# Well

> The .well open format — a JSON standard for water well data. Depths in meters, diameters in millimeters, measured from ground level.

The root object of a .well file. [Defined in the spec](/format/spec/v2/format-reference#top-level-structure). Blocks link to their own page.

| Field | Type | Required | Values / constraints | Description |
| --- | --- | --- | --- | --- |
| `version` | integer \| string | yes | integer: >= 0; string: pattern `^\d+\.\d+$` |  |
| `@context` | string \| any[] \| object | no |  |  |
| `well_id` | [WellId](/format/reference/objects/well-id)[] | no |  |  |
| `location` | [Location](/format/reference/objects/location) | no |  |  |
| `profiles` | string[] | no | format `uri` |  |
| `well_type` | string | no |  |  |
| `well_purpose` | string[] | no |  |  |
| `name` | string | no |  |  |
| `well_driller` | string | no |  |  |
| `construction_date` | string | no | pattern `^\d{4}-\d{2}-\d{2}$` |  |
| `obs` | string | no |  |  |
| `lat` | number | no |  |  |
| `lng` | number | no |  |  |
| `elevation` | number | no |  |  |
| `well_depth` | number | no |  |  |
| `bore_hole` | [BoreHole](/format/reference/objects/bore-hole)[] | yes |  |  |
| `well_case` | [WellCase](/format/reference/objects/well-case)[] | yes |  |  |
| `reduction` | [Reduction](/format/reference/objects/reduction)[] | yes |  |  |
| `well_screen` | [WellScreen](/format/reference/objects/well-screen)[] | yes |  |  |
| `surface_case` | [SurfaceCase](/format/reference/objects/surface-case)[] | yes |  |  |
| `hole_fill` | [HoleFill](/format/reference/objects/hole-fill)[] | yes |  |  |
| `centralizers` | [Centralizer](/format/reference/objects/centralizer)[] | no |  |  |
| `cement_pad` | [CementPad](/format/reference/objects/cement-pad) | no |  |  |
| `lithology` | [Lithology](/format/reference/objects/lithology)[] | yes |  |  |
| `fractures` | [Fracture](/format/reference/objects/fracture)[] | yes |  |  |
| `caves` | [Cave](/format/reference/objects/cave)[] | yes |  |  |
| `hydrodynamic_events` | [HydrodynamicEvent](/format/reference/objects/hydrodynamic-event)[] | no |  |  |
| `aquifer_analysis` | [AquiferAnalysis](/format/reference/objects/aquifer-analysis)[] | no |  |  |
| `history_logs` | [HistoryLogEntry](/format/reference/objects/history-log-entry)[] | no |  |  |
| `attachments` | [Attachment](/format/reference/objects/attachment)[] | no |  |  |
| `pump_installations` | [PumpInstallation](/format/reference/objects/pump-installation)[] | no |  |  |
| `permits` | [Permit](/format/reference/objects/permit)[] | no |  |  |
| `meters` | [Meter](/format/reference/objects/meter)[] | no |  |  |
| `production` | [Production](/format/reference/objects/production)[] | no |  |  |
| `operating_regime` | [OperatingRegime](/format/reference/objects/operating-regime)[] | no |  |  |
| `water_samples` | [WaterSample](/format/reference/objects/water-sample)[] | no |  |  |