2D Seismic Reflection Data Interpretation(Part-I)

2D Seismic Reflection Data Interpretation
Imaging The Varied Lithology By Using Converted Shear Waves
(Lower Goru As A Case Study)

Objectives

1)   Dividing The Rocks Of The Area By Using Rock Physics

1)   Determining The Subsidence By Using Statistical Regression

2)   Stratigraphic Description Of The Lower Goru Formation By Using Rock Physics


GEOLOGY OF THE AREA

STRATIGRAPHY (Ahmed et al, 2004)
INTERPRETATION SCHEME

PART – I
Conversion Of Seismic Time Section To Depth Section

PART-II
Division Of Rock Types By Using Rock Physics As A Tool

PART-III
Determining The Subsidence By Using Statistical Regression

PART-IV
Stratigraphic Description Of Lower Goru Formation By Rock Physics

PART-V
The Hydrocarbon Zones And Rock Physics

PART-I

Conversion Of Seismic Time Section To Depth Section

BASEMAP
SEISMIC TIME SECTIONTime Section is the Developed Section of Reflectors Which Shows Subsurface Structure In Time Domain
AVERAGE VELOCITY GRAPH
Average Velocity Graph Shows the Variation Of Seismic Velocity With Time For Each CDP Of The Seismic Section
MEAN VELOCITY GRAPH

Average Velocity Graph Shows The Variation Of Velocity With Time Which Is The Mean Of All  CDP’s At The Same Time
DEPTH SECTION

Depth Section Has Been Prepared By The Conversion Of Time Section By Using The Method Of Mean Average. It Shows The Subsurface Structure In Depth Domain

INTERPRETATION

From Time Section And Depth Section We Can See That The Area Has Been Traversed By Normal Faults Forming Horst & Graben Structures. Somewhere step faults can be seen. This means that area has been operated by extensional forces and are more prominent near the boundary between Jacobabad-Khairpur High And Panno-Aqil Graben. Structural Traps May be present in the area provided if they are correlated with the Temperature Gradient.
PART-II
Division Of Rock Types By Using Rock Physics As A Tool

The Poisson’s Ratio

б = 0.5 * (Vp2 – 2 Vs2) / (Vp2 – Vs2)

Where
               б    =  Poisson’s Ratio
             Vp  =   P – Wave Velocity
             Vs  =   S  -- Wave Velocity


The Vp / Vs Ratio

Vp / Vs = SQRT (K / µ + 4 / 3)
Where
                         K =   Bulk Modulus
                         µ  =  Shear Modulus

The Bulk Modulus

K = ρ * (Vp2 - 4 / 3 Vs2)

Where
Vp = P – Wave Velocity
Vs  = S – Wave Velocity

The Shear Modulus

µ = ρ * Vs2

Where
                     ρ   = Density
            Vs = Shear Wave Velocity
Calculations For CDP 1256

 

posted by Geology on 06:22

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