Introduction

Volume Data Store (VDS) is a storage format for fast random access to multi-dimensional (up to 6D) volumetric data. The VDS format has been developed by Bluware Inc. and has seen extensive industrial deployments over the last two decades. The format is contributed by Bluware Inc. to the Open Group Open Subsurface Data Universe Forum (OSDU) (The Open Group, u.d.).

An open-source reference software implementation which can read and write VDS has been contributed by Bluware Inc. to the OSDU. This implementation is named OpenVDS and supports several programming languages. It can be included in software products with no encumberments towards Bluware Inc.

VDS has been designed to handle extremely large volumes, up to petabytes in size, with variable sized compressed bricks. The VDS format is very flexible and can store any kind data representable as arrays with key/value-pair metadata. In particular, data commonly used in seismic processing can be stored along with all necessary metadata. This makes it possible to go from legacy formats to VDS and back, while retaining all metadata.

VDS files may be used to represent E&P data types such as regularized single-Z horizons/height-maps (2D), seismic lines (2D), pre-stack volumes (3D-5D), post-stack volumes (3D), geobody volumes (3D-5D), and attributes volumes of any dimensionality up to 6D.

The format has been designed primarily to support random access and on-demand fetching of data, this enables applications that are responsive and interactive as well as efficient I/O for high-performance computing or machine learning workloads.

Note

While the VDS specification supports user-defined named metadata, the Metadata chapter describes the set of predefined required and optional metadata, as defined and managed by the OSDU Data Definitions subcommittee, for VDS data to be used in seismic applications. Additional named metadata types should be brought up with the OSDU Data Definitions subcommittee for inclusion in the predefined list.

There are two different storage backends for VDSs:

  1. Single-file Container

    The single-file version of VDS contains all data (main data, auxiliary channels, metadata, indexes) in a single-file and is suitable for storing and retrieval on a filesystem.

  2. Cloud Object Store

    The object store version is an adaptation of the single-file container for storage and retrieval on cloud-based object stores. Utilizing a similar structure in the object store version allows applications a trivial transition from local legacy type access to cloud-based object store access.

For the remainder of this document, a VDS dataset will refer to a single dataset organized as described by this specification. The actual realization of the dataset will not be a single object when the data is organized in a cloud-based object store.

Terminology

  • Metadata

    The term metadata used in this document refers to what is commonly called header data` or name-value pair data embedded within the OpenVDS format or any legacy format, e.g. nDI vt, SEG-Y etc. This is distinct and separate from the Open Subsurface Data Universe (OSDU) work product, work product component and file metadata. Clearly, specific, individual OSDU metadata values may be obtained from corresponding OpenVDS metadata values.