Top PDF Evaluation of the Organic Carbon Content in the Low-Permeability Shale Formations (As in the Case of the Khadum Suite in the Ciscaucasia Region)

Evaluation of the Organic Carbon Content in the Low-Permeability Shale Formations (As in the Case of the Khadum Suite in the Ciscaucasia Region)

Evaluation of the Organic Carbon Content in the Low-Permeability Shale Formations (As in the Case of the Khadum Suite in the Ciscaucasia Region)

The objective of the study is to evaluate the initial content of organic carbon, which is lost in the hydrocarbon generation and catagenesis. It is required for the reliable evaluation of source rock generation potential. The greater the differences between the contemporary and initial values of organic carbon, the greater the maturity of the source rock. Due to the catagenetic consumption of organic substance for the formation of hydrocarbons and non-hydrocarbon products, there is a reduction in the mass of organic substance during the catagenesis, and at every stage of transformation we deal with the residual concentrations. To restore the original values of organic carbon by the beginning of catagenesis, i.e. by the beginning of HC generation, we recommend using the conversion factors that take into account both the type and concentration of substance, as well as the catagenesis gradations, reached by the oil source deposits. As a result of calculations, it was determined that the original concentrations of organic carbon in Bajocian-Bathian clays is 2.7- 3.12%, in the Aptian-Albian deposits – 3.9 to 4.4%, in the deposits of the Khadum suite – 3-5.5%. Due to that, the average hydrocarbon potential was increased 1.5-2 times. Based on the results of initial source rock state recovery, we have made a map of initial organic carbon content that allows us to give a reliable estimate of generation potential for the source rocks of the Khadum suite, and to determine the perspectives of hydrocarbon accumulations exploration in the low-permeability shale formations of Ciscaucasia.
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Petrophysical evaluation of Total Organic Carbon Content (TOC) in Agbada Formation, Niger Delta Basin

Petrophysical evaluation of Total Organic Carbon Content (TOC) in Agbada Formation, Niger Delta Basin

Total Organic Carbon (TOC) content which is crucial for source rock evaluation was analysed in the Agbada Formation based on density log method. Four organic-rich horizons delineated across six GABO wells in the Niger Delta showed average TOC values of 6.38wt% for horizon 1, 6.97wt% for horizon 2, 6.41wt% for horizon 3 and 5.67wt% for horizon 4. These values are above the standard minimum threshold value of source rock for hydrocarbon generation in the Niger Delta which is 0.5wt%. The values are also greater than 2wt%, and thus in rating, they are classified as excellent source rocks. The implication is that the organic-rich sediments (shale units) of the Agbada Formation are good source rocks and contribute to hydrocarbon generation in the Niger Delta basin.
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Total and labile organic carbon content in agroecological system

Total and labile organic carbon content in agroecological system

Evaluation of MBC was made from fumigation- extraction method, modified by De-Polli & Guerra (2008), when LCNF and LCF were used for MBC estimative. Additionally, in recent researches LCNF and LCF was been used as new method to evaluate soil quality (DE-POLLI et al., 2007). Fumigation was performed by direct adding of 1 mL of ethanol-free chloroform at each soil sample of 20g in 100mL tubes kept closed and in darkness during 24 hours and then opened inside an exhaustion hood and left for one hour in order to evaporate chloroform (BROOKES et al., 1982; WITT et al., 2000). Subsamples were taken (three for fumigation and three kept without fumigation) of 20g of soil (humid base) that received 50 mL of K 2 SO 4 0.5 mol L -1 , and were agitated during 30 minutes and left for decantation for more 30 minutes, filtrated in medium filtration paper for separation of 8mL aliquot of the extract; added with 2 mL of K 2 Cr 2 O 7 0.066 mol L -1 ; 10 mL of H 2 SO 4 PA and 1 mL of H 3 PO 4 , cooled; completed with distilled water and titrated with ferrous ammonium sulfate 0.038N.
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Evaluation of Volatile and Semi-Volatile Organic Compounds Potentially Associated with the Gas Shale Fracturing Process in the Fayetteville and Marcellus Shale

Evaluation of Volatile and Semi-Volatile Organic Compounds Potentially Associated with the Gas Shale Fracturing Process in the Fayetteville and Marcellus Shale

In order to develop these shale gas reserves, a process known as hydraulic fracturing is utilized. Hydraulic fracturing is a process used in the extraction of underground resources to increase oil, natural gas and, water production rates when these resources are located in rock formations with a naturally low permeability (King, 2012). During the hydraulic fracturing process, water is injected at high pressures to increase pore pressure. As the pore pressure is increased the total normal stress is reduced causing a reduction in the formations shear strength (Davies et al., 2013). The reduction in shear strength leads to a fracture event. As more fractures develop, the permeability of the formation increases allowing for increased production rates (Davies et al., 2013). Hydraulic fracturing can be broken down into two methods, vertical fracturing and horizontal fracturing. After the fracturing event is complete, injection waters return to the surface as flowback water (Hayes, 2009). This flowback period lasts for the first 14 days (Hayes, 2009). After is point the composition of the waters changes to produced waters. Produced waters are waters that occur naturally in the rock formation (Hayes, 2009).
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Total Organic Carbon Variability in The Utica Shale of Northwest Ohio

Total Organic Carbon Variability in The Utica Shale of Northwest Ohio

1 Introduction Shale Reservoirs: As energy demands increase, oil and gas companies are looking to exploit unconventional reservoirs to produce hydrocarbons. Shales rich in organic content are one of these unconventional reservoirs. Shale reservoirs are considered unconventional because their low permeability makes it very difficult produce hydrocarbons from them, but new techniques such as hydraulic fracturing and horizontal drilling have made it possible to extract economic amounts of oil and gas from them. Many different reservoir

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Chemical Structure of Kerogen of Shale Formations. (By the Example of the Shale Formations of the East European Platform)

Chemical Structure of Kerogen of Shale Formations. (By the Example of the Shale Formations of the East European Platform)

In terms of the composition of hydrocarbon components of bitumoid and products of desulfurization of its polar fraction, the main bio-producers that contributed to the composition of OM of Jurassic deposits are marine phytoplankton and, to a lesser extent, Embryophytes. One of the main differences in the composition of pyrolysis products of kerogens isolated from rocks comprising various concentrations of total organic carbon (TOC) is the increasing proportion of thiophenic structures as TOC increases. The presence of low-molecular or short-chain alkyl-substituted thiophenes with a linear carbon skeleton in pyrolysis products is due to the involvement of carbohydrate components of the starting organic matter in the processes of sulfur bonding in the stages of sedimentogenesis and diagenesis. Sulfurization of carbohydrates resulted in the formation of a poly-sulfur-bound structure that is part of kerogen, which, when pyrolyzed, yields thiophenes of similar structure. There was an increase in the content of long-chain n-alkylthiophenes in the higher-molecular fraction.
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The Flow Regimes Associated with Hydraulic Fractured Horizontal Wells in Shale Formations

The Flow Regimes Associated with Hydraulic Fractured Horizontal Wells in Shale Formations

24 4.3. Step 3. Sensitivity Analysis 4.3.1. Scenario1 The base model with no desorption for the model with 1, 2, and 4 hydraulic fractures were run with 250 feet half-length size for hydraulic fractures with 0.002 mD fissure permeability. Figure 17 illustrates this case study for the model with 4 hydraulic fractures vs. its original case study to show the differences in flow regimes. By decreasing the size of fracture half-length to 250 feet, the early linear flow becomes longer compare to the 500 feet case and same condition for compounded linear flow but for the case with one hydraulic fracture, the early linear flow ends sooner and compounded linear flow has longer duration compare to its original case and same condition for the model with 2 hydraulic fractures. Table 12 demonstrations the flow durations for current scenario. Other diagnostic plots for the models are included in appendices too.
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Resolving issues of content uniformity and low permeability using eutectic blend of camphor and menthol

Resolving issues of content uniformity and low permeability using eutectic blend of camphor and menthol

The powder blend of batch B9, equivalent to one dose of captopril (167 mg), was filled in capsule (batch B10). Batch B11 was obtained by compressing 167 mg of powder blend of batch B9. The diameter and thickness of the tablet were 7.87 and 3.15 mm respectively. The crushing strength and friability of the tablet were 9±0.4 kp and 0.42%. Sodium starch glycolate and Avicel PH 102 contributed to fast disintegration (6.5 min). The moisture content in batch B9 was 1.2%. The volume of eutectic liquid formed on mixing 5 g each of camphor and menthol was 8 ml. The maximum permissible dose of camphor is 30
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Improving the Total Organic Carbon Estimation of the Eagle Ford Shale with Density Logs by Considering the Effect of Pyrite

Improving the Total Organic Carbon Estimation of the Eagle Ford Shale with Density Logs by Considering the Effect of Pyrite

often changed from one region to the next. Fertl [ 4 , 5 ] summarized the potassium, thorium, and uranium distributions in shales, suggesting correlations between these elements and elemental ratios (U, Th, K, and Th/U), and organic richness. This approach is also valuable, but has to be calibrated for the region of interest. Estimating TOC with density logs is another well-accepted method [ 7 – 11 ]. Equations, including bulk density, have been derived in building petrophysical models containing different components of the shale formation. For example, Schmoker [ 7 , 8 ] estimated the organic carbon of the Bakken Formation, based on density data, with a four-component shale system assumption. Alfred and Vernik [ 11 ] took maturation-induced pores in kerogen and inorganic pores into consideration and estimated organic content and total porosity based on density data.
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Impact of a Low Severity Fire on Soil Organic Carbon and Nitrogen

Impact of a Low Severity Fire on Soil Organic Carbon and Nitrogen

Ugawa, S., Takahashi, M., Morisada, K., Takeuchi, M., Matsuura, Y., Yoshinaga, S., Araki, M., Tanaka, N., Ikeda, S., Miura, S., Ishizuka, S., Kobayashi, M., Inagaki, M., Imaya, A., Nanko, A., Hashimoto, S., Aizawa, S., Hirai, K., Okamoto, T., Mizoguchi, T., Torii, A., Sakai, H., Ohnuki, Y., & Kaneko, S. (2012). Carbon Stocks of Dead Wood, Litter, and Soil in the Forest Sector of Japan: General Description of the National Forest Soil Car- bon Inventory. Bulletin of FFPRI, 11, 207-221. (In Japanese)

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Reconnaissance Lithological-Geochemical Exploration For Organic Matter And Total Organic Carbon In The Late Campanian-Paleocene Black Shale Belt, Upper Egypt

Reconnaissance Lithological-Geochemical Exploration For Organic Matter And Total Organic Carbon In The Late Campanian-Paleocene Black Shale Belt, Upper Egypt

The provided factual data about the organic matter bearing black bituminous and oil shale in Western Desert, Nile Valley and Red Sea coastal zone of Egypt point to a promising potential source of energy. These black shales in Egypt belong to three stratigraphic formations namely Duwi at the base overlain by the Dakhla and the lower Calcareous Member of the Esna Formation. The objectives of the present study concern the stratigraphic position, lithological characteristics, hosted total organic matter (O. M.) and total organic carbon (TOC) contents in relation to depositional environments of the formations forming the black shale belt. Lithologicaly these shales are distinguished by presence of mud bands and goethite cubes pseudomorph after pyrite favoring deposition in oscillating marine environment from shallow neritic to inner neritic (littoral to sub-littoral) reducing environment supplied with muddy argillaceous sedimentation. The recorded organic matter in Duwi Formation is ranging from 22.33 wt. % (El Sebaiya) to 0.73 wt. % (Kom-Mir) in the Nile Valley, 28.08 wt. % (El Nakheil) to 8.12 (Zug El Bahar) in the Red Sea Coastal Zone, in the Dakhla Formation 13.49 wt. % (Eldeir) to 1.60 wt. % (Kom-Mir) in the Nile Valley, 16.91 wt. % (W. Abu Shigeila),1.61 wt. % (G. Duwi) in the Red Sea Coastal Zone, 14.61 wt. % to 3.49 wt. % (G. Gifata) in the Nile Valley and from 12.42 wt. % (W. Abu Shigeila) to 2.27 wt. % (G. Duwi) in the Red Sea Coastal Zone. The total organic carbon content ranges from 22.15-0.22 wt. % in the Duwi Formation, 0.82-0.13 in the Dakhla Formation and 0.14-0.11 in the Esna Calcareous Shale. The determined Total Organic Carbon contents in twenty samples are potentially suitable for petroleum: (Excellent-2 samples, very good-5 samples, good-9 samples, fair-3 samples, poor 1). The impact of the depositional environments of each formation on the O. M. and TOC contents is obvious.
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Probabilistic Estimation of Shale-Oil Resources in 93 Global Formations in 36 Countries

Probabilistic Estimation of Shale-Oil Resources in 93 Global Formations in 36 Countries

I employed a probabilistic approach to the volumetric estimation of the original-in- place shale oil (OOIPsh_oil) in 93 formations from these 36 countries (and the US) belonging to seven geographical regions. This was followed by reservoir-simulation studies of five US formations whereby generalized-recovery-factor (RF) distributions were established for three values of hydraulic-fracture stage spacing. These generalized- RF distributions were used to compute the technically-recoverable resources of shale oil (TRRsh_oil) from the 93 formations considered. The results were aggregated to regional and global levels assuming 100% dependence (arithmetic aggregation) as well as 100% independence (statistical aggregation) between summand formation-wise resource distributions.
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Shale Gas Content Calculation of the Triassic

Shale Gas Content Calculation of the Triassic

calculation method of the lost time, and determines the temperature balance time of water 170.. heating.[r]

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A dual-tube model for gas dynamics in fractured nanoporous shale formations

A dual-tube model for gas dynamics in fractured nanoporous shale formations

In this paper we propose a simple model that allows us to estimate the production rate from fractured nanoporous shale. This model is based on the recognition that fractures contain a negligible gas volume and are much more permeable than the shale-rock matrix. As a result, the production rate is primarily controlled by the gas travel time from micro- or nanopores to the fracture system. In § 2 , we briefly analyse the geological structure of fractured shale formations and we discuss how the different components can be modelled. In § 3 , we review the physics of gas transport in shale formations, and in § 4 we present a simple dual-tube model that includes all the relevant gas-transport mechanisms in an effective diffusion coefficient. In § 5 we investigate the effects of pore-geometry variability, which are described by a bundle-of-dual-tubes model (BoDTM) that permits a stochastic description of the production rate and allows for great flexibility in dealing with multiporous material; and in § 6 we compare the results of the BoDTM with field data from the Barnett shale-gas field. Finally, conclusions are drawn and possible extensions of the model are discussed in § 7 .
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Study of the mechanical properties of low carbon content HSLA steels

Study of the mechanical properties of low carbon content HSLA steels

bainite lead to a lower steel strength than where there was lower bainite. This was also due to the high acicular ferrite content observed at high temperatures. For the V steel no significant differences were found. The values were always lower compared to V+Nb. The addition of vanadium, though might enhance the toughness by controlling the microstructure of the acicular ferrite [19 and 30] ,

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Soil Microbial Activity and Organic Carbon Dynamics in Low Input Agroecosystems.

Soil Microbial Activity and Organic Carbon Dynamics in Low Input Agroecosystems.

long periods of time have been found to have highly increased levels of stable aggregates. Tillage has been found to reduce aggregate stability by numerous researchers (Bhattacharyya et al., 2009; Chan et al., 1994; Roldan, 2003; Ryan et al., 2011; Tivet et al., 2013). Our data may reflect the lack of a substantial organic C source in no-cover crop plots to create aggregates resistant to tillage over the winter and spring. Such an effect has been suggested before, although others noticed this effect after treatments may be even on a longer time frame-up to 10 years (Abdollahi and Munkholm, 2014). Interestingly, NP soil that was not tilled had higher aggregate MWD than any cover cropped soil in at mid-season in 2012, while all NP plots had MWD similar to HV and CC prior to cover crop termination. In 2012, when this difference was apparent, NP plots were drier than either HV or CC pre-kill and post-kill (Table 2.5), possibly due to lack of ground cover to conserve soil moisture. It has been found that drying contributes substantially to increases in aggregate stability in the short term (Cosentino et al., 2006). Such results highlight the importance of within-season variability in explaining some soil physical phenomena at shorter time scales.
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Soil Organic Carbon Content and Quality in Post-Agricultural Northern Hardwood forests

Soil Organic Carbon Content and Quality in Post-Agricultural Northern Hardwood forests

Agricultural practices are known to diminish soil organic carbon (SOC) stocks and alter carbon quality. We surveyed a diverse set of sites in heterogeneous landscapes to determine past land use histories and ages of agricultural abandonment in order to examine changes to and spatial controls on soil carbon pools. Soils were sampled using quantitatively excavated pits, to the extent of the rooting zone. Three regions (i. western New England (WNE); ii. southern Wisconsin; iii. northern Wisconsin) of northern hardwood forests with different patterns of agriculture abandonment, varying soil types and properties, and differing climates were examined. Carbon (C) and nitrogen (N) concentrations were measured and contents calculated using bulk-density relationships. In WNE, soils formerly used for agricultural practices accumulated soil organic carbon (SOC) at a rate of 0.33 Mg ha-1 y-1 for the first century of forest regeneration. Formerly plowed soils accumulated C in the organic (Oe + Oa), 0-10 cm, and deep mineral soil (> 20 cm), while formerly pastured or hayed soils accumulated C in the organic horizons and 10-20 cm portion of the mineral soil. Sites used for subsistence logging showed no accumulation trends. As expected, N accumulated with C, although the patterns of N accumulation were more varied. Physical fractionation of the top 20 cm of mineral soil (the maximum depth to which these soils were plowed) showed that the pool of C associated with soil minerals increased with stand age (0.04 Mg ha-1 y-1), but that modern agricultural soils possessed as much C in this fraction as the oldest forests. A two-month incubation of these soils demonstrated 48% more C was respired (as CO2) in modern agricultural fields than abandoned forests. Multivariate regression tree results demonstrated that the time since agricultural abandonment and climate were important determinants of SOC amounts within the western New England landscape. When those sites were compared with other northern hardwood forest soils from the Adirondack region of New York, the Green Mountains of Vermont, southern Wisconsin and
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Organic carbon content and mineralization characteristics of soil in a subtropical Pinus massoniana forest

Organic carbon content and mineralization characteristics of soil in a subtropical Pinus massoniana forest

4.3 Similar organic carbon mineralization characteristics were observed for each soil layer in the examined P. massoniana forests. In particular, the mineralization intensity was initially strong but decreased over the course of the reaction period. A study by Collins et al. suggested that during the early stages of mineralization, monosaccharides and other readily decomposed active organic carbon-based compounds in soils undergo rapid decomposition. As these compounds are decomposed and consumed, by the later stages of mineralization, microbes are forced to break down organic carbon compounds that are difficult to decompose, resulting in a gradual decrease in decomposition rates and an accompanying reduction in CO 2 emissions[22]. A second explanation for the observed
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Effect of organic fertilizers on soil organic carbon and risk trace elements content in soil under permanent grassland

Effect of organic fertilizers on soil organic carbon and risk trace elements content in soil under permanent grassland

Labile dissolved organic carbon (DOC) is repre- sented by a complex mixture of organic molecules of varied origin that occurs in soil solution. Leinweber et al. (1995) supposed that water-extractable organic carbon is the main component of labile organic car- bon, and whether or not a particular organic molecule is dissolved in water depends on the water content, nature of the surfaces and other solutes. DOC is very active in carbon pool and its chemical composi- tion and mobility (smaller and more polar organic molecule) directly affect biological soil properties because of providing energy and nutrients. Zsolnay (2003) defined dissolved organic matter (DOM) (with the possible exception of the colloids) in the hydrosphere by size limit (= through filtration). The size limit, which is used to differentiate DOM from particulate organic matter, is arbitrary, nevertheless there is an almost universal consensus that it is around 0.45 µm. Another potential problem of DOM defini- tion is possible structural artefacts in DOM caused by abnormally high concentrations and drastic pH changes. Associations between DOC, heavy metals, and other hydrophobic pollutants were studied by Rook (1974) and Hayes and Clapp (2001). It was proved that fulvic acids, as the precursor of carci- nogenic pollutants, are harmful to human health. Ghani et al. (2003) and Uchida et al. (2012) quoted that labile organic carbon is responding to changes in rhizosphere caused by management practices and is considered as an important indicator of soil qual- ity/health. Many studies have reported about DOC changes and their dynamic, which is influenced by grazing, fertilization, mowing, and mulching (Haynes 2000; Váchalová et al. 2013). Monteith et al. (2007) supposed that the content of DOC could increase in soil solution with a warmer climate,
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Pyrogenic Carbon in Soils: A Literature-Based Inventory and a Global Estimation of Its Content in Soil Organic Carbon and Stocks

Pyrogenic Carbon in Soils: A Literature-Based Inventory and a Global Estimation of Its Content in Soil Organic Carbon and Stocks

Pyrogenic Carbon in Soils: A Literature-Based Inventory and a Global Estimation of Its Content in Soil Organic Carbon and Stocks Reisser, Moritz ; Purves, Ross S ; Schmidt, Michael W I ; Abiven, Samuel Abstract: Pyrogenic carbon (PyC) is considere done of the most stable components in soil and can represent more than 30% of total soil organic carbon (SOC). However, few estimates of global PyC stock or distribution exist and thus PyC is not included in any global carbon cycle models, despite its potential major relevance for the soil pool. To obtain a global picture, were viewed the literature for published PyC content in SOC data. We generated the first PyC database including more than 560 measurements from 55 studies. Despite limitations due to heterogeneous distribution of the studied locations and gaps in the database, we were able to produce a world wide PyC inventory. We found that global PyC represent on average 13.7% of the SOC and can be even up to 60%, making it one of the largest groups of identifiable compounds in soil, together with polysaccharides. We observed a consistent range of PyC contentin SOC, despite the diverse methods of quantification. We tested the PyC content against different environmental explanatory variables: fire and landuse (fire characteristics,land use,net primary productivity), climate (temperature, precipitation, climatic zones, altitude),and pedogenic properties (clay content, pH, SOC content). Surprisingly, soil properties explain PyCc ontent the most. Soils with clay content higher than 50% contain significantly more PyC (>30% of the SOC) than with clay content lower than 5%(<6% of the SOC). Alkaline soils contain at least 50% more PyC thanacidic soils. Furthermore, climatic conditions, represented by climatic zone or mean temperature or precipitation, correlate significantly with the PyC content. Byc ontrast, fire characteristics could only explain PyC content, if site-specific information was available. Datasets derived from remote sensing did not explain the PyC content. To show the potential of this database, we used it in combination with other global datasets to create a global world wide PyC content and a stock estimation, which resulted in a round 200 PgPyC for the upper most 2m. These modeled estimates indicated a clear mismatch between the location of the current PyC studies and the geographical zones where we expect high PyC stocks.
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