Extract data at the intersection of a horizon and 3D volume¶

In [2]:

import matplotlib.pyplot as plt
import xarray as xr

%matplotlib inline

from segysak.segy import (
    get_segy_texthead,
    segy_header_scan,
    segy_header_scrape,
)

from os import path

import matplotlib.pyplot as plt import xarray as xr %matplotlib inline from segysak.segy import ( get_segy_texthead, segy_header_scan, segy_header_scrape, ) from os import path

Load Small 3D Volume from Volve¶

In [3]:

volve_3d_path = path.join("data", "volve10r12-full-twt-sub3d.sgy")
print("3D", volve_3d_path, path.exists(volve_3d_path))

volve_3d_path = path.join("data", "volve10r12-full-twt-sub3d.sgy") print("3D", volve_3d_path, path.exists(volve_3d_path))

3D data/volve10r12-full-twt-sub3d.sgy True

In [4]:

get_segy_texthead(volve_3d_path)

get_segy_texthead(volve_3d_path)

Out[4]:

Text Header

C 1 SEGY OUTPUT FROM Petrel 2017.2 Saturday, June 06 2020 10:15:00
C 2 Name: ST10010ZDC12-PZ-PSDM-KIRCH-FULL-T.MIG_FIN.POST_STACK.3D.JS-017534 ÝCro
C 3
C 4 First inline: 10090 Last inline: 10150
C 5 First xline: 2150 Last xline: 2351
C 6 CRS: ED50-UTM31 ("MENTOR:ED50-UTM31:European 1950 Based UTM, Zone 31 North,
C 7 X min: 433955.09 max: 436589.56 delta: 2634.47
C 8 Y min: 6477439.46 max: 6478790.23 delta: 1350.77
C 9 Time min: -3402.00 max: -2.00 delta: 3400.00
C10 Lat min: 58.25'52.8804"N max: 58.26'37.9493"N delta: 0.00'45.0689"
C11 Long min: 1.52'7.1906"E max: 1.54'50.9616"E delta: 0.02'43.7710"
C12 Trace min: -3400.00 max: -4.00 delta: 3396.00
C13 Seismic (template) min: -58.55 max: 54.55 delta: 113.10
C14 Amplitude (data) min: -58.55 max: 54.55 delta: 113.10
C15 Trace sample format: IEEE floating point
C16 Coordinate scale factor: 100.00000
C17
C18 Binary header locations:
C19 Sample interval : bytes 17-18
C20 Number of samples per trace : bytes 21-22
C21 Trace date format : bytes 25-26
C22
C23 Trace header locations:
C24 Inline number : bytes 5-8
C25 Xline number : bytes 21-24
C26 Coordinate scale factor : bytes 71-72
C27 X coordinate : bytes 73-76
C28 Y coordinate : bytes 77-80
C29 Trace start time/depth : bytes 109-110
C30 Number of samples per trace : bytes 115-116
C31 Sample interval : bytes 117-118
C32
C33
C34
C35
C36
C37
C38
C39
C40 END EBCDIC

In [5]:

volve_3d = xr.open_dataset(
    volve_3d_path,
    dim_byte_fields={"iline": 5, "xline": 21},
    extra_byte_fields={"cdp_x": 73, "cdp_y": 77},
)
volve_3d.segysak.scale_coords()
volve_3d.data

volve_3d = xr.open_dataset( volve_3d_path, dim_byte_fields={"iline": 5, "xline": 21}, extra_byte_fields={"cdp_x": 73, "cdp_y": 77}, ) volve_3d.segysak.scale_coords() volve_3d.data

Out[5]:

<xarray.DataArray 'data' (iline: 61, xline: 202, samples: 850)> Size: 42MB
[10473700 values with dtype=float32]
Coordinates:
  * iline    (iline) int16 122B 10090 10091 10092 10093 ... 10148 10149 10150
  * xline    (xline) int16 404B 2150 2151 2152 2153 2154 ... 2348 2349 2350 2351
  * samples  (samples) float32 3kB 4.0 8.0 12.0 ... 3.392e+03 3.396e+03 3.4e+03
Attributes:
    seisnc:   {"source_file": "data/volve10r12-full-twt-sub3d.sgy", "measurem...
    text:     C 1 SEGY OUTPUT FROM Petrel 2017.2 Saturday, June 06 2020 10:15...

xarray.DataArray

'data'

• iline: 61
• xline: 202
• samples: 850

• ...

  [10473700 values with dtype=float32]

• Coordinates: (3)
  • iline
    (iline)
    int16
    10090 10091 10092 ... 10149 10150

    array([10090, 10091, 10092, 10093, 10094, 10095, 10096, 10097, 10098, 10099,
           10100, 10101, 10102, 10103, 10104, 10105, 10106, 10107, 10108, 10109,
           10110, 10111, 10112, 10113, 10114, 10115, 10116, 10117, 10118, 10119,
           10120, 10121, 10122, 10123, 10124, 10125, 10126, 10127, 10128, 10129,
           10130, 10131, 10132, 10133, 10134, 10135, 10136, 10137, 10138, 10139,
           10140, 10141, 10142, 10143, 10144, 10145, 10146, 10147, 10148, 10149,
           10150], dtype=int16)

  • xline
    (xline)
    int16
    2150 2151 2152 ... 2349 2350 2351

    array([2150, 2151, 2152, ..., 2349, 2350, 2351], dtype=int16)

  • samples
    (samples)
    float32
    4.0 8.0 12.0 ... 3.396e+03 3.4e+03

    array([   4.,    8.,   12., ..., 3392., 3396., 3400.], dtype=float32)

• Indexes: (3)
  • iline
    PandasIndex

    PandasIndex(Index([10090, 10091, 10092, 10093, 10094, 10095, 10096, 10097, 10098, 10099,
           10100, 10101, 10102, 10103, 10104, 10105, 10106, 10107, 10108, 10109,
           10110, 10111, 10112, 10113, 10114, 10115, 10116, 10117, 10118, 10119,
           10120, 10121, 10122, 10123, 10124, 10125, 10126, 10127, 10128, 10129,
           10130, 10131, 10132, 10133, 10134, 10135, 10136, 10137, 10138, 10139,
           10140, 10141, 10142, 10143, 10144, 10145, 10146, 10147, 10148, 10149,
           10150],
          dtype='int16', name='iline'))

  • xline
    PandasIndex

    PandasIndex(Index([2150, 2151, 2152, 2153, 2154, 2155, 2156, 2157, 2158, 2159,
           ...
           2342, 2343, 2344, 2345, 2346, 2347, 2348, 2349, 2350, 2351],
          dtype='int16', name='xline', length=202))

  • samples
    PandasIndex

    PandasIndex(Index([   4.0,    8.0,   12.0,   16.0,   20.0,   24.0,   28.0,   32.0,   36.0,
             40.0,
           ...
           3364.0, 3368.0, 3372.0, 3376.0, 3380.0, 3384.0, 3388.0, 3392.0, 3396.0,
           3400.0],
          dtype='float32', name='samples', length=850))

• Attributes: (2)

  seisnc :

  {"source_file": "data/volve10r12-full-twt-sub3d.sgy", "measurement_system": "m", "sample_rate": 4.0}

  text :

  C 1 SEGY OUTPUT FROM Petrel 2017.2 Saturday, June 06 2020 10:15:00 C 2 Name: ST10010ZDC12-PZ-PSDM-KIRCH-FULL-T.MIG_FIN.POST_STACK.3D.JS-017534 ÝCro C 3 C 4 First inline: 10090 Last inline: 10150 C 5 First xline: 2150 Last xline: 2351 C 6 CRS: ED50-UTM31 ("MENTOR:ED50-UTM31:European 1950 Based UTM, Zone 31 North, C 7 X min: 433955.09 max: 436589.56 delta: 2634.47 C 8 Y min: 6477439.46 max: 6478790.23 delta: 1350.77 C 9 Time min: -3402.00 max: -2.00 delta: 3400.00 C10 Lat min: 58.25'52.8804"N max: 58.26'37.9493"N delta: 0.00'45.0689" C11 Long min: 1.52'7.1906"E max: 1.54'50.9616"E delta: 0.02'43.7710" C12 Trace min: -3400.00 max: -4.00 delta: 3396.00 C13 Seismic (template) min: -58.55 max: 54.55 delta: 113.10 C14 Amplitude (data) min: -58.55 max: 54.55 delta: 113.10 C15 Trace sample format: IEEE floating point C16 Coordinate scale factor: 100.00000 C17 C18 Binary header locations: C19 Sample interval : bytes 17-18 C20 Number of samples per trace : bytes 21-22 C21 Trace date format : bytes 25-26 C22 C23 Trace header locations: C24 Inline number : bytes 5-8 C25 Xline number : bytes 21-24 C26 Coordinate scale factor : bytes 71-72 C27 X coordinate : bytes 73-76 C28 Y coordinate : bytes 77-80 C29 Trace start time/depth : bytes 109-110 C30 Number of samples per trace : bytes 115-116 C31 Sample interval : bytes 117-118 C32 C33 C34 C35 C36 C37 C38 C39 C40 END EBCDIC

Load up horizon data¶

In [6]:

top_hugin_path = path.join("data", "hor_twt_hugin_fm_top.dat")
print("Top Hugin", top_hugin_path, path.exists(top_hugin_path))

top_hugin_path = path.join("data", "hor_twt_hugin_fm_top.dat") print("Top Hugin", top_hugin_path, path.exists(top_hugin_path))

Top Hugin data/hor_twt_hugin_fm_top.dat True

In [7]:

import pandas as pd

top_hugin_df = pd.read_csv(top_hugin_path, names=["cdp_x", "cdp_y", "samples"], sep=" ")
top_hugin_df.head()

import pandas as pd top_hugin_df = pd.read_csv(top_hugin_path, names=["cdp_x", "cdp_y", "samples"], sep=" ") top_hugin_df.head()

Out[7]:

	cdp_x	cdp_y	samples
0	432186.713151	6.477029e+06	2776.275147
1	432189.737524	6.477041e+06	2779.657715
2	432192.761898	6.477053e+06	2780.465088
3	432195.786271	6.477066e+06	2780.949951
4	432198.810645	6.477078e+06	2781.769775

Would be good to plot a seismic (iline,xline) section in Pyvista as well

In [8]:

# import pyvista as pv

# point_cloud = pv.PolyData(-1*top_hugin_df.to_numpy(), cmap='viridis')
# point_cloud.plot(eye_dome_lighting=True)

# import pyvista as pv # point_cloud = pv.PolyData(-1*top_hugin_df.to_numpy(), cmap='viridis') # point_cloud.plot(eye_dome_lighting=True)

Alternativey we can use the points to output a xarray.Dataset which comes with coordinates for plotting already gridded up for Pyvista.

In [9]:

top_hugin_ds = volve_3d.seis.surface_from_points(
    top_hugin_df, "samples", right=("cdp_x", "cdp_y")
)
top_hugin_ds

top_hugin_ds = volve_3d.seis.surface_from_points( top_hugin_df, "samples", right=("cdp_x", "cdp_y") ) top_hugin_ds

Out[9]:

<xarray.Dataset> Size: 99kB
Dimensions:  (iline: 61, xline: 202)
Coordinates:
  * iline    (iline) int16 122B 10090 10091 10092 10093 ... 10148 10149 10150
  * xline    (xline) int16 404B 2150 2151 2152 2153 2154 ... 2348 2349 2350 2351
    samples  (iline, xline) float64 99kB 2.741e+03 2.742e+03 ... 2.635e+03
Data variables:
    *empty*
Attributes:
    seisnc:   {"coord_scalar": -100.0, "coord_scaled": true}

xarray.Dataset

• Dimensions:
  • iline: 61
  • xline: 202
• Coordinates: (3)
  • iline
    (iline)
    int16
    10090 10091 10092 ... 10149 10150

    array([10090, 10091, 10092, 10093, 10094, 10095, 10096, 10097, 10098, 10099,
           10100, 10101, 10102, 10103, 10104, 10105, 10106, 10107, 10108, 10109,
           10110, 10111, 10112, 10113, 10114, 10115, 10116, 10117, 10118, 10119,
           10120, 10121, 10122, 10123, 10124, 10125, 10126, 10127, 10128, 10129,
           10130, 10131, 10132, 10133, 10134, 10135, 10136, 10137, 10138, 10139,
           10140, 10141, 10142, 10143, 10144, 10145, 10146, 10147, 10148, 10149,
           10150], dtype=int16)

  • xline
    (xline)
    int16
    2150 2151 2152 ... 2349 2350 2351

    array([2150, 2151, 2152, ..., 2349, 2350, 2351], dtype=int16)

  • samples
    (iline, xline)
    float64
    2.741e+03 2.742e+03 ... 2.635e+03

    array([[2740.59485122, 2742.24524139, 2743.93300054, ..., 2595.47726491,
            2595.96933417, 2596.44448208],
           [2741.6191921 , 2743.0088903 , 2744.83246656, ..., 2595.38667951,
            2595.8743274 , 2596.34089321],
           [2742.10649676, 2743.93585433, 2745.54148252, ..., 2595.35977674,
            2595.85903865, 2596.33157239],
           ...,
           [2796.93456887, 2796.92284985, 2796.97657312, ..., 2629.01956717,
            2630.53165788, 2632.67245508],
           [2796.98192079, 2796.95385786, 2796.95774686, ..., 2629.63486248,
            2631.2087454 , 2633.7785019 ],
           [2796.99194158, 2796.92309694, 2796.89424697, ..., 2630.07582204,
            2631.81238694, 2634.64023552]])

• Data variables: (0)
• Indexes: (2)
  • iline
    PandasIndex

    PandasIndex(Index([10090, 10091, 10092, 10093, 10094, 10095, 10096, 10097, 10098, 10099,
           10100, 10101, 10102, 10103, 10104, 10105, 10106, 10107, 10108, 10109,
           10110, 10111, 10112, 10113, 10114, 10115, 10116, 10117, 10118, 10119,
           10120, 10121, 10122, 10123, 10124, 10125, 10126, 10127, 10128, 10129,
           10130, 10131, 10132, 10133, 10134, 10135, 10136, 10137, 10138, 10139,
           10140, 10141, 10142, 10143, 10144, 10145, 10146, 10147, 10148, 10149,
           10150],
          dtype='int16', name='iline'))

  • xline
    PandasIndex

    PandasIndex(Index([2150, 2151, 2152, 2153, 2154, 2155, 2156, 2157, 2158, 2159,
           ...
           2342, 2343, 2344, 2345, 2346, 2347, 2348, 2349, 2350, 2351],
          dtype='int16', name='xline', length=202))

• Attributes: (1)

  seisnc :

  {"coord_scalar": -100.0, "coord_scaled": true}

In [10]:

# the twt values from the points now in a form we can relate to the xarray cube.
plt.imshow(top_hugin_ds.samples)

# the twt values from the points now in a form we can relate to the xarray cube. plt.imshow(top_hugin_ds.samples)

Out[10]:

<matplotlib.image.AxesImage at 0x7fcec92aeb60>

In [11]:

# point_cloud = pv.StructuredGrid(
#     top_hugin_ds.cdp_x.values,
#     top_hugin_ds.cdp_y.values,top_hugin_ds.twt.values,
#     cmap='viridis')
# point_cloud.plot(eye_dome_lighting=True)

# point_cloud = pv.StructuredGrid( # top_hugin_ds.cdp_x.values, # top_hugin_ds.cdp_y.values,top_hugin_ds.twt.values, # cmap='viridis') # point_cloud.plot(eye_dome_lighting=True)

Horizon Amplitude Extraction¶

Extracting horizon amplitudes requires us to interpolate the cube onto the 3D horizon.

In [12]:

top_hugin_amp = volve_3d.data.interp(
    {"iline": top_hugin_ds.iline, "xline": top_hugin_ds.xline, "samples": top_hugin_ds.samples}
)

top_hugin_amp = volve_3d.data.interp( {"iline": top_hugin_ds.iline, "xline": top_hugin_ds.xline, "samples": top_hugin_ds.samples} )

In [13]:

#
fig = plt.figure(figsize=(15, 5))
top_hugin_amp.plot(cmap="bwr")
cs = plt.contour(
    top_hugin_amp.xline, top_hugin_amp.iline, top_hugin_ds.samples, levels=20, colors="grey"
)
plt.clabel(cs, fontsize=14, fmt="%.1f")

# fig = plt.figure(figsize=(15, 5)) top_hugin_amp.plot(cmap="bwr") cs = plt.contour( top_hugin_amp.xline, top_hugin_amp.iline, top_hugin_ds.samples, levels=20, colors="grey" ) plt.clabel(cs, fontsize=14, fmt="%.1f")

Out[13]:

<a list of 24 text.Text objects>