This presentation summarizes the sedimentological analysis of sediments from well #XYZ in the Cambay Basin in India. Key points: 1. The Cambay Basin formed during the Mesozoic period and is segmented into five tectonic blocks. Sediments in the basin range from the Paleocene to recent. 2. Methodology included megascopic, petrographic, SEM, XRD studies, and core gamma ray logging to characterize the sediments. 3. Preliminary results identified sandstone, siltstone, and claystone lithologies. SEM analysis showed tight packing of grains in siltstone, reducing porosity. Gamma logs detected multiple sedimentation cycles.

1. A SUMMER TRAINING PRESENTATION ON
DETAILED SEDIMENTOLOGICAL ANALYSIS OF
SEDIMENTS FOR RESERVOIR CHARACTERISATION
OF WELL#XYZ, CAMBAY BASIN
Guided By
B K JHA
DGM ( Geology )
Submitted To:- Submitted By:-
DEPARTMENT OF PETROLEUM ENGINEERING HARI GOPAL SINGH
UNIVERSITY COLLEGE OF ENGINEERING 14/633
RAJASTHAN TECHNICAL UNIVERISTY KOTA (FINAL YEAR)

2. CONTETNTS
• INTRODUCTION
• STATIGRAPHY OF CAMBAY BASIN
• MATERIAL AND METHODOLOGY
1- MEGASCOPIC STUDIES
2- PETROGRAPHIC STUDIES
3- SCANNING ELECTRON MICROSCOPY
4- X-RAY DIFFRACTION STUDIES
5- CORE GAMMA RAY LOGGING
• SEDIMENTOLOGICAL LABORATORY STUDIES
• CONCLUSION
• REFERENCES

3. INTRODUCTION
• Cambay basin is situated at western flank of subcontinent formed at
the close of Mesozoic period by development of tensional faults
along its margins, accompanied by large scale volcanic activity was
further into four tectonic blocks , each with different degree of
tectonic intensity, controlled by basement faults.
• Cambay basin is segmented into five tectonic blocks :-
• Sanchor – patan block
Mehsana- Ahmedabad block
Tarapur – cambay block
Jambusar – broach block
Narmada – Tapti block

4. STRATIGRAPHY OF CAMBAY BASIN
• Palaeocene sediments are essentially
continental dumps and termed as olpad
formation.
• Olpad formation comprises grey calcareous
shale, siltstone and sandstone.
• Babguru formation overlies Tarapur shale.
Babaguru, kand, jhagadia, broach, jambusar
and Gujrat alluvium.

6. MATERIAL AND METHODOLOGY
1- MEGASCOPIC STUDIES:- The megascopic
studies are carried out with the help of binocular
stereo zoom microscope and include study of
lithofacies, texture, and other characteristics of
geological samples.
• Both the clastic and non- clastics core lithology
are graphically logged on graphic sheets, typically
depicting the measured length of core segment,
grain size variations, sedimentary structure and
bioturbation index.

7. 2- PETROGRAPHIC STUDIES:-
• Petrographic studies are carried out for clearly
interpretation of mineral identifications, grain size,
grain and matrix relationship, grain-cement
relation and source rock quality etc.
• Petrographic studies include preparation of thin
section of core sample and study by Optical
Microscope.

8. Petrological Microscope and view:-

9. 3- Scanning Electron Microscope (SEM):-
• Scanning electron microscope has been used for
studying the surface textures of sediments.
• SEM also including the determination of the origin
of depositional landforms, the provenance of
sediments, the energy of environments and
process of weathering, development through time.
• The resolution of SEM images is final product of a
comprises b/w contrast, depth of field, beam
diameter, voltage, magnifications, and host of
other operating conditions.

10. 4-X-RAY DIFFRACTION STUDIES(XRDs):-
• XRD is important for interpretation of the
mineralogical content of the sample.
• X-RAY Diffractometer is used for the investigation
of mineral in both qualitative and quantitative.
• Principal of working is that when a sample is
irradiated, the x- rays are diffracted in a way that
is characteristic of the compounds in the sample
under observation. By measuring the angle at
which intensity, the type and amount of
constituent compound can be determined.

12. 5-CORE GAMMA RAY LOGGING :-
• The objective of core gamma logging is to
correlate the cored depths from the extracted
cores with open hole wire line logs.
• Core gamma ray measures naturally occurring
gamma radiation in a rock. It capture three type
energy windows Potassium, Uranium, Thorium .
• Core gamma ray measure concentration of K(%),
Uranium (ppm), and Thorium (ppm).
• CGR also using for determination of shale
volume estimation and net pay thickness.

13. SEDIMENTOLOGICAL LABORATORY
STUDIES :-
• Sedimentological analysis of CC#1 (2043.0m-
2046m) and CC#2 (2046.4m-2055.40m) from
well#XYZ.

14. • T1 (16cm): Sandstone
• Segment T1 is sandstone which is light grey in
colour, moderately indurated, moderately hard &
compact and non calcareous in nature.

15. • SEM images of segment T14:-

16. • The SEM analysis of segment T2 bottom show
siltstone with poor reservoir characteristics
due to tight packing and presence of clay
minerals. Individual framework grains are
distinctly not visible. As such primary inter
granular porosity. Calcite minerals are present
in this segment.

17. CONCLUSION
• The sedimentological studies carried out on the rock
samples from the well include megascopic analysis,
petrographic analysis and SEM analysis and
electrologs recorded for the cored section.
• Textural study of the sediments indicate the mature
nature of the sediments in the studied sediments.
• The Gamma ray analysis of the Electrolog shows
presence of multiple sedimentation cycles. The low
gamma ray values indicate sandstone as lithology
whereas very low gamma values indicate clean sands.

18. THANK YOU.