Surfaces

Surfaces are geological or engineering horizons used to characterize reservoirs in three dimensions. In Tachapps, surfaces are used as inputs for reservoir models.

What is a Surface?

A surface is a 2D grid (or point cloud) that represents the depth or elevation of a geological boundary at each XY location. Common surface types include:

• Top Reservoir — The upper boundary of the producing formation
• Base Reservoir — The lower boundary
• Fluid Contact — Oil-water contact (OWC), gas-oil contact (GOC)
• Faults — Structural fault planes

Surface Formats

Tachapps supports the following surface file formats:

Format	Extension	Notes
Petrel ASCII Grid	.dat, .irap	Industry-standard grid format
ZMAP+ Grid	.dat	Supported via ZMAP parser
CSV Point Cloud	.csv	x, y, z columns required
GeoTIFF	.tif	Raster elevation grids

Uploading a Surface

1. Navigate to Project → Surfaces
2. Click Upload Surface
3. Select the file from your computer
4. Assign a name and type (top / base / contact / fault)
5. Set the coordinate reference system (CRS) if prompted
6. Click Upload

TIP

Large grids (>50 MB) are processed asynchronously. You will receive a notification when processing is complete.

Surface Metadata

{
  "id": "surface-001",
  "name": "Top Bone Spring",
  "type": "top_reservoir",
  "projectId": "proj-001",
  "crs": "EPSG:4326",
  "nodeCount": 125000,
  "zMin": -3200.5,
  "zMax": -2800.1,
  "uploadedAt": "2025-08-14T10:22:00Z"
}

Next Steps

• Data Sources →