Foreword

This specification was originally prepared by the Subcommittee on Standard Format for Digital Well data. In June 1996 it was designated a recommended practice by the American Petroleum Institute [API] Exploration & Production Department's Executive Committee on Drilling and Production Practices. In June 1998 stewardship of the document was transfered from API to Petroleum Open Standards Consortium [POSC].

Background and Purpose

A wide variety of digital data is acquired, exchanged, and stored by petroleum industry businesses using an equally wide variety of data formats. Most of these formats have been around for many years and were designed for very specific needs. As a result, they reflect the limitations of early computing hardware and are typically oriented to one type of data. Although relatively simple to implement, many formats lack the flexibility or sufficient self-descriptive features to accommodate evolving data exchange needs.

Recommended Practice 66, Version 1 [RP66V1] was introduced as an enhanced exchange format for well data. It incorporated the useful features of earlier formats and extended them by removing some of their historical limitations. The primary features of RP66 V1 were machine independence, self-description, semantic extensibility, and efficient handling of bulk data. It has been implemented and is used widely for exchange of well data.

Following the introduction of RP66 by the API, a number of efforts by other oil industry groups to develop data exchange formats began to mature and converge toward the adoption of RP66, creating a major opportunity to have just one standard exchange format for all oilfield data. However, the strong bias of RP66 toward well data was a stumbling block. In addition, introduction of new high-capacity storage devices created a need to expand the RP66 physical binding mechanism, and experience in using RP66 generated ideas for improvements. Working closely with other industry groups, the API Subcommittee on Recommended Format for Well Data developed a set of modifications to RP66, which have resulted in the current RP66, Version 2 (RP66 V2), which is described in this document.

RP66 V2 retains the essential features of RP66 V1 and is completely upward compatible. That is, any data recorded under RP66 V1 can be translated into RP66 V2 format.

The following list summarizes the differences between RP66 V1 and RP66 V2.

Organization of RP66, V2

RP66, V2 consists of Parts 1 through 9, plus Appendix A. These parts are briefly described below:

PART 1: MODEL AND METHODOLOGY.
This part describes the data model upon which the format is based and the methodology for specifying schemas - namely, object types, attributes, and the rules about them.
PART 2: LOGICAL FORMAT.
This part describes the logical organization and representation of data, including the definitions and uses of storage sets, logical files, visible records, logical records, sets, objects, attributes, and values. It also describes naming and referencing rules as well as bindings between logical records and visible records and includes specifications of all representation codes used in the format.
PART 3: PHYSICAL BINDINGS.
This part describes how storage unit labels and visible records are recorded on various common medium types, including 9-track magnetic tape and random access disk files. It also describes the use of filemarks and partitions where applicable.
PART 4: THE API-SI UNIT MODEL.
This part describes a unit model based on le Système International d'Unités (SI) from which a wide variety of units can be expressed. The unit model supports a general method for computing unit conversion coefficients for dimensionally-related units.
PART 5: API-SI UNIT SYMBOLS.
This part lists and defines the unit symbols recognized under the unit model described in Part 4.
PART 6: BASIC SCHEMA.
This part specifies the object types administered by POSC using organization code 0 (zero). This schema includes certain basic object types such as FILE-HEADER and ORIGIN, which are required by all implementations, as well as other object types such as FRAME and CHANNEL, which are standard mechanisms for describing the storage of dynamic (or bulk) data.
PART 7: BASIC SCHEMA DICTIONARY.
This part lists and describes reference values for attributes belonging to the basic schema.
PART 8: DLIS SCHEMA.
This part specifies the Digital Log Interchange Standard (DLIS) schema object types administered by POSC using organization code 66. This schema includes object types particularly oriented toward recording well log data.
PART 9: DLIS SCHEMA DICTIONARY.
This part lists and describes reference values for attributes belonging to the DLIS schema.
APPENDIX A: ORGANIZATION CODES.
This appendix lists currently-assigned organization codes.

References

This document makes reference to the following entities (documents or organizations):