Horizon picking — g-Space
Horizon picking

Horizon picking software

Trace reflectors across a survey the way the data allows: fully manual where the section is difficult, interpolated where it is broken, tracked or autopicked where it is clean — on 2D lines, inline and crossline sections, arbitrary lines and inside the 3D scene, in time or in depth.

Download free trial See the picking modes Watch Demos
Five modes
Manual through multi-horizon autopick
Time or depth
2D, 3D and arbitrary lines
Live surface
The map updates as you pick
Crossline section in g-Space with several picked horizons, a fault and two wells, beside the contoured map of the current horizon
Interpreted horizon surface with well trajectories inside a 3D seismic view in g-Space
Three-dimensional horizon surface built from seismic picks in g-Space
In view
Picked horizons & their map
Horizon correlation is a loop, not a batch job. Pick on the section and the surface is rebuilt in the map view while you work, so a bad spread shows up immediately rather than after the run. The picks are a project object from the first click — the same horizon that the maps, the velocity model, the depth conversion and the mis-tie window all read — and g-Space keeps score as you go, reporting picking coverage along the line and counting the 180° phase jumps that betray a pick that has slipped onto the wrong loop.
Picking modes

Five ways to pick, chosen per section.

Mode is a setting in the Picking group of the Interpretation bar, not a different tool — so you drop from automatic to manual across a faulted block and back again without leaving the section.

Automatic
Autopicking

The default. The pick spreads out from your seed across the survey under the correlation and radius limits you set, and can be confined to a polygon so it stops at a boundary you draw.

Automatic, many
Autopicking — Multi-Horizon

Autopicks several horizons in a single pass, for a stratigraphic package that has to stay internally consistent rather than being traced one surface at a time.

Guided
Tracking

Follows the event across the section from the points you click, on amplitude and phase consistency — ideal where reflectors are well defined. Move to another section and Track horizon correlates it there.

Guided
Interpolation

You place key points and g-Space fills between them — the balance to strike where a reflector is partly obscured, cut by faults, or varies in continuity.

Manual
Continuous

Fully manual picking across the section, like drawing on the seismic image. What you fall back to in heavily faulted, folded or noisy ground where automation misreads the event.

AI
AI Horizons Stack

A wizard that picks several horizons across the seismic volume with a trained model. Its settings can be saved into a project workflow and re-run later instead of being executed on the spot.

Control

Automation you can argue with.

Every automatic pick is bounded by parameters you set on the bar: what the pick sits on, how it snaps, how similar a neighbouring trace has to be, and how far the spread is allowed to travel.

Phase correlation
Pick type puts the horizon on a zero phase, a peak or a trough, and the pick keeps that phase from trace to trace — the method that works where reflectors are clear and consistent.
Magnet and window
Magnet type decides how the pick snaps to the signal — by cross-correlation, for instance — inside a picking window and a cross-correlation window you set in milliseconds.
Correlation threshold
A percentage threshold and a choice of what the correlation is measured against decide when a candidate pick is good enough to keep, and when the spread should stop instead.
Radius and override
A radius limit caps how far from the seed the pick is accepted, and an override switch says whether picks already inside that radius are replaced or left alone.
Limit to a polygon
Point autopicking at a polygon and the spread stops at its boundary: bins outside are neither picked nor overwritten. It works together with the radius limit, so a bin has to satisfy both.
Time and depth together
Pick a time horizon on a depth section, or the reverse, and g-Space converts the pick through the current velocity model — so select one first, or the pick is not added.
Flatten & ghost view
Set a horizon as flatten to strip the structure out and read stratigraphy; capture a piece of one section, drag it — and rotate it — over another to carry a reflector across a fault block.
Move without the mouse
Arrow keys step the section up and down the scale, Ctrl with left and right walks the crosslines and Ctrl with up and down the inlines, while Page Up and Page Down move both at once.
Workflow

Six steps from a seed pick to a mapped surface.

1
Set the workspace up
A location map beside the sections you will pick on, synchronised so the active line, the intersection point and the wells stay in step across every view.
2
Start at the wells
Begin where the reflectors are tied to known formations by the well tie, so the surface you trace out is anchored to a marker rather than to a guess.
3
Create the horizon
Add it in the Data Manager, or straight on the section with the picking tool active, and set the phase, magnet, windows and limits before the first spread.
4
Pick and watch the map
Track, interpolate, draw or autopick as the section allows. The surface is rebuilt in the map view in real time, and coverage and phase-jump counts update live.
5
Repair the awkward parts
Delete a bad stretch by dragging over it with the right button and repick, ghost a neighbouring section over the gap, or flatten on a nearby horizon to read the sequence.
6
Turn it into a surface
Update the horizon map from the picks, compute dip and azimuth off it, build thickness maps against the neighbouring horizon, and pass it on to modelling and depth conversion.
Views & surfaces

What you pick on, and what you get.

Picking is done in the same views the rest of the interpretation uses, and the horizon it produces is a first-class project object rather than a file on the side.

Where picking happens
Every view that carries the Horizon picks tool
2D lines
A location map and a time or depth section side by side, the active profile highlighted, with one click to move to the next line.
Inline & crossline
3D sections in time or depth, stepped with the keyboard, with a perpendicular section created at the cursor on demand.
Arbitrary lines
A path you draw through the cube — along a structure, or through a set of wells — picked exactly as any other section.
3D scene
Pick by clicking any section in the 3D Time or 3D Depth view: a 2D line, an arbitrary line, an inline or crossline, or a face of the volume.
Slices
Time and depth slices for lateral continuity, with the current slice drawn as a draggable line on every section view.
On the section
Well trajectories, log curves, synthetic traces and markers drawn beside the reflectors, so the pick is made against the well control, not away from it.
What the horizon becomes
Downstream products of a picked surface
Its own map
Rebuilt from the current picks whenever you ask, and refreshed live in the map view while the picking runs.
Dip & azimuth
Maximum slope and slope direction computed straight off the surface and stored as horizon-attribute maps.
Thickness
One map per adjacent horizon pair — isochrons in the time domain, isochores and isopachs in depth.
Structure & velocity
The same surfaces drive map building, velocity modelling, depth conversion and the structural framework.
Correlation window
A horizon can centre the mis-tie analysis window, so cross-correlation between lines follows the structure instead of a fixed time gate.
Import & export
Binary, ASCII and Charisma in both directions, on the current datum and replacement velocity. Loading a binary set replaces every horizon, and asks first.
Tools in this group
The parts of g-Space this topic is built from
Interpretation bar Horizon picks AI Horizons Stack Seismic view 3D view Arbitrary lines Horizons Thickness & isopach maps Import / export horizons
More g-Space capabilities

Horizons are the spine of the interpretation.

The surfaces you pick here anchor the well ties, the fault framework, the velocity model and the reservoir grid. These are the other topics in the g-Space workflow.

g-Space overview Fault picking Well tie Seismic mis-tie Geological interpretation Petrophysics Velocity modeling Attribute analysis & AVO Geological modeling Reservoir characterization
FAQ

Questions, answered.

What picking modes does g-Space offer?
Five, chosen in the Picking group of the Interpretation bar. Tracking follows the event automatically from the points you click. Interpolation fills between key points you place yourself. Continuous is fully manual, like drawing on the section. Autopicking is the default and spreads the pick out across the survey, and Autopicking — Multi-Horizon does that for several horizons in one pass. There is also an AI Horizons Stack wizard that picks several horizons across the volume with a trained model.
Can horizons be picked in the depth domain and in 3D?
Yes. The same Horizon picks tool is on 2D lines, inline, crossline and arbitrary-line sections in both time and depth, and in the 3D Time and 3D Depth views, where you pick by clicking any section shown in the scene. When the horizon and the view are in different domains the pick is converted through the current velocity model, so a velocity model has to be selected first — without one the pick is not added.
How closely can automatic tracking be controlled?
Pick type sets the trace feature the pick sits on — zero phase, peak or trough — and Magnet type sets how it snaps to the signal, by cross-correlation for example. A picking window and a cross-correlation window in milliseconds, a correlation threshold in percent, the reference the correlation is measured against, a radius limit and an override-in-radius switch decide which candidate picks are accepted. Autopicking can also be confined to a polygon: the spread stops at its boundary and bins outside are neither picked nor overwritten.
What can a picked horizon be used for?
The picks become a horizon object in the Data Manager, and its map is rebuilt from them on demand — updating live in the map view while you pick. Dip and azimuth are computed straight off the surface as attribute maps, and adjacent horizon pairs produce thickness maps: isochrons in time, isochores and isopachs in depth. The same horizons drive map creation, velocity modelling and depth conversion, guide the mis-tie correlation window, and export as binary, ASCII or Charisma.
Get started

Pick your own survey and see the surface build.

Load a volume, seed a horizon and watch the map fill in as the pick spreads — take g-Space for a trial run, or talk to Geomage about a demo on your own data.

Download free trial See pricing