An Advanced Well Log and an Effective Methodology to Evaluate Water Saturation of the Organic-Rich Cambay Shale     

De  Sanjukta  Sengupta  Debashish 《Natural Resources Research》2021,30(2):1719-1733

Water saturation (S_w) is a vital parameter in the evaluation of hydrocarbon reservoir. Realistic estimation of S_w in shale reservoir is a challenging problem because of the presence of significant clay minerals and organic matter. The present study aims to estimate S_w of organic-rich Cambay Shale, Jambusar–Broach block, Cambay Basin, India, using an effective methodology and improved equation (TOC–clay equation), considering the appropriate corrections to counter the effect of clay minerals and organic matter in modifying resistivity. Advanced log like Litho-scanner has been utilized for the continuous estimation of clay content and total organic carbon (TOC), required for the estimation of S_w. Elemental capture spectroscopy and support vector regression were also applied for evaluation of clay content and TOC in one well where Litho-scanner log is not available. To investigate the effectiveness and applicability of the TOC–clay equation, results of S_w estimated from this equation and various other models have been compared with core S_w for a well. The analysis indicates that S_w derived from TOC–clay equation is having the closest agreement to core S_w data with an average absolute percentage error of 7.9% and coefficient of correlation 0.95. For other models, average absolute errors are significantly higher (16.8–32.7%). The application of TOC–clay equation will be useful for evaluation of the Cambay Shale reservoir. In addition, the resistivity-based TOC–clay equation used in this study is simple with a practical approach; it can be applied easily and efficiently for any organic-rich shale reservoir elsewhere.

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Agent-Based Simulation of Urban Residential Dynamics and Land Rent Change in a Gentrifying Area of Boston     

Jeremy Jackson  Benjamin Forest  Raja Sengupta 《Transactions in GIS》2008,12(4):475-491

Certain complex processes are most effectively modeled not on the macro-scale, but from the bottom-up, by simulating the decisions of individual entities, or agents. This study uses an agent-based modeling (ABM) approach to simulate residential dynamics in an area of Boston that has increasingly experienced gentrification in the past decades. The model is instantiated using basic empirical data and uses simple decision-making rules, differentiated into four classes, to simulate the process of residential dynamics. The model employs the consumption explanation of the cause of gentrification, which emphasizes the choices of individuals drawn to urban amenities, while testing the production explanation, which suggests that major investments from the public and private sphere attract and explain gentrification. Verification shows that the processes in the model work according to its construction, simulates complexity and emergent phenomena, and may be a valuable explanatory tool for understanding and learning about some processes underlying gentrification.  相似文献   

Evidence of biodegradation of chlorpyrifos by a newly isolated heavy metal-tolerant bacterium <Emphasis Type="Italic">Acinetobacter</Emphasis> sp. strain MemCl4     

Santanu Pailan  Kriti Sengupta  Urmimala Ganguly  Pradipta Saha 《Environmental Earth Sciences》2016,75(12):1019

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Evidence of Superposed Metamorphism from the Gokavaram Area, Eastern Ghats Belt, and its Relation with the Kemp Land Coast, East Antarctica     

Somnath Dasgupta  Pulak Sengupta  Supratim Pal  Masato Fukuoka 《Gondwana Research》1999,2(2):227

In this paper, we compare the petrological histories of the Kemp Land Coast (east Antarctica), and Gokavaram area (Eastern Ghats), that were supposed to have been juxtaposed. The area around Gokavaram is dominated by different varieties of paragneisses (pelitic, quartzofeldspathic, and calcareous composition) with relatively minor amounts of orthogneisses (mafic, enderbitic, and granitic composition). The rocks were involved in three major phases of deformation, and were finally affected by localised shear movement. On the basis of reaction textures, well preserved in high Mg-Al granulites, and calc-silicate granulites, and geothermobarometric data we deduce a polymetamorphic evolution of the rocks. Following an early M₁ metamorphism culminating at 9.2–9.4 kbar, > 950°C, the rocks cooled nearly isobarically down to 850°C. During a subsequent M₂ metamorphism, near isothermal decompression to 5–6 kbar occurred. This was followed by near isobaric cooling down to 600–650°C. M₃ is a weak amphibolite facies overprint, largely restricted to late shears, which involved hydration as well. Available radiometric data from this area can be interpreted in terms of partial resetting of U-Pb systematics in older sphenes due to M₃ metamorphism at ca. 550 Ma. Despite the absence of sufficient isotopic data on the Eastern Ghats granulites, we document a remarkable similarity in the petrological history of the two supposedly erstwhile neighbours.  相似文献   

Changes In The Stream Courses Around Maithon Reservoir, Eastern India: Observations Using Remote Sensing Data     

S. Sengupta  A. Chatterjee 《Journal of the Indian Society of Remote Sensing》2000,28(4):277-280

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Did the Harappan settlement of Dholavira (India) collapse during the onset of Meghalayan stage drought?     

Torsa Sengupta  Arati Deshpande Mukherjee  Ravi Bhushan  F. Ram  M. K. Bera  Harsh Raj  Ankur J. Dabhi  R. S. Bisht  Y. S. Rawat  S. K. Bhattacharya  Navin Juyal  Anindya Sarkar 《第四纪科学杂志》2020,35(3):382-395

Radiocarbon dating of archaeological carbonates from seven cultural stages of Dholavira, Great Rann of Kachchh (GRK), the largest excavated Harappan settlement in India, suggests the beginning of occupation at ~5500 years BP (pre-Harappan), and continuation until ~3800 years BP (early part of the Late Harappan period). The settlement rapidly expanded under favourable monsoonal climate conditions when architectural elements such as the Citadel, Bailey, Lower and Middle Town were added between the Early and mid-Mature Harappan periods. Abundant local mangroves grew around the GRK sustaining prolific populations of the edible gastropod Terebralia palustris. Oxygen isotope (δ¹⁸O) sclerochronology of Early Harappan gastropod shell suggests seasonal mixing of some depleted (δ¹⁸O ~ −12‰) river water in summer/monsoon months (through ancient Saraswati and/or Indus distributary channels) with seawater that periodically inundated the GRK. Evaporation from this semi-enclosed water body during the non-monsoon months enriched the δ¹⁸O of water/shell carbonates. The humid fluvial landscape possibly changed due to a catastrophic drought driving the final collapse of the settlement of Dholavira exactly at the onset of the Meghalayan (Late Holocene) stage (~4300–4100 years BP ). Indeed, Dholavira presents a classic case for understanding how climate change can increase future drought risk as predicted by the IPCC working group. Copyright © 2019 John Wiley & Sons, Ltd.  相似文献   

Microstructural Variation in Quartzofeldspathic Mylonites: Example from Schirmacher Hills, East Antarctica     

Santanu Bose  Sudipta Sengupta 《Gondwana Research》2001,4(4):581-582

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Statistical Correlation between Iron (Fe) and Arsenic (As) and Probabilities of their Conjugate Occurrences in Groundwater from two Different Areas of West Bengal (southern part), India     

B.J. Sengupta  Sudipto Lahiri 《Journal of the Geological Society of India》2018,92(3):378-378

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H i imaging of galaxies in X-ray bright groups     

Chandreyee Sengupta †  Ramesh Balasubramanyam  K. S. Dwarakanath 《Monthly notices of the Royal Astronomical Society》2007,378(1):137-147

Environment plays an important role in the evolution of the gas contents of galaxies. Gas deficiency of cluster spirals and the role of the hot intracluster medium in stripping gas from these galaxies is a well-studied subject. Loose groups with diffuse X-ray emission from the intragroup medium (IGM) offer an intermediate environment between clusters and groups without a hot IGM. These X-ray bright groups have smaller velocity dispersion and lower temperature than clusters, but higher IGM density than loose groups without diffuse X-ray emission. A single-dish comparative study of loose groups with and without diffuse X-ray emission from the IGM, showed that the galaxies in X-ray bright groups have lost more gas on average than the galaxies in non X-ray bright groups. In this paper we present GMRT H  i observations of 13 galaxies from four X-ray bright groups: NGC 5044, 720, 1550 and IC1459. The aim of this work is to study the morphology of H  i in these galaxies and to see if the hot IGM has in any way affected their H  i content or distribution. In addition to disturbed H  i morphology, we find that most galaxies have shrunken H  i discs compared to the field spirals. This indicates that IGM-assisted stripping processes like ram pressure may have stripped gas from the outer edges of the galaxies.  相似文献   

Identification and mapping of chromium (VI) plume in groundwater for remediation: A case study at Kanpur,Uttar Pradesh   总被引：1，自引：0，他引：1  

R. K. Singh  B. Sengupta  Rameshwar Bali  B. P. Shukla  V. V. S. Gurunadharao  Rajesh Srivatstava 《Journal of the Geological Society of India》2009,74(1):49-57

With only twenty five percent population living in urban areas, India has cities amongst the biggest in the world. Urban growth in most of Indian cities is concomitant with rise in water demand for community, as well as, for industrial purposes. The complex situation resulting from indiscriminate disposal of waste and its severe impact on groundwater quality is set for continuous worsening mainly for want of sustained effort aimed at site-specific remediation. The study, a prerequisite for actual remediation in an industrial city of Kanpur, India, envisages detailed investigation about pollutant transport, evaluation of concept of Bio-remediation and a range of other options and finally full scale implementation of the best suited. Drilling of piezometers and resistivity survey indicates that the area is constituted of alluvial sands, gravels and their various admixtures. Chemical analysis of water samples collected from piezometers and hand pumps shows the presence of hexavalent chromium rich horizons at various depths. The alarming concentration of this carcinogenic heavy metal of the order of 16.3 mg/l against the permissible concentration (of 0.05 mg/l) for drinking water and high concentration within sediments of the area poses a major threat to the entire ecosystem. The projection of migration contaminant plume of hexavalent chromium as depicted in the paper is indicative of a concentrated extent of core zone existing in shallow alluvial aquifer, which may be targeted for interception by remedial measures. The present work, elaborating on the source, potential and monitoring the migration of the pollutant plume is the first field scale study of its kind in the country. The findings of these studies are of strong relevance in addressing the ground water pollution due to indiscriminate disposal practices of hazardous waste in areas located within the alluvial zones.  相似文献