What are the fields in Petrel's IESX seismic horizon file?

Question

I have a text file containing 23 seismic horizons from Petrel, Schlumberger's seismic earth interpretation and modelling tool, using the 2D IESX format. Here are the first few rows:

PROFILE Fault to seafloor    TYPE 1  5 By Petrel 2014.2 (64-bit)                2d_ci7m_gf.ifdf  m  ms
SNAPPING PARAMETERS 5     2 2
  4.19846879E+05  4.66812161E+06  1 14  2742.85   5460.00  16382.00 4262               2 276-109::normTOv
  4.19840089E+05  4.66813210E+06  1 14  2756.25   5461.00  16383.00 4263               2 276-109::normTOv
  4.19833299E+05  4.66814259E+06  1 14  2769.65   5461.00  16384.00 4264               2 276-109::normTOv
  4.19826509E+05  4.66815308E+06  1 14  2783.05   5461.00  16385.00 4265               2 276-109::normTOv
  4.19819720E+05  4.66816357E+06  1 14  2733.93   5462.00  16386.00 4266               2 276-109::normTOv
  4.19812930E+05  4.66817406E+06  1 14  2809.85   5462.00  16387.00 4267               2 276-109::normTOv
...

Each horizon starts with two similar header rows. I'm not too worried about those (but it would be nice to know about them too). I'm more interested in the (400,000 or so) data rows. Here's what I surmise so far:

1. (float) — x location
2. (float) — y location
3. [1-9] (int) — seems to change with each interpreted segment of horizon
4. 14 — no idea
5. (float) — two-way time
6. (float) — no idea
7. (float) — no idea
8. (int) — CDP or trace number
9. 2 — no idea
10. (str) — line::dataset

I have look at the application's documentation, to no avail. Does anyone know what the fields are?

Answer 1

1. X-coordinate
2. Y-coordinate
3. Segment number
4. Symbol code
5. Two-way time (ms)
6. Shot-point number
7. CDP number
8. Trace number
9. Line type (2=2D, I=inline, X=crossline)
10. 2D line name or 3D survey name

The format allows for a column between 8 and 9, for amplitude value — not present in this example.

This is a formatted layout to specific columns. So there is the potential for fields to butt against each other with no spaces between.

The top 2 lines define the horizon name (after PROFILE) and various picking parameters you shouldn't need.

This answer comes from Tom Cox (geoscientist at Schlumberger).

Answer 2

I think fields 6-7 are inline / crossline

Field 4 is some kind of internal IESX code... don't worry about it

I would've thought there was a seismic amplitude field somewhere... but it has been a long time!

Answer 3

Here is the official file

fdf_name="2d_ci7m_gf.ifdf";
fdf_description="2D Card Image 7 multi-horizon export (XY in meters)";
data_struct=header_data;
header_length=by_header;
sort_order=by_horizon;
num_header_cards=2;
begin_of_header_on=false;
end_of_header_on=false;
begin_of_data_on=false;
end_of_data_on=true;
end_of_data="EOD";
end_of_data_scol=1;
end_of_data_ecol=4;
end_of_data_pos=after_last_card;
profile_label_on=true;
profile_label="PROFILE";
profile_label_scol=1;
profile_label_ecol=7;
profile_label_cnum=1;
profile_name_on=true;
profile_name_scol=9;
profile_name_ecol=28;
profile_name_cnum=1;
profile_description_on=true;
profile_description_scol=40;
profile_description_ecol=79;
profile_description_cnum=1;
type_label_on=true;
type_label="TYPE";
type_label_scol=30;
type_label_ecol=33;
type_label_cnum=1;
profile_type_on=true;
profile_type_scol=35;
profile_type_ecol=35;
profile_type_cnum=1;
posting_color_on=true;
posting_color_scol=37;
posting_color_ecol=38;
posting_color_cnum=1;
contact_symbol_on=false;
line_label_on=false;
line_name_on=false;
line_number_on=false;
line_type_on=false;
survey_name_on=false;
snap_label_on=true;
snap_label="SNAPPING PARAMETERS";
snap_label_scol=1;
snap_label_ecol=19;
snap_label_cnum=2;
snap_position_on=true;
snap_position_scol=21;
snap_position_ecol=21;
snap_position_cnum=2;
snap_window_on=true;
snap_window_scol=23;
snap_window_ecol=27;
snap_window_cnum=2;
event_picked_on=true;
event_picked_scol=29;
event_picked_ecol=29;
event_picked_cnum=2;
format_file_name_on=true;
format_file_name_scol=81;
format_file_name_ecol=96;
format_file_name_cnum=1;
xy_units_on=true;
xy_units_scol=98;
xy_units_ecol=99;
xy_units_cnum=1;
z_units_on=true;
z_units_scol=101;
z_units_ecol=102;
z_units_cnum=1;
x_coordinate_on=true;
x_coordinate_scol=1;
x_coordinate_ecol=16;
x_coordinate_units=meter;
x_coordinate_type=exponent;
x_coordinate_decimal=8;
y_coordinate_on=true;
y_coordinate_scol=17;
y_coordinate_ecol=32;
y_coordinate_units=meter;
y_coordinate_type=exponent;
y_coordinate_decimal=8;
latitude_on=false;
longitude_on=false;
time_on=true;
time_scol=39;
time_ecol=47;
time_units=mili_second;
time_type=floating_points;
time_decimal=2;
seismic_trace_number_on=true;
seismic_trace_number_scol=68;
seismic_trace_number_ecol=72;
seismic_trace_number_type=integer;
seismic_trace_number_decimal=0;
shot_point_number_on=true;
shot_point_number_scol=48;
shot_point_number_ecol=57;
shot_point_number_type=floating_points;
shot_point_number_decimal=2;
cdp_on=true;
cdp_scol=58;
cdp_ecol=67;
cdp_type=floating_points;
cdp_decimal=2;
amplitude_on=true;
amplitude_scol=73;
amplitude_ecol=86;
amplitude_type=exponent;
amplitude_decimal=7;
attribute_1_on=false;
attribute_2_on=false;
attribute_3_on=false;
dat_profile_name_on=false;
dat_profile_type_on=false;
dat_line_name_on=true;
dat_line_name_scol=90;
dat_line_name_ecol=131;
dat_line_number_on=false;
dat_line_type_on=true;
dat_line_type_scol=88;
dat_line_type_ecol=89;
dat_survey_name_on=false;
dat_contact_symbol_on=true;
dat_contact_symbol_scol=36;
dat_contact_symbol_ecol=38;
dat_segment_id_on=true;
dat_segment_id_scol=33;
dat_segment_id_ecol=35;
dat_horizon_name_on=false;
dat_fault_name_on=true;
dat_fault_name_scol=132;
dat_fault_name_ecol=151;