Indoor mapping exercise

Plotting information from seismic profiles on to a map

Seismic profiles are 2D images of the subsurface but the view they give can be compared to a rock outcrop such as a cliff

exposure in the field, only on a much bigger scale.

This exercise plots information from seismic profiles on to a map and is good practice for field mapping and visualizing structures in

3D.

Steps 1-4

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760.0780.0800.0820.0840.0860.0880.0900.0920.0940.0960.0980.01000.01020.01040.01060.01080.01100.01120.01140.01160.01180.01200.01220.01240.01260.01280.01300.01320.01340.01360.0- B92-40 -

1380.01400.01420.01440.01460.01480.01500.01520.01540.01560.01580.01600.01620.01640.01660.01680.01700.01720.01740.01760.01780.0SP:

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BP-84-195, 1330.85B90-37, 399.04

N

800 900 1000 1100 1200 1300 1400 1500 1600

600

800

1000

1200

400

200

0

TWT

(mse

c)

TWT (m

sec)

CMP

2 kmLine name: SSR-1

✂

Cut here

to 600msec

0

600

800

1000

1200

400

200

Mark the position of the hinge

1. Trace the line of each limb to see where they meet.

2. Measure the interlimb angle and mark the centre point.

Hinge for horizon A

3. The intersection of half the interlimb angle and the horizon is the hinge.

⁾∥ ⁾∥

0.200

0.300

0.400

0.500

0.600

0.700

0.800

0.900

1.000

1.100

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1.400

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0.300

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760.0780.0800.0820.0840.0860.0880.0900.0920.0940.0960.0980.01000.01020.01040.01060.01080.01100.01120.01140.01160.01180.01200.01220.01240.01260.01280.01300.01320.01340.01360.0- B92-40 -

1380.01400.01420.01440.01460.01480.01500.01520.01540.01560.01580.01600.01620.01640.01660.01680.01700.01720.01740.01760.01780.0SP:

0.200

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0.600

0.700

0.800

0.900

1.000

1.100

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1.400

BP-84-195, 1330.85B90-37, 399.04

N

800 900 1000 1100 1200 1300 1400 1500 1600

600

800

1000

1200

400

200

0

TWT

(mse

c)

TWT (m

sec)

CMP

2 kmLine name: SSR-1

✂

Cut here

to 600msec

0

600

800

1000

1200

400

200

Note the CMP position and TWT of the hinge

Hinge for horizon A

CMP positionof hinge

TWTof hinge

0.200

0.300

0.400

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0.600

0.700

0.800

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1.100

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1.400

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760.0780.0800.0820.0840.0860.0880.0900.0920.0940.0960.0980.01000.01020.01040.01060.01080.01100.01120.01140.01160.01180.01200.01220.01240.01260.01280.01300.01320.01340.01360.0- B92-40 -

1380.01400.01420.01440.01460.01480.01500.01520.01540.01560.01580.01600.01620.01640.01660.01680.01700.01720.01740.01760.01780.0SP:

0.200

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1.000

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BP-84-195, 1330.85B90-37, 399.04

N

800 900 1000 1100 1200 1300 1400 1500 1600

600

800

1000

1200

400

200

0

TWT

(mse

c)

TWT (m

sec)

CMP

2 kmLine name: SSR-1

✂

Cut here

to 600msec

0

600

800

1000

1200

400

200

Find the axial plane and note the CMP position at 0msec TWT

The axial plane divides the layer symmetrically and intersects the hinge.

Axial plane for horizon A

CMP positionof axial plane

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0.300

0.400

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1.100

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1024.01040.01060.01080.01100.01120.01140.01160.01180.01200.01220.01240.0- BP-84-195 -

1260.01280.01300.01320.01340.01360.01380.01400.01420.01428.0SP:

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1.000

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1.400

B92-40, 1129.21

600

800

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1200

400

200

0

600

800

1000

1200

400

200

0

1400130012001100 1150 1250 13501050

SE2 km

TWT

(mse

c)

TWT (m

sec)

CMP

✂

Cut here to

600msecLine name: SSR-2

Again find the position of the hinge

1. Trace the line of each limb to see where they meet.

2. Measure the interlimb angle and mark the centre point.

⁾∥ ⁾

∥ Hinge for horizon A

3. The intersection of half the interlimb angle and the horizon is the hinge.

0.200

0.300

0.400

0.500

0.600

0.700

0.800

0.900

1.000

1.100

1.200

1.300

1.400

0.200

0.300

0.400

0.500

0.600

0.700

0.800

0.900

1.000

1.100

1.200

1.300

1.400

1024.01040.01060.01080.01100.01120.01140.01160.01180.01200.01220.01240.0- BP-84-195 -

1260.01280.01300.01320.01340.01360.01380.01400.01420.01428.0SP:

0.200

0.300

0.400

0.500

0.600

0.700

0.800

0.900

1.000

1.100

1.200

1.300

1.400

B92-40, 1129.21

600

800

1000

1200

400

200

0

600

800

1000

1200

400

200

0

1400130012001100 1150 1250 13501050

SE2 km

TWT

(mse

c)

TWT (m

sec)

CMP

✂

Cut here to

600msecLine name: SSR-2

Hinge for horizon A

Note the CMP position and TWT of the hinge

CMP positionof hinge

TWTof hinge

0.200

0.300

0.400

0.500

0.600

0.700

0.800

0.900

1.000

1.100

1.200

1.300

1.400

0.200

0.300

0.400

0.500

0.600

0.700

0.800

0.900

1.000

1.100

1.200

1.300

1.400

1024.01040.01060.01080.01100.01120.01140.01160.01180.01200.01220.01240.0- BP-84-195 -

1260.01280.01300.01320.01340.01360.01380.01400.01420.01428.0SP:

0.200

0.300

0.400

0.500

0.600

0.700

0.800

0.900

1.000

1.100

1.200

1.300

1.400

B92-40, 1129.21

600

800

1000

1200

400

200

0

600

800

1000

1200

400

200

0

1400130012001100 1150 1250 13501050

SE2 km

TWT

(mse

c)

TWT (m

sec)

CMP

✂

Cut here to

600msecLine name: SSR-2

Hinge for horizon A

Finally add the axial plane and note the CMP position at 0msec TWT

Axial plane for horizon A

CMP positionof axial plane

Steps 5-6

Plot the position of the fold axial plane for each seismic profile on the map

Indoor mapping Basemap showing location of seismic profiles (basemap surface equivalent to 0ms TWT)

2 km

SSR-

2

SSR-

1

×

Position of axial plane for horizon A Position of axial

plane for horizon A

×

Note:The map surface is equivalent to 0msec TWT

Indoor mapping Basemap showing location of seismic profiles (basemap surface equivalent to 0ms TWT)

2 km

SSR-

2

SSR-

1

×

Position of axial plane for horizon A Position of axial

plane for horizon A

×

Note:The map surface is equivalent to 0msec TWT

Join the two points together to give the fold axial trace

Fold axial trace

Steps 7-10

Plot the position of the hinge for each seismic profile on the map

Indoor mapping Basemap showing location of seismic profiles (basemap surface equivalent to 0ms TWT)

2 km

SSR-

2

SSR-

1

Position of hinge for horizon A Position of hinge

for horizon A

Indoor mapping Basemap showing location of seismic profiles (basemap surface equivalent to 0ms TWT)

2 km

SSR-

2

SSR-

1

Overlay the TWT panel on the map to line up with the hinge positions

Indoor mapping Basemap showing location of seismic profiles (basemap surface equivalent to 0ms TWT)

2 km

SSR-

2

SSR-

1

Mark the intersection with SSR-1 and SSR-2

SSR-1

SSR-2

SSR-1SSR-2

××

SE

Plot the TWT of the hinge on the panel

SSR-1SSR-2

××

SE

Plunge measured as the angle from horizontal

Horizontal

⁽

Join the two points together, this will give the plunge