Journal of Geological Society of India (Online archive from Vol 1 to Vol 78)

D. Hossain ¹, R. K. Majumder ²

Affiliations
1 Department of Geological Sciences, Jahangirnagar University, Savar, Dhaka-1342, BD
2 Grant Geophysical Inc., Party No. 432, Chittagong, BD

Abstract

The available geophysical well logs from the eastern part of Dhaka City have been interpreted to ascertain aquifer properties and to infer groundwater quality. From the interpretation of geophysical logs and study of the borelogs, the subsurface materials of the area could be divided into three litho-units; the upper and lower clay units, and the middle sand unit, i.e., the aquifer. These units appear to be characterized by contrasting physical properties and in particular, the resistivity. The anisotropy in electrical resistivity of the layered formation has also been examined. While the clay units are practically isotropic, the sand unit seems to be anisotropic and that may be principally related to variation in lithology. The percentage volume of shale, porosity, specific yield, and specific retention of the aquifer have been evaluated. The water quality parameters reveal complete potability of the groundwater.

Keywords

Hydrogeology, Groundwater, Geophysical Well Logs, Coefficient of Anisotropy, Aquifer Parameters, Dhaka City, Bangladesh.

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D. Hossain ¹

Affiliations
1 Department of Geological Sciences, Jahangirnagar Univerhity, Savar, Dhaka, BD

Abstract

An analysis of the available seismic data from the Rashidpur anticlinal structure in the Surma basin, Bangladesh, shows that there are only a few interfaces that may generate significant reflections (medium category reflectors) down to the depth of four km, while the rest correspond to the category of weak reflectors. The relative amplitudes of different types of multiple events reveal that only 1^st order surface multiples and peg leg multiples may possess amplitudes that can be detected on a seismogram. It has been concluded that the application of common-depth-point (CDP) shooting in the Surma basin should be directed towards not only enhancing signal-to-noise ratio (SNR), but also obtaining precise seismic velocity information.

Keywords

Solid Earth Geophysics, Reflection Seismology, Rashidpur Structure, Common-Depth-Point Shooting, Stacking Chart, Surma Basin, Bangladesh.

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N. Lakshmi Narayana ¹, D. Hossain , R. K. Majumder

Affiliations
1 Geohouse, Plot No.32/B, Road no.2, Adarsh Nagar, Nagole, Hyderabad - 500 068, IN

Abstract

No Abstract.

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Kazi Ariful Islam ¹, D. Hossain ¹

Affiliations
1 Department of Geological Sciences, Jahangirnagar University, Savar, Dhaka- 1342, BD

Abstract

The Kailastila structure is located in eastern part of the Surma basin in the Bengal foredeep. This paper presents the results of interpretation of seismic and oil well data for this structure. Three prominent reflection bands are observed on seismic sections. Based on the analyses of seismic sections (31 nos.) and correlation with the well data, eight prominent reflecting horizons and five prospective sand layers could be identified. Structural analysis shows that the Kailastila is an asymmetric anticline with NNE axial trend whose western flank is steeper and affected by a thrust fault with SW-NE trend. A saddle has been interpreted at about 4 km in N-NE direction from the crest. To the north of the saddle, a structural high has been delineated, which is closed by a normal fault running SW-NE. Reflection amplitude has been analyzed. The gas producing sands of the Kailastila structure belong to the Bokabil to Bhuban Formations of Miocene age. The seismic-stratigraphy and well data of the Kailastila area show up distinctly all the formations in the section.

Keywords

Seismic Data, Seismic Stratigraphy, Lithostratigraphy, Kailastila Structure, Surma Basin, Bangladesh.

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