Total Organic Carbon Values Research Articles

Study of organic pollution indicators in two stations of the Garmat Ali River, Basra, Iraq

Water is one of the most important natural sources for sustaining life, as human life and various activities depend on it. The current study dealt with knowing the effect of organic pollution on physical and chemical properties in Garmat Ali river, which was represented in two stations, the first station called Al-Mashab, and the second Al-Sindbad. Water and sediment samples were collected monthly during the period from August, 2016 to July, 2017. Numbers of physical and chemical variables were measured during this period (water temperature, light penetration, pH, Salinity, dissolved oxygen, biological demand oxygen, chemical demand oxygen, total nitrogen, total phosphorus and total organic carbon in sediment). The results of the study was showed that water temperature were ranged between 13.2-31.3°C for the first station and 13.4-33.1°C for the second station. The light penetration values were ​​ranged between 20.6-58.5 cm for the first station and 35-65 cm for the second station. The pH values were ​​ranged between 7.5-8.6 for the first station and 7.5-8.5 for the second station. Salinity values were ​​ranged between 1.58-3.16 g/l for the first station and 0.92-2.13 g/l for the second station. Dissolved oxygen values were ​​ranged between 4.66-10.8 mg/l for the first station and 11.85-6.26 mg/l for the second station. The values ​​of BOD5 were ​​ranged between 1.1-4.26 mg/l for the first station and 0.75-4.06 mg/l for the station. The values ​​of the COD were ranged between 8-120 mg/l for the first station and 8-61 mg/l for the second station. Total nitrogen values were ​​ranged between 2.8-29.4 mg/l for the first station and 2.4-33.6 mg/l for the second station. The total phosphorus values were ​​ranged between 1.11-19.6 mg/l for the first station and between 1.24-19.98 mg/l for the second station. Total organic carbon values were ​​ranged between 0.36-2.19% for the first station and 0.32-2.94% for the second station. The two stations were recorded a little increased in organic pollution levels during summer months and first station (Al-Mashab) was most affected.

Shallow burial shale gas accumulation pattern of the Wufeng–Longmaxi Formations in the northern Guizhou area, western Yangtze platform

Although continuous breakthroughs of economic shale gas exploitation have been made globally within the middle–deep buried depth (∼1500–3500 m), the shallow–buried (less than 1500 m) shales are also widely distributed, showing excellent exploration prospects. However, the shale gas accumulation (SGA) pattern of the shallow burial shale remains unknown, limiting future shale gas exploration. To investigate the SGA pattern and the exploration potential of shale gas in shallow–buried shales, experiments such as X–Ray Diffractometer, N2 and CO2 adsorption, Focused Ion Beam Scanning Electron Microscopy (FIB-SEM), total organic carbon (TOC) content, gas chromatography–mass spectrometry, and field gas content test were carried out based on three wells penetrated the Wufeng–Longmaxi Formation with the buried depths of less than 700 m in the Northern Guizhou area, western Yangtze Platform. The geochemical and mineral records indicate that the organic matter is enriched as a result of global climate and regional tectonic activity, indicating the sufficient gas generation potential. The results of low pressure N2 and CO2 adsorption, as well as images of the FIB–SEM show that the mesopores are controlled by the organic matter, and the micropores, which are associated with minerals (primarily clays), can provide much more specific surface area and pore space in shallow–buried shales. Furthermore, carbonates with low porosity and permeability from the Songkan, Jiancaogou and Baota Formations, and the shale interval with low TOC values, weak brittleness, and low porosity, can serve as good roofs and floors for the SGA. Despite the fact that multi–stage tectonic movements resulted in the formation of faults and fractures, the good preservation, adequate gas storage space, and sufficient hydrocarbon generation potential contribute to the SGA in the shallow–buried shale.

Near equatorial paleoclimatic evolution and control on organic matter accumulation during the Cenomanian in the Abu Gharadig Basin, southern Tethys: Insights from palynology, organic petrography, and geochemistry

The beginning of the Late Cretaceous (Cenomanian) attested to a major marine transgression interrupted by sea level falls in north Africa, which led to significant environmental perturbation and widespread accumulation of organic matter-rich sediments. During this period, northern Egypt was located at the southern edge of the Tethys Ocean and deposition of thick siliciclastic alternations between shales, siltstones, and sandstones of the Bahariya Formation took place in the BED2 gas field of the Abu Gharadig Basin, north Western Desert. An integrated approach of palynofacies analysis and palynomorph composition, organic petrography, and geochemical analysis of total organic carbon (TOC)/Rock-Eval pyrolysis, carbonate content, XRD analysis, and clay mineralogy of thirty-nine cutting samples obtained from the lower-middle Cenomanian Bahariya Formation was conducted. This approach was used to characterize organic matter and possible occurrence of source rock intervals, paleoenvironmental and paleoclimatic conditions and their role in organic matter accumulation. Moderate to high proportions of pteridophyte and water fern spores and pollen grains of Araucariaceae (Araucariacites), Cheirolepidiaceae (mainly Classopollis), and Gnetalean (Elaterate pollen) and Afropollis versus the sparsely recorded xerophilous ephedroids (Ephedripites) indicate prevalent conditions of a warm and humid climate. This is consistent with clay mineral composition that is dominated mainly by kaolinite and smectite compared to low illite and the lack of chlorite, which indicated a predominantly warm-humid climate state. Palynofacies analysis showed two assemblages; the first one is dominated by phytoclasts and indicates gas-prone Type III kerogen and deposition in a fluvio-deltaic environment. The second palynofacies assemblage is characterized by moderate abundance of phytoclasts and AOM mostly of terrestrial origin, suggesting a mixed Type III/II kerogen and deposition in a marginal to shallow neritic shelf environment. The organic geochemical characterization showed relatively low average values of TOC, S2, and HI, indicating that the Bahariya Formation is characterized by Type III gas-prone kerogen. Thermal maturity of the Bahariya Formation ranges from immature to the early stage of the oil window. Additionally, organic matter characteristics of the Bahariya Formation are qualitatively and quantitatively similar to their equivalents from nearby basins. Low TOC contents are attributed to a high sedimentation rate and an increased terrestrial input of sand- and silt-sized fractions at shallow water column settings that controlled strong dilution and decomposition versus low burial efficiency of the organic matter.

Hydrocarbon Generation from Low-Mature Saline Lacustrine Sediments Studied Using Machine Learning and Chemometric Methods: The Succession of the Sikeshu Sag, Junggar Basin, NW China.

Significant attention has been given to the extensive development of saline environments in petroliferous basins. Further exploration and studies have discovered that saline environments, such as those for the deposition of source rocks in the Paleogene Anjihaihe (E2-3 a) Formation of the Sikeshu Sag, are ubiquitous in terrestrial lake basins. Previous studies have suggested that the oil reservoirs in the Sikeshu Sag and its peripheral regions are predominantly derived from the black mudstone and coal measures of the Lower Jurassic Badaowan (J1 b) Formation. However, with deeper exploration of the study area, a growing number of reservoirs with geochemical characteristics different from the J1 b oil source have been discovered, indicating that there are oil sources other than the J1 b source rocks. In this study, various machine learning algorithms were used (random forest, RF; convolutional neural networks, CNN; extreme gradient boosting, XGBoost; ElasticNetCV; Bayesian Ridge; and particle swarm optimization-support vector regression) to select the most suitable algorithm for predicting and comparing the quality of potential source rocks. A violin plot and Taylor diagram were applied to visually compare the reliability and application effectiveness of the models. The results demonstrated that XGBoost and RF can become essential tools for predicting the quality of potential source rocks. Moreover, the measured and predicted values of total organic carbon (TOC), hydrocarbon potential (S1 + S2), and hydrogen index indicate that there are three main source rocks: the E2-3 a, Lower Jurassic Sangonghe (J1 s), and J1 b formations. The thermal maturity of the E2-3 a source rocks is still early mature because of the saline-brackish water nature of these rocks, although large-scale hydrocarbon generation and expulsion can be achieved in the early mature stage. Based on their geochemical characteristics and stepwise discriminant analysis, the oils in the Sikeshu Sag and its peripheral regions can be categorized into two types: groups A and B. Comprehensive organic geochemical evidence suggests that genetically, group A oils are originated from E2-3 a less-mature saline lacustrine sedimentary rocks, while group B oils indicate similar affinity to the Jurassic source. Fluid inclusion microthermometry and one-dimensional basin modeling showed that the oil charging periods of group A and B oils were Middle-Late Miocene (13-8 Ma) and Late Oligocene (23-20 Ma), respectively. Quantitative grain fluorescence (QGF) analysis further propose that the hydrocarbon supply region of the E2-3 a sources is mainly located east of the Western Chepaizi Uplift and the interior area of the Sikeshu Sag, which breaks through the previous understanding that the Jurassic coal-derived oil source is the only main contributor in this study area. The research results can be widely applied to assess the petroleum resources of source rocks in similar areas worldwide.

Preliminary results of petroleum source rock evaluation of Mongolian Mesozoic oil shales

Jurassic and Cretaceous oil shale samples, collected from northern and central Mongolian basins, have been analyzed to determine their petroleum source rock potential. The contents of total organic carbon (TOC) and total sulfur, and source rock screening data were obtained by Rock-Eval pyrolysis. Cretaceous oil shales contain up to 17.4 wt.% TOC and Hydrogen Index (HI) values range from 638-957 mg HC/g TOC. Jurassic oil shale samples have similar TOC contents, ranging from 10.7 to 17.3 wt.%. HI values of Jurassic Tsagaan-Ovoo oil shale vary between 270-313 mg HC/g TOC. Average Tmax values of Cretaceous and Jurassic samples are 4370C and 4230C, respectively. This observed data indicates that both Jurassic and Cretaceous oil shales are excellent source rock. Cretaceous oil shales contain type I kerogen (highly oil prone), while Jurassic Tsagaan-Ovoo oil shale has mixed type II/III kerogen (mixed oil and gas prone). Based on Tmax and Production Index values, both Jurassic and Cretaceous oil shales are immature. Overall, the result of this study contributes organic geochemistry database of Mongolian oil shale and encourages source rock potential of both Jurassic and Cretaceous oil shale.

Impact of Terrigenous Organic Matter Input on Organic Matter Enrichment of Paleocene Source Rocks, Lishui Sag, East China Sea

To clarify the organic matter (OM) enrichment of the Lishui Sag, the factors influencing the variable abundance of OM in the Lingfeng Formation are studied using organic geochemical data. The source rocks of the Lingfeng Formation have medium–high total organic carbon (TOC) values (0.53–3.56%). The main type of kerogen is II2-III. Compared to the shallow marine subfacies source rocks, the TOC of the delta front subfacies source rocks is higher. The distribution of biomarkers shows that the redox environment of the delta front subfacies source rock is the sub-oxidizing and oxic environment, and the source rock is mainly supplied by terrigenous higher plants; the redox environment of shallow marine subfacies source rocks is a sub-reducing and suboxic environment, and the OM mainly comes from algae. The link between OM input and OM abundance demonstrates that terrigenous OM (TOM) input has a considerable influence on OM abundance. However, there is no obvious relationship between preservation and OM abundance, which suggests that preservation is not the determining element in OM enrichment. The strong sediment flux decreases the amount of time that OM is exposed to oxygen. As a result, delta front subfacies with large TOM input have a huge number of excellent source rocks. This paper proposes a “delta front-OM input model” for excellent source rocks.

Characteristics and Significance of Acid-Soluble Organic Matter in Marine Carbonate Source Rocks

Since the 1950s, major breakthroughs have been made in the field of carbonate oil and gas exploration, and large reservoirs have been found in carbonate strata in many countries; however, the validity of highly evolved carbonate source rocks has been controversial. Because of the loss of organic carbon during acid-solution processing in conventional total organic carbon (TOC) determination, we decided to use a new method of reducing acid-solution losses in order to more effectively quantify acid-soluble organic matter in carbonate rock samples. Different levels of acid-soluble organic matter were present in different types of samples, and there was no positive correlation between the content of acid-soluble organic matter and conventionally measured TOC values. However, the thermal evolutionary maturity of samples with high acid-soluble organic matter content is relatively low, and the high hydrocarbon generation conversion rate of acid-soluble organic matter and conventional TOC in carbonate rocks is an important reason for the low residual TOC in highly evolved carbonate rocks. The new method is helpful in re-evaluating the abundance of organic matter in carbonate rocks and in providing evidence for studying hydrocarbon generation and the hydrocarbon capacity of carbonate source rocks.

Environmental controls on the microfacies distribution and spectral gamma ray response of the uppermost Jurassic–Lowermost cretaceous succession (Pimienta–Lower Tamaulipas Formations) in central-eastern Mexico

Organic-rich sediments of the Pimienta Formation were deposited in the Tampico-Misantla Basin during the Late Jurassic–Earliest Cretaceous. A sedimentological, spectrometric, microfacies and geochemical analysis was performed on a stratigraphic section recording the Pimienta–Lower Tamaulipas formational transition, to gain an understanding of the depositional conditions, and to decipher the main factors that control the gamma ray signal. This latter was achieved by comparison with other records. The studied succession spans from the upper part of the lower Berriasian Calpionella Zone to the lower part of the lower Valanginian Calpionellites Zone. Moreover, the microfacies data indicate it was accumulated in an outer ramp to basinal setting influenced by high energy events and the input of grains transported from shallower areas. Oxygen levels increased during the lastest Berriasian–early Valanginian. The organic matter preserved in these sediments has a mixed marine-terrestrial origin and is immature to early mature. Several records across the basin show that from the lower part of the Pimienta Formation to the lower part of the Tamaulipas Formation sediments change from radiolarian-rich microfacies with the highest Total Organic Carbon (TOC) content and Standard Gamma Ray (SGR) values to calpionellid-rich microfacies with the lowest TOC and SGR values. This shift is interpreted as controlled by the evolution of environmental conditions from eutrophic/oxygen-depleted to oligotrophic-partially oxygenated, which caused a progressive decrease in the organic matter burial and enrichment of authigenic U.

Pyrolytic and provenance evaluation of organic matter from the tertiary niger delta basin, nigeria: implication on hydrocarbon generation.

The present work deals with evaluation of organic matter based on detailed Rock-Eval pyrolysis techniques studies to evaluate hydrocarbon generation potential of source rocks by collecting twenty- nine shale samples from well cuttings in the Tertiary Formations of the Niger Delta, Nigeria. The values of vitrinite reflectance (0.57–0.74%Ro) and maximum (Tmax: 420–445°C) confirmed that samples are at early maturity to matured stage enough to generate liquid and gaseous hydrocarbon. The cross-plot between hydrogen index (HI) and oxygen index (OI) atomic ratio indicates that samples were predominant in the bituminous rank and having kerogen Type III makes it suitable for hydrocarbon generation. Rock-Eval pyrolysis analysis (Types II-III and Type III kerogen) on shale samples from the Niger Delta reveals organic matter of predominantly terrestrial origin based on type III kerogen. The organic matter (OM) assemblages suggests a marine setting but dominated by terrestrial inputs likely related to fluvial processes which is function of most delta system. Based on high total organic carbon (TOC) value of 5.42wt% and Type III kerogen made the shale an excellent source rock, with gas-prone kerogen. The high OI, low total sulphur (TS) suggests terrestrially derived OM and deposition in an oxic and dysoxic shallow marine environment. In addition, HI and Tmax values describe the samples as a characteristic Type III dominant kerogen and potential to generate oil and gases while the Tmax, consistently indicate an immature to mature on the shale organic matter.

An evaluation of the hydrocarbon potentials of the gboko formation, middle benue trough, nigeria

A total of seventeen (17) rock samples from the Albian Gboko Formation were collected from the quarry of Benue Cement Company for organic geochemical analysis, in order to evaluate its hydrocarbon potential . Total Organic Carbon (TOC) values for the samples ranges from 0.11-0.5wt%. The rock-eval data recorded S2, hydrogen index (HI), Oxygen index (OI), Tmax, and production index (PI) of 0.04-0.11, 25-54, 50-400, 310-4610C, and 0.4-0.6, respectively. These implies that the samples has a fair to poor source rock quality with a type IV kerogen. Optical methods (R0, TAI & VKF) conducted on three selected samples of shales reveal vitrinite reflectance (R0) of 0.77%, 1.11% and 1.54%, while thermal alteration index (TAI) recorded 2.7, 3.3 and 3.7. Kerogen fluorescence indicated weak to non fluorescence. These results infer that the sediments had evolved from oil to gas window due to severe thermal effects . This indicates their potential to generate hydrocarbon gas

Thermal Maturity and Kerogen Type of Badenian Dispersed Organic Matter from the Getic Depression, Romania

The aim of this study is to evaluate the thermal maturity of Upper Badenian (Middle Miocene) petroleum source rocks of the Getic Depression, Romania, and to characterize the dispersed organic matter using organic petrography associated with Rock-Eval pyrolysis. A total of 33 core samples of Upper Badenian source rocks from the central–southern part of Getic Depression was studied. The results show that most samples with values of total organic carbon (TOC) < 1% wt.% have a limited potential of hydrocarbons (HC) generation, and 30% of samples with TOC < 1.82 wt.% and kerogen type III, presenting particularly gas generation potential. In three samples from the Bibești, Grădiște and Socu structures the kerogen type III-II was identified, indicating the capability of oil and gas generation. The Badenian source rocks are thermally immature, as few samples are in the pre-oil window, with values of vitrinite reflectance (VRo%) ranging between 0.41% and 0.55%, and the values of Tmax between 409 °C and 443 °C. Optical microscopy with reflected white light and fluorescence blue light was used for identification of terrigenous macerals (vitrinite, liptinite as, resinite, cutinite, sporinite, and inertinite) associated with marine liptinite macerals (telalginite and lamalginite) showing yellow and bright–yellow epifluorescence.

A comprehensive methodology for analysis of coagulation performance: Dosing approach, isotherm modelling, FTIR spectroscopy and floc characterization

Isolated studies for the evaluation of coagulation considering either microscopic or macroscopic dimensions have largely been discussed. However, comprehensive analysis of coagulation including various dimensions is imperative to design an optimal coagulation system. In this work, a comprehensive methodology has been described which includes dosing approach, mathematical modelling, chemical analysis by FTIR (Fourier Transform Infrared) spectroscopy, image analysis for floc properties and various analytical procedures. Jar tests were performed on simulated waters containing humic acid and kaolin using high basicity PACl (Poly Aluminium Chloride). A PODR (point of diminishing return) approach is used for the determination of coagulant dose corresponding to TOC (Total Organic Carbon), DOC (Dissolved Organic Carbon) and UV254 (Ultraviolet Absorbance at 254 nm). On average, PODR for UV254 was slightly greater than that of TOC followed by that of DOC. The correlation between the input TOC and PODR values was in the order: TOC (R2 = 0.84) > UV254 (R2 = 0.83) > DOC (R2 = 0.65). The isotherms are analyzed by non-linear error functions: RMSE (Root mean square error), HYBRID (Hybrid fractional error function), ARE (Average relative error), MPSD (Marquardt's percent standard deviation) and Chi-Square. It was observed that error functions RMSE, HYBRID and Chi-Square can be successfully used for non-linear analysis. However, ARE and MPSD cannot be used at low concentrations as they showed high residual values. Further, image processing is used to analyze floc size and fractal dimension. The interactions of species and the physical structure of flocs derived based on adsorption isotherms are corroborated by using the FTIR data.

Organic matter enrichment mechanism of Youganwo Formation oil shale in the Maoming Basin

The Youganwo Formation oil shale located in the Maoming Basin represents a large commercially valuable lacustrine oil shale resource and a potential bio-shale gas reservoir in South China. With the aim of deepening the understanding of factors that influence organic matter enrichment, this research conducted a geochemical investigation to reconstruct the depositional paleoenvironment of bioproductivity, preservation and dilution. Youganwo Formation oil shale is mainly deposited in semi-deep to deep-lake environments with relatively warm and humid paleoclimate in the subtropical-temperate zone. The total organic carbon (TOC) content (1.46–11.85%), S2 values (4.79–115.80 mg HC/mg rock) and HI (328–1040 mg HC/mg TOC) indicate that the oil shale has a good oil source rock potential. TOC content, (S1 + S2) values and vitrinite reflectance values show that its marginally mature organic matter (OM) belongs to kerogen type I-III with good oil-generating potential.A 3rd order sequence was identified in the Yougnwo formation. Subsequently, the multiple factors including bioproductivity, preservation and dilution that control the OM enrichment of oil shale within system tracts were discussed. Moderate-quality oil shales (Oy-1) were developed in the transgressive systems tract (TST) in an oxidizing condition with abundant detrital input. High-quality oil shales (Oy-2) were deposited during the high-stand systems tract (HST) with increased accommodation space, improved preservation conditions, warm and humid climate, higher water bioproductivity and minimum detrital matter input. During the regressive systems tract (RST, Oy-3), higher detrital matter input and fresher water led to lower TOC values. Among these multiple factors, dilution condition was the major one that influences OM abundance and variation on the basis of sufficient organic matter input. Thus, OM enrichment models of Oy-1, Oy-2 and Oy-3 sub-members were established. The OM enrichment and quality in oil shale were controlled by the combined effect of bioproductivity, preservation, and dilution.

Prediction of water quality extremes with composite quantile regression neural network.

Water quality extremes, which water quality models often struggle to predict, are a grave concern to water supply facilities. Most existing water quality models use mean error functions to maximize the predictability of water quality mean value. This paper describes a composite quantile regression neural network (CQRNN) model, which simultaneously estimates non-crossing regression quantiles by minimizing the composite quantile regression error function. This method can improve the prediction of extremes. This paper evaluates the performance of CQRNN for predicting extreme values of turbidity and total organic carbon (TOC) and compares with quantile regression (QR), linear regression (LR), and k-nearest neighbors (KNN) in an application to the Hetch Hetchy Regional Water System, which is the primary water supply for San Francisco, CA. CQRNN is superior to QR, LR, and KNN for predicting the mean trend and extremes of turbidity and TOC, especially for the non-Gaussian turbidity data. The performance of CQRNN is the most stable relative to other methods over different training sample sizes.

Factors controlling spatial distribution of complex lithology in transitional shale strata: Implications from logging and 3D seismic data, Shan-2 Lower Sub-member, Eastern Ordos Basin

The Shanxi Formation Shan-2 Lower Sub-member transitional shale in the eastern Ordos Basin is characterized by high total organic carbon value, wide distribution, and large single-layer/cumulative thickness; it is the key target interval for transitional shale gas exploration. Based on drilling, logging, 3D seismic, and natural energy spectrum data, this study discusses the spatial distribution and controlling factors of complex lithology in the transitional shale stratum. Using the multi-lithological eigenvalue method, the lithologic differential distribution characteristics of the Shan-2 Lower Sub-member were identified through seismic attribute analysis and post-stack seismic parameter inversion. On this basis, the controlling factors of lithology spatial difference distribution are revealed by paleogeomorphology restoration, the sedimentary environmental indicator characteristics of shale, and seismic facies division. The results indicate that the lithology distribution of transitional shale strata in the Shan-2 Lower Sub-member is significantly different, and the geomorphological pattern of interjacent depressions and highlands lays a foundation for the formation of the sedimentary system. The environmental and energy differences of paleo-sedimentary water form a sedimentary environment with frequent facies transitions, which controls the distribution of sediments. Th/U and Th/K radios, which indicate redox conditions and sedimentary water energy during the early sedimentary stage of the Shan-2 Lower Sub-member, show that the geomorphic uplift area is characterized by a high-energy transitional environment of mainly developed sandstone and silty mudstone, while the depression is relatively low-energy under a brackish water reduction environment, mainly composed of both dark and carbonaceous shale. During the late sedimentary stage of the Shan-2 Lower Sub-member, when geomorphic control was weakened, it presented a shallow-water, high-energy, and oxidized transitional environment, with a lithology dominated by the complex interbedding of fine-grained sandstone, silty shale, shale, carbonaceous shale, and coal seam. Therefore, it is inferred that the Shan-2 Lower Sub-member may have developed as a barrier island-lagoon sedimentary model. The early depositional period was dominated by barrier island-lagoon-tidal flat depositional combination, thence the sedimentary environment gradually evolved into a tidal flat-swamp environment.

Thermal effect of igneous intrusions on organic-rich Irati Formation and the implications for petroleum systems: a case study in the Paraná Basin, Brazil

The organic geochemistry of organic-rich facies including shales, marls, and carbonates (Assistência Member) of the Irati Formation, Paraná Basin, Brazil, were analyzed to evaluate the thermal effects of igneous intrusions upon the kerogen present in these facies. Total organic carbon (TOC) content and hydrocarbon source potential (S2) of the Irati source rocks range from 0.03 to 20.4% and 0.01 to 112.1 mg HC/g rock, respectively, indicating excellent potential as a source for hydrocarbon generation. Hydrogen index (HI) values reveal that the kerogen is predominantly type I (HI: up to 892.6 mg HC/g TOC) and, therefore, an oil source, except for samples having low TOC content due to severe maturation caused by the heat from diabase intrusions. The thickness of igneous intrusions in the 64 wells investigated in this study ranged from 2 to 231 m. They clearly had a major impact on TOC, HI, and S2 values, which decrease in the vicinity of intrusions, indicating a gradual increase in maturation toward the igneous body. In wells without the influence of igneous intrusions, Tmax values of Rock-Eval pyrolysis and %Ro indicate that the organic matter is immature for the generation of hydrocarbons.

Characterization of Lower Cretaceous organic-rich shales from the Kom Ombo Basin, Egypt: Implications for conventional oil generation

• The shales of the Kom Ombo Formation are organic-rich sediments, with TOC value of up to 6.61 wt.%. • The organic facies are predominantly of Types II and II/III kerogen. • Kom Ombo shales were deposited in a marine under anoxic environmental conditions. • The shales reached peak oil-window and generated commercial amounts of oil. This study uses organic geochemical and petrographic analyses to characterise the organic-rich shales from the Lower Cretaceous Kom Ombo Formation in the Kom Ombo Basin. The overall results show that the Kom Ombo shales are considered to have good petroleum source rock potential with total organic carbon (TOC) content > 1 wt % and hydrocarbon yields of up to 27.62 mg hydrocarbons/g rock. Based on lipid biomarker ratios and carbon isotopes, the Kom Ombo shale contains a blend of organic matter derived primarily from algal marine and other aquatic organic matter, with some terrigenous land plants, deposited under anoxic conditions. These findings of organic matter (OM) input and depositional conditions are consistent with the high TOC content of up to 6.61 wt. % and mainly Types II and II/III kerogen, with small amounts of Type III kerogen, thus yielding both oil and gas, with oils of high to low wax contents. The geochemically determined dominance of oil generation potential is in agreement with the findings of considerable concentration of fluorescent liptinite macerals. The chemical and optical maturity results show that the majority of the examined Kom Ombo shale samples have entered the main stage of oil generation, exhibiting a range of early-mature to late-mature. Therefore, as highlighted in this study, the oil generation potential of the Kom Ombo shales may represent future conventional petroleum exploration opportunities.

Distribution and Enrichments of Abundant and Trace Elements in Al-Khassa Sub Basin Soil, Kirkuk, Northeastern of Iraq

This study focused on the soil of the Al-Khassa Sub Basin, thirty-four soil samples were collected from different areas of land use and differences in human activity. Physicochemical properties of the soil were examined Hydrogen Potential (pH), Organic Matter (O.M), Loss Of Ignition (L.O.I), Total Organic Carbon (TOC), Cation Exchange Capacity (CEC) and Total Hydrocarbon (THC). Hydrogen Potential (pH) showed that the soil is alkaline above seven with a mean 7.98. Organic Matter (O.M) of the study area with a mean 1.28 % and high value found in Agricultural areas.Cation Exchange Capacity (CEC) with a mean 42.64 (cmol/kg) that is proportional to the granular size of the soil that silty clay. Both Total Organic Carbon (TOC) and Total Hydrocarbon (THC) acceptable concentration values compared to the soils of the arid region. In the present study abundant elements (Calcium (Ca), Silicon (Si), Aluminum (Al), Magnesium (Mg), Sulfur (S), Potassium (K), Chloride (Cl), Titanium (Ti) and Phosphorous (P) ) and Trace element(Chromium (Cr), Manganese (Mn), Nickel (Ni), Zinc (Zn), Vanadium(V), Copper(Cu), Lead(Pb), Arsenic (As), Cobalt (Co), Mercury (Hg) and Molybdenum (Mo)) that have been analyzed in this study and compared with the limits to elements distribution in world soil and local study of Lesser Zab. Elements that are higher than standard Ca, Cl, Cu, As,Hg, Mo, Zn because of excessive use of fertilizers and pesticides and poor irrigation practice and other anthropogenic sources. High concentration elements (Ni, Ca, Co) as a result of the weathering of the parent rocks, it occurs naturally in soils. Other elements that were partially higher than the standard is (K, Cr, P, S, Mg( only in dense agricultural areas. Elements that were lower than Standard (Ti, Al, Si, Mn, V, Pb) represent the unpolluted elements at some locations the sub-basin because they are elements that increase in urban and industrial areas that are not available in the Al-Khassa Sub Basin, main activity and land use of sub basin were rural area and cultivated land. The results of the enrichment factor (EF) and the contamination factor (CF) are calculated for contamination assessment. The Enrichment factor (EF) of the sub-basin is EF 2 depletion to minimal enrichment, indicating no or minimal pollution, but there is a real beginning of contamination of the magnesium element EF 2-5 moderate enrichment, indicating a real beginning of contamination of the magnesium element. indicating of moderate pollution due to the presence of farms that were use of magnesium sulfate fertilizers by villagers at sedan. The results of the Contamination Factor (CF) showed that the region is low to moderate contamination Except for the contamination factor of magnesium in Mam Rash (S22), Belgrad (S10) was very high degree of contamination of Cf > 6, and in Sedan (S25), Gurgay Shammar (S11), and Obarick (S32) was considerable degree of contamination of magnesium 3 < Cf < 6 because of the three villages was agricultural area that use of magnesium fertilizer. Phosphor (P) contamination factor is moderate in Heon (S7), Ali Makaeel (S20) because they are villages that use phosphate fertilizers beside occurrence of poultry farms.

Study of Some Heavy Metals Concentrations from the Soil of Selected Areas at the ‎North Part of Basrah, Iraq

The current study was conducted in the north of Basra to show the state of contamination and how it is affected by different pollutants. including heavy elements and some important environmental indicators of the soil. The study period extended from September 2021 to June 2022 to determine the concentrations of some heavy metals in the soil in (wet-dry) where six elements were estimated, namely zinc, copper, lead, nickel, cadmium, and Iron in the exchangeable phase and the residual phase of the soil Heavy elements have been extracted by standard methods and determined by using an atomic absorption spectrometer, as well as the determination of total carbon organic matter (TOC %) and soil texture. Total organic carbon results are shown in the current study in the soil, where the highest value of total organic carbon (TOC %) was recorded in the dry season in Al-Hawyer region station-1which has a value of 0.480 % and a rate of 0.207 % . The lowest value, was 0.02 % and recorded in the AL-Deer Nillage at station-5, with a rate of 0.183 % but the highest value of carbon in the total organic matter (TOC %) in the wet season was recorded in the Al-Nashwa region (0.615 %) at station with a rate of 0.355 % and the lowest value of 0.125 % was in the Al-Hawyer region station-1, and at a rate of 0.16%. The results of heavy metals for the study area in the soil in the dry season of the exchangeable phase showed that the highest rate of elements (zinc, copper, lead, nickel, cadmium and iron) 60.18, 53.37, 22.95, 57.86, 7.46 and 720 μg/g respectively and the lowest rates recorded were : 20.94, 15.01, 11.96, 23.81, 3.11 and 502.32 μg/g As for the results of heavy elements in the residual phase of the soil (zinc, copper, lead, nickel, cadmium and iron), it recorded the highest rates : 93.24, 20.78, 31.63, 77.82, 9.98 and 751 μg/g where the lowest recorded rates were : 47.29, 8.08, 17.19, 53.28, 9.98 and 550.86 μg/g respectively in the wet season. The heavy weight of the study area in the soil of the exchangeable phase showed that the highest rate of the elements zinc, copper, lead, nickel, cadmium, and iron was: 152.70, 25.35, 20.07, 88.32, 6.73, and 703 μg/g respectively, the lowest recorded rat 17.24, 2.03, 17.10, 20.11, 2.69 and 274 μg/g respectively. The results of heavy metals in the residual phase. The residual zinc element ranged rate between 5.04-41.84 μg/g while the copper element ranged from 0-23.99 μg/g and the lead element ranged from 12.16-24.22 μg/g as for nickel, it ranged between 39.73 and 62.95 μg/g and cadmium ranged from 5.31-10.70 μg/g finally rates of iron elements were also between 504.18 and 721 μg/g.

Biocrude oil production from a self-settling marine cyanobacterium, Chroococcidiopsis sp., using a biorefinery approach

Although the whole microalgal biomass is typically used as a feedstock for hydrothermal liquefaction (HTL), the conversion of a primary metabolite (i.e., carbohydrate) to biocrude is very low. In this study, a self-settling cyanobacterium (i.e., Chroococcidiopsis sp.) was used to understand the effect of carbohydrate removal, as a pretreatment, on the net energy recovery from the residual biomass. The optimum biocrude yields from pretreated and control biomass were 50.2% (350 °C) and 41.3% (300 °C), respectively. For the temperature range studied, the biocrude yield from the pretreated biomass was higher compared to that obtained from the control feedstock. Further, maximum alkane formation of 42.7 and 23.3% occurred for pretreated and control biomass, respectively, at 325 °C. Total organic carbon and total nitrogen values in the aqueous phase liquid obtained from pretreated biomass were at least 1.31 and 1.23 times lower when compared to the corresponding values obtained from control biomass. When APL was recycled as a source of nutrients, it reduced the biomass yield (24.1%) and pigment content (68.4%) in Chroococcidiopsis sp. Further, a model was developed to understand how the cellular carbohydrate content would affect the net energy recovery for the proposed biorefinery route.