The document discusses seismic interpretation work done on seismic lines 856-SGR-52 and 856-SGR-55 in the Sanghar area. The work included:
1) Marking seismic reflectors and identifying them using well data
2) Preparing average, mean and iso-velocity graphs
3) Making time and depth structure maps
4) Interpreting the subsurface structure including normal faults
5) Reverse modeling the seismic into impedance sections and correlating wells
The interpretation shows the area has a horst and graben structure formed by normal faulting during extensional tectonics. Anomalous zones detected on the impedance sections may indicate hydrocarbons.
Seismic Data Analysis and Structural Interpretation in Sanghar Area
1.
2.
3. To prepare graphs of average velocity, mean velocity
and Iso-velocity, to investigate the lateral and vertical
variation in velocity.
Marking and Identification of Seismic Horizons by
using well top data.
To prepare the Time Contour Map and Depth Contour
Map using K-tron X-Work and surfer and interpret the
subsurface structure.
To develop an understanding of tectonic, stratigraphic
and structural framework of the area.
4. To prepare two way Time contour maps, Depth contour and
Surface Maps using the lines 856-SGR-52,846-SGR-45,
856-SGR-55 and 856-SGR-62 of Basal Formation which is
a reservoir formation. For this purpose K-tron X-Work and
surfer softwares are used.
Reverse Modeling of Seismic section into Impedance
section using Advance surfer.
Correlation of four wells by Log plot software using well
tops data.
5. PART-I
STRUCTURAL AND STRATIGRAPHICAL
INTERPRETATION
PART-II
REVERSE MODELLING OF SEISMIC SECTION INTO
IMPEDANCE SECTION AND WELL CORRELATION
15. Lines 856-SGR-52 and 856-SGR-55
Area Sanghar
Orientation NW-SE
Nature Dip Line and Strike Line
Well on the Line Sachal and Barkat is near to
SGR-55 line
Energy Source Dynamite
S.P 101-667 and 101-1215
Number Of Folds 80 Folds
Company OGDCL
16. Reflectors marked 4Reflectors on both Sections
Faults 6 Normal faults on SGR-52
5 Normal faults on SGR-55
Major Structure Horst and Graben
18. To mark the reflectors.
To prepare the Average Velocity Graph Of the line
856-SGR-52 and 856-SGR-55.
To prepare the Mean Velocity Graph.
To prepare the Iso Velocity Map.
To prepare the Time and Depth Section of the line
856-SGR-52 and 856-SGR-55.
Time and Depth contour maps for identification of
Structure.
To Identify and name the Reflectors with the help
of Well tops of Bobi,Barkat,Sachal and Hartungu.
40. Following conclusion were deduced based on the current
studies:
The study area is dominated by Normal Faults.
The Normal faulting in the area shows that the area was
deformed by the extensional tectonic movement.
Since the area is under extension so horst & graben
structure is present in the study area.
From the structural and stratigraphic interpretation it is
concluded the structure formed in the area may act as a
favorable trap for the accumulation of hydrocarbons
41. REVERSE MODELLING OF SEISMIC SECTION INTO
IMPEDANCE SECTION
AND
WELL CORRELATION
42. INTERVAL VELOCITY
Vint = Z2-Z1/t2-t1
INSTANTANEOUS VELOCITY
Vinst = dZ/dt
ROOT-MEAN-SQUARE VELOCITY
Vrms=√ (sum of product of square of interval velocities and
time/sum of one way travel times)
STACKING VELOCITY
t=√t²○+x²/V²stack
56. Anomalous(Hydrocarbons)Zones can be detected with
help of impedance. In Sanghar Area similar zone has
been detected by P-Waves impedance that is confirmed
then by S-Waves impedance.
It can be studied further with the help of enhanced data
and advance approach.
57. It is a direct method to investigate depositional setting of
an area by correlating different stratigraphic
successions encountered in different wells
58. Using well tops data of four wells Bobi-01, Barkat-01,
Sachal-01 and Harthangu-01drilled at Sanghar area
lithologies are studied by using Log Plot Software. To
study the stratigraphic variations in an area usually wells
are correlated. In well correlation we observe the
thickness and depth of each strata.
59.
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PPL, Karachi, Pakistan.
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62. To all my faculty members but special Thanks to
Sir Anees Ahmed Bangash whose guidance
leads me to touch this stage