porosities and permeabilities and water-free production histories. Short of drilling or seismic wavelet analysis, can porosity in such facies be predicted a priori Reservoirs in carbonate slope and basin deposits in the Midland basin include both porous limestones and dolomites. Petrographic and geochemical studies indicate that syndepositional and shallow-burial diagenesis of such deposits mainly involved porosity reduction via calcite cementation, dolomitization, and compaction. Most of the porosity present in reservoirs in these facies was created by later dissolution in the deep-burialmore » environment as a consequence of rock interaction with connate fluids enriched in carbonic and sulfuric acid and/or organic acids generated during hydrocarbon maturation. These fluids migrated up and out from deeper parts of the basin through slope and basin deposits and into platform carbonate strata. Insofar as fluid migration pathways can be mapped or at least inferred by various means, it follows that porosity created (or destroyed) by these fluids also can be mapped predictively.« less

Numerical Models of Fluid Flow in Carbonate Platforms: Implications for Dolomitization

ABSTRACT The role of fluid flow in dolomitization is evaluated through hydrologic simulations designed to capture and test numerically the essential elements of some common dolomitization models. A two-dimensional, finite-difference code (Bethke 1985) was used to simulate single-phase flow of variable-salinity fluids driven by compaction, convection, and topography in carbonate platforms and adjacent basinal sediments. A simple hydrostratigraphic model consisting of a platform-reef complex surrounded by basin-filling shale was constructed to examine the magnitude and direction of compaction flow during the initial phase of subsidence. Most pore fluids in the shale migrate to the surface at velocities less than 0.1 mm/yr and basin-derived fluids are focused into the reef from only a limited distance of 10 km. Relatively porous and permeable basinal limestones and sandstones may act as conduits for updip fluid flow into the platform-reef complex. Magnesium mass-balance constraints coupled with hydrologic simulations suggest that burial compaction is not an efficient mechanism for regional dolomitization. Two-layer hydrostratigraphic models involving variable-salinity fluids show that evaporation of seawater results in downward and seaward fluid migration; the magnitude of flow is a function of fluid density. Even fluids at salinities marginally elevated above normal seawater values are capable of penetration several hundreds of meters into the underlying sediments, albeit at rates of less than 1 cm/yr. Paleohydrologic simulations coupled with thermodynamic arguments support that reflux of surface-derived waters evaporated past gypsum saturation is a viable dolomitization mechanism. Calculations utilizing rates of Mg mass flux show that dolomitization of large carbonate platforms (>10 km3) by fluids below halite saturation requires millions of years of reflux-driven flow. /P> Thermal convection of seawater through carbonate platforms has been simulated by varying the basal heat flow. The thermal pump produces a convection cell in which lateral and vertical flow achieve rates of 75.0 and 13.0 mm/yr. respectively. The potential for dolomitization is high because a large reservoir of Mg (seawater) is tapped, elevated temperatures drive fluids further into the stability field for dolomite, and kinetic inhibition of dolomite nucleation and growth is decreased. Simulations of high-frequency glacio-eustatic sea-level oscillations suggest that a dynamic hydrologic regime may be established. A sea-level fall of 2 m lasting for 10,000 yr can drive lateral flow at rates up to 0.15 m/yr. Dolomitization is possible because marine waters migrate through the carbonate platform in response to gradients of hydraulic head created by eustatic sea-level fluctuations.

Strength, deformation, and fluid flow measurements on joints in porous limestone : Proc Conference on Fractured and Jointed Rock Masses, Lake Tahoe, 3–5 June 1992 P349–357. Publ California: Lawrence Berkeley Laboratory, 1992

Strength, deformation, and fluid flow measurements on joints in porous limestone : Proc Conference on Fractured and Jointed Rock Masses, Lake Tahoe, 3–5 June 1992 P349–357. Publ California: Lawrence Berkeley Laboratory, 1992