Relationships between porosity,organic matter,and mineral matter in mature organic-rich marine mudstones of the Belle Fourche and Second White Specks formations in Alberta,Canada     

《Marine and Petroleum Geology》2014

This study presents approaches for evaluating hybrid source rock/reservoirs within tight-rock petroleum systems. The emerging hybrid source rock/reservoir shale play in the Upper Cretaceous Second White Specks and Belle Fourche formations in central Alberta, Canada is used as an example to evaluate organic and inorganic compositions and their relationships to pore characteristics. Nineteen samples from a 77.5 m-long core were analyzed using organic petrography, organic geochemistry, several methods of pore characterization, and X-ray powder diffraction (XRD). The lower part of the studied section includes quartz- and clay-rich mudrocks of the Belle Fourche Formation with low carbonate content, whereas the upper portion contains calcareous mudrocks of the Second White Specks Formation. Strata are mineralogically composed of quartz plus albite (18–56 wt. %), carbonates (calcite, dolomite, ankerite; 1–65 wt. %), clays (illite, kaolinite, chlorite; 15–46 wt. %), and pyrite (2–12 wt. %). Petrographic examinations document that organic matter represents marine Type II kerogen partly biodegraded with limited terrestrial input. Vitrinite reflectance R_o (0.74–0.87%), T_max values (438–446 °C) and biomarkers indicate mid-maturity within the oil window. The relatively poor remaining hydrocarbon potential, expressed as an S2 value between 2.1 and 6.5 mg HC/g rock, may result from an estimated 60–83% of the original kerogen having been converted to hydrocarbons, with the bulk having migrated to adjacent sandstone reservoirs. However, the present-day remaining total organic carbon TOC_pd content remains relatively high (1.7–3.6 wt. %), compared with the estimated original TOC_o of 2.4–5.0 wt. %. The calculated transformation ratio of 60–83% suggests that the remaining 17–40 wt. % of kerogen is able to generate more hydrocarbons. The studied section is a tight reservoir with an average Swanson permeability of 3.37·10⁻⁵ mD (measured on two samples) and total porosity between 1.7 and 5.0 vol. % (3 vol. % on average). The upper part of the sandy Belle Fourche Formation, with slightly elevated porosity values (3.5–5 vol. %), likely represents the interval with the best reservoir properties in the studied core interval. Total pore volume ranges between 0.0065 and 0.0200 cm³/g (measured by a combination of helium pycnometry and mercury immersion). Mesopores (2–50 nm ∅) are the most abundant pores and occupy 34–67% of total porosity or a volume of 0.0030–0.0081 cm³/g. In comparison, micropores (<2 nm ∅) cover a wide range from 6 to 60% (volume 0.0007–0.0053 cm³/g), and macropores (>50 nm ∅) reach up to 57% with the exception of some samples failing to indicate the presence of this pore fraction (volume 0.0000–0.0107 cm³/g). Macroporosity is mostly responsible for variations in total porosity, as suggested by macroporosity's strongest correlation with total porosity within the section. The relatively narrow ranges of TOC and minerals contents among measured samples limit our ability to further deconvolute factors that influence changes in total porosity and pore size distribution.  相似文献   

Larval fish assemblages in a tropical mangrove estuary and adjacent coastal waters: Offshore-inshore flux of marine and estuarine species   总被引：1，自引：0，他引：1  

A.L. Ooi  V.C. Chong 《Continental Shelf Research》2011,31(15):1599-1610

A total of 92,934 fish larvae representing 19 families were sampled monthly from the Sangga Kecil estuary (Matang Mangrove Forest Reserve) and adjacent coastal waters from May 2002 to October 2003. Larval fish assemblages were numerically dominated by Gobiidae (50.1%) and Engraulidae (38.4%). Canonical Correspondence Analysis (CCA) revealed that the larval fish assemblages, including their ontogenetic stages, differed between the mangrove estuary and adjacent offshore waters, and that salinity, turbidity and zooplankton food are the major environmental factors structuring the larval fish assemblages. Estuarine preflexion gobiid larvae were ubiquitous in the coastal and estuarine waters. Larval stages of euryhaline species that were spawned in offshore waters, such as Engraulidae and Clupeidae, were largely advected into mangrove areas at the postflexion stages. Larvae of other euryhaline fishes (Sciaenidae, Blenniidae and Cynoglossidae) that may have been spawned inside the estuary were, however, exported to offshore waters. Given that the collective number of juvenile and adult fish families in the Matang estuary was 53, while the number of larval families was only 17, the former is quite disconnected from the existing larval fish population in the estuary.  相似文献   

The geochemistry of aliphatic and polar organic tracers in sediments from Lake Bera, Malaysia     

Noorhazlina Abu BakarKheng Soo Tay  Nasr Yousef M.J. OmarM. Radzi Bin Abas  Bernd R.T. Simoneit 《Applied Geochemistry》2011,26(8):1433-1445

The molecular distributions of homologous aliphatic lipid compounds (n-alkanes, n-alkanoic acids, n-alkanols, n-alkanals and n-alkan-2-ones) were investigated in sediments of Lake Bera, Malaysia as well as in plant waxes from the vicinity using gas chromatography-mass spectrometry. In addition, triterpenoids of the oleanane, ursane, lupane and friedelane series, and their diagenetic products were also identified. Using the aquatic proxy P_aq, it was found that the n-alkanes present in surface sediments S1, S5 and S6 correspond to an input from emergent macrophytes, whereas in sediments collected from open water (S2, S3 and S4) they correspond to input from submerged/floating macrophytes. The presence of n-alkan-2-ols, a commonly found homologous series in the sediments as well as in the plant wax, is novel here. In addition, the presence of 24-methylcycloart-22-enol and 24-ethylcycloart-22-enol in sediments as well as the plant wax of Pandanus helicopus, a dominant reed around the lake, also supports the input of plant biomarkers to the sediments. The occurrence of 5-membered ring triterpenoid derivatives as major diagenetic products of the triterpenoids identified (e.g. friedelan-2,3-dione) shows that the degradation of the organic matter in the sediments occurs mainly under oxic conditions. Also, the presence of ring-A degraded triterpenoids (dihydroputranjivic acid, 3-nor-2,4-seco-friedelane, 4α- and 4β-3-norfriedelanes, A-norfriedel-10-one, and A-norfriedel-8-en-10-one) and the aromatized triterpenoid hydrocarbons (mono- and triaromatic derivatives) as minor diagenetic products indicates photochemical and microorganism-mediated alteration reactions of natural products in the sediments. Additional novel polyfunctional friedelane derivatives, namely friedelane-2,3-dione, friedelane-1,3-diol-2-one and friedel-1(10)-ene-1,3-diol-2-one were identified for the first time in this study. These novel polyfunctional triterpenoids were inferred to derive from the oxidation of the triterpenoids from higher plants in this oxic tropical environment. For future reference purposes, the mass spectra of the identified polar triterpenoids are also presented here. This study provides important data on the biogeochemistry of organic matter in a tropical lake of SE Asia.  相似文献   

Geochemical characteristics and hydrocarbon generation modeling of the Jurassic source rocks in the Shoushan Basin, north Western Desert, Egypt   总被引：1，自引：0，他引：1  

Mohamed Ragab ShalabyMohammed Hail Hakimi  Wan Hasiah Abdullah 《Marine and Petroleum Geology》2011,28(9):1611-1624

The Shoushan Basin is an important hydrocarbon province in the Western Desert, Egypt, but the origin of the hydrocarbons is not fully understood. In this study, organic matter content, type and maturity of the Jurassic source rocks exposed in the Shoushan Basin have been evaluated and integrated with the results of basin modeling to improve our understanding of burial history and timing of hydrocarbon generation. The Jurassic source rock succession comprises the Ras Qattara and Khatatba Formations, which are composed mainly of shales and sandstones with coal seams. The TOC contents are high and reached a maximum up to 50%. The TOC values of the Ras Qattara Formation range from 2 to 54 wt.%, while Khatatba Formation has TOC values in the range 1-47 wt.%. The Ras Qattara and Khatatba Formations have HI values ranging from 90 to 261 mgHC/gTOC, suggesting Types II-III and III kerogen. Vitrinite reflectance values range between 0.79 and 1.12 VRr %. Rock−Eval T_max values in the range 438-458 °C indicate a thermal maturity level sufficient for hydrocarbon generation. Thermal and burial history models indicate that the Jurassic source rocks entered the mature to late mature stage for hydrocarbon generation in the Late Cretaceous to Tertiary. Hydrocarbon generation began in the Late Cretaceous and maximum rates of oil with significant gas have been generated during the early Tertiary (Paleogene). The peak gas generation occurred during the late Tertiary (Neogene).  相似文献   

Establishment of Avicennia marina mangroves on accreting coastline at Sungai Haji Dorani, Selangor, Malaysia     

Noraini Mohd. Tamin  Rozainah Zakaria Roslan Hashim  Yu Yin 《Estuarine, Coastal and Shelf Science》2011,94(4):334-342

Avicennia marina saplings were established within a restoration area at Sg. Hj. Dorani, Malaysia between May and August 2010. Sapling establishment was achieved following the construction of segmented and hard breakwater as mitigating measure against coastal erosion. Geostructures known as brush faschines were installed within the restoration area as secondary sediment and seed traps. There was a steady increase in the sand content of the soil from 5% in November 2008 to 18% in May 2010. The dominant soil content was silt but it fluctuated and declined slightly over the same period, between 80% in November 2008 and 72% in May 2010. The accreting shoreline behind the breakwater had stabilised within 18 months. Subsequently, the first batch of A. marina wild seedlings or wildings was established on the mud surface in September 2009. Only about 10% of these wildings survived and showed high survival rate (90%) over the next eight months. Wildings that were naturally established near mother trees showed good growth performance. No wilding was established after the fruiting season in August 2010 as all seeds that were dispersed into the restoration area were washed away by September 2010. Tall, A. marina wild saplings (1 m) planted within the restoration area showed higher survival rate (80%) compared to planted saplings of Rhizophora apiculata (30%). Final planting of a thousand 1 m tall A. marina wild saplings was carried out from June 2010, in clumps of 20 and in 1 m × 1 m spacing. By the end of September 2010 clusters of regenerating A. marina mangroves about 1.5 m tall were successfully established on the accreting coastline.  相似文献   

Geochemical study of volcanic and associated granitic rocks from Endau Rompin, Johor, Peninsular Malaysia     

AZMAN A GHANI  ISMAIL YUSOFF  MEOR HAKIF AMIR HASSAN  ROSLI RAMLI 《Journal of Earth System Science》2013,122(1):65-78

  相似文献   

Hydrocarbon source potential and depositional environment of the Surma Group shales of Bengal basin,Bangladesh     

Md. Farhaduzzaman  Wan Hasiah Abdullah  Md. Aminul Islam 《Journal of the Geological Society of India》2014,83(4):433-446

Surma Group is the most important geological unit of Bengal basin, Bangladesh, because petroleum resources occur within this group. It is mainly composed of alternation of shale and sandstone and the shale fraction has long been considered as source rocks and the sandstone fraction as reservoir. These source and reservoir rocks have been studied by different authors by different approach but none of them adopted organic geochemistry and organic petrology as a means of study of source rock and their possible depositional environment. A total of thirty shale core samples have been collected from eight different gas fields to fulfill the short coming. The collected samples have been subjected to Source Rock Analysis (SRA) and/or Rock-Eval (RE) followed by pyrolysis gas chromatography (PyGC), gas chromatography mass spectrometry (GCMS), elemental analysis (EA) and organic petrological study such as vitrinite reflectance measurement and maceral analysis. The analyzed organic matter extracted from the shales of Surma Group consists mainly of Type III along with some Type II kerogen. The studied shales are mostly organically lean (TOC ±1%) and the extracted organic matter is fair to moderate. Based on these results, the analyzed shales have been ranked as poor (mostly) to fair quality source rock. The organic matter of the analyzed shale samples is thermally immature to early mature for hydrocarbon generation considering their T_max and measured mean vitrinite reflectance values. The hopane 22S/(22S + 22R), moretane/hopane ratio and sterane parameters are also in good agreement with these thermal maturity assessments. The predominance of odd carbons over even carbons (most common) and/or even carbons over odd carbon numbered n-alkanes, moderate Pr/Ph ratio, low to high Tm/Ts ratio, comparative abundance of sterane C₂₉ (i.e., C₂₉ >C₂₇>C₂₈), Pr/nC₁₇ — Ph/nC₁₈ values, C/S ratio and dominance of vitrinite macerals group with the presence of liptinite macerals demonstrate that the organic matter has derived mainly from terrestrial inputs with an insignificant contribution from the marine sources. The condition of deposition alternates from oxic to anoxic.  相似文献   

Adaptive neuro-fuzzy selection of the optimal parameters of protective spur dike     

Hossein Basser  Shahaboddin Shamshirband  Hojat Karami  Dalibor Petković  Shatirah Akib  Afshin Jahangirzadeh 《Natural Hazards》2014,73(3):1393-1404

This study proposes a new approach for determining optimum dimensions of protective spur dike to mitigate scour amount around existing spur dikes. The main objective of this article was to predict the most optimum values of the protective spur dikes to reach the best performance. To predict the protective spur dike parameters for scour controlling around spur dikes, this paper constructed a process which selects the optimal protective spur dike parameters in regard to actual length of the protective spur dike, actual length of the main spur dikes, distance between the protective spur dike and the first spur dike, angle between protective spur dike and flow direction, flow intensity and median size of bed sediments with adaptive neuro-fuzzy (ANFIS) method. To build a protective spur dike with the best features, it is desirable to select and analyze factors that are truly relevant or the most influential to the spur dike. This procedure is typically called variable selection, and it corresponds to finding a subset of the full set of recorded variables that exhibits good predictive abilities. In this study, architecture for modeling complex systems in function approximation and regression was used, based on using ANFIS. Variable searching using the ANFIS network was performed to determine how the five factors affect the protective spur dike. Experimental model of the protective spur dike was used to generate training and checking data for the ANFIS network.  相似文献   

Groundwater vulnerability assessment in the Melaka State of Malaysia using DRASTIC and GIS techniques   总被引：2，自引：0，他引：2  

S. M. Shirazi  H. M. Imran  S. Akib  Zulkifli Yusop  Z. B. Harun 《Environmental Earth Sciences》2013,70(5):2293-2304

The present work attempts to interpret the groundwater vulnerability of the Melaka State in peninsular Malaysia. The state of groundwater pollution in Melaka is a critical issue particularly in respect of the increasing population, and tourism industry as well as the agricultural, industrial and commercial development. Focusing on this issue, the study illustrates the groundwater vulnerability map for the Melaka State using the DRASTIC model together with remote sensing and geographic information system (GIS). The data which correspond to the seven parameters of the model were collected and converted into thematic maps by GIS. Seven thematic maps defining the depth to water level, net recharge, aquifer media, soil media, topography, impact of vadose zone and hydraulic conductivity were generated to develop the DRASTIC map. In addition, this map was integrated with a land use map for generating the risk map to assess the effect of land use activities on the groundwater vulnerability. Three types of vulnerability zones were assigned for both DRASTIC map and risk map, namely, high, moderate and low. The DRASTIC map illustrates that an area of 11.02 % is low vulnerability, 61.53 % moderate vulnerability and 23.45 % high vulnerability, whereas the risk map indicates that 14.40 % of the area is low vulnerability, 47.34 % moderate vulnerability and 38.26 % high vulnerability in the study area. The most vulnerability area exists around Melaka, Jasin and Alor Gajah cities of the Melaka State.  相似文献   

Evaluating freshwater lens morphology affected by seawater intrusion using chemistry-resistivity integrated technique: a case study of two different land covers in Carey Island, Malaysia   总被引：1，自引：1，他引：0  

M. F. Tajul Baharuddin  A. R. Othman  S. Taib  R. Hashim  M. H. Zainal Abidin  M. A. Radzuan 《Environmental Earth Sciences》2013,69(8):2779-2797

Freshwater lenses are vital to small island communities but are susceptible to seawater intrusion due to the physical changes in the shoreline land cover. The effect of seawater intrusion and irrigation water on a coastal unconfined aquifer beneath naturally preserved mangrove and deforested mangrove-barren belt was investigated in Carey Island. Analysis of the total dissolved solids (TDS) and earth resistivity (ER) using a geochemistry-electrical integrated technique gave a TDS–ER relationship capable of predicting freshwater lens morphology affected by sea-irrigation water. The study result shows freshwater was fourfold thicker in close proximity of the mangrove forest than the mangrove barren area; the further the shoreline from the mangrove thickest section, the less vulnerable was the seawater intrusion and the more fresh the irrigation water, and hence the greater the freshwater availability potential.  相似文献