# Object reference

> Every object of the .well format and its fields, generated from the JSON Schema.

One page per block of a .well file, generated from the [JSON Schema](https://welldot.org/schema/v2/well.schema.json). Each page lists the fields, their types and constraints, and links to the prose definition in the specification.

| Object | Property | Description |
| --- | --- | --- |
| [Well](/format/reference/objects/well) | (root) | The .well open format — a JSON standard for water well data. Depths in meters, diameters in millimeters, measured from ground level. |
| [WellId](/format/reference/objects/well-id) | `well_id` | The well_id optional block of a .well file: a list of WellId objects. |
| [Location](/format/reference/objects/location) | `location` | The location optional block of a .well file: one Location object. |
| [BoreHole](/format/reference/objects/bore-hole) | `bore_hole` | The bore_hole block of a .well file: a list of BoreHole objects. |
| [WellCase](/format/reference/objects/well-case) | `well_case` | The well_case block of a .well file: a list of WellCase objects. |
| [Reduction](/format/reference/objects/reduction) | `reduction` | The reduction block of a .well file: a list of Reduction objects. |
| [WellScreen](/format/reference/objects/well-screen) | `well_screen` | The well_screen block of a .well file: a list of WellScreen objects. |
| [SurfaceCase](/format/reference/objects/surface-case) | `surface_case` | The surface_case block of a .well file: a list of SurfaceCase objects. |
| [HoleFill](/format/reference/objects/hole-fill) | `hole_fill` | The hole_fill block of a .well file: a list of HoleFill objects. |
| [Centralizer](/format/reference/objects/centralizer) | `centralizers` | The centralizers optional block of a .well file: a list of Centralizer objects. |
| [CementPad](/format/reference/objects/cement-pad) | `cement_pad` | The cement_pad optional block of a .well file: one CementPad object. |
| [Lithology](/format/reference/objects/lithology) | `lithology` | The lithology block of a .well file: a list of Lithology objects. |
| [Fracture](/format/reference/objects/fracture) | `fractures` | The fractures block of a .well file: a list of Fracture objects. |
| [Cave](/format/reference/objects/cave) | `caves` | The caves block of a .well file: a list of Cave objects. |
| [HydrodynamicEvent](/format/reference/objects/hydrodynamic-event) | `hydrodynamic_events` | The hydrodynamic_events optional block of a .well file: a list of HydrodynamicEvent objects. |
| [AquiferAnalysis](/format/reference/objects/aquifer-analysis) | `aquifer_analysis` | The aquifer_analysis optional block of a .well file: a list of AquiferAnalysis objects. |
| [HistoryLogEntry](/format/reference/objects/history-log-entry) | `history_logs` | The history_logs optional block of a .well file: a list of HistoryLogEntry objects. |
| [Attachment](/format/reference/objects/attachment) | `attachments` | The attachments optional block of a .well file: a list of Attachment objects. |
| [PumpInstallation](/format/reference/objects/pump-installation) | `pump_installations` | The pump_installations optional block of a .well file: a list of PumpInstallation objects. |
| [Permit](/format/reference/objects/permit) | `permits` | The permits optional block of a .well file: a list of Permit objects. |
| [Meter](/format/reference/objects/meter) | `meters` | The meters optional block of a .well file: a list of Meter objects. |
| [Production](/format/reference/objects/production) | `production` | The production optional block of a .well file: a list of Production objects. |
| [OperatingRegime](/format/reference/objects/operating-regime) | `operating_regime` | The operating_regime optional block of a .well file: a list of OperatingRegime objects. |
| [WaterSample](/format/reference/objects/water-sample) | `water_samples` | The water_samples optional block of a .well file: a list of WaterSample objects. |