This standard was prepared by the API Subcommittee on Recommended
Format for Digital Well Log Data. The content is based on a concept
and proposal originally submitted to API by Schlumberger Well Services.
This publication was under jurisdiction of the American Petroleum
Institute Production Department's Executive Committee on
Drilling and Production Practices until June 1998, when
Petrotechnical Open Software Corporation (POSC) accepted its
This publication specifies a format for digital well log data, called
here the Digital Log Interchange Standard (DLIS). This format may
be used for the recording of well log data on magnetic tape as well
as on other storage media.
Anyone may use this standard who desires to do so, subject to the
terms of the
POSC Software License Agreement.
Suggestions for revisions or additions are invited and should be
Requests for permission to reproduce any part
of the material published herein shall be addressed to
API RP66 V1 was originally published by the API in May 1991
with a clause indicating that it would not be considered
an operative API styandard
five years after its publication date, unless reaffirmed
This document, POSC RP66 V1, is considered to be applicable
indefinitely, i. e., until withdrawn or deprecated by
POSC, with no requirement for periodic reaffirmation or
Structure: How Is This Document Organized?
This document is divided into seven chapters, six appendices, and a
- Chapter 1:
- Chapter 2:
DATA ORGANIZATION, a description of the physical and logical
hierarchies, their organizations and relationships
- Chapter 3:
LOGICAL RECORD SYNTAX, a description of how logical records
- Chapter 4:
SEMANTIC TERMINOLOGY AND RULES, a summary of important concepts
and general rules for defining elements of the standard
- Chapter 5:
SEMANTICS: STATIC AND FRAME DATA, a description of Frames,
the Objects required to define them, and the Objects which establish
the parameters and environment for processing Frames
- Chapter 6:
SEMANTICS: TRANSIENT DATA, a description of the Objects
that convey messages and signify changes during acquisition and
processing of Frames
- Chapter 7:
SEMANTICS: DICTIONARIES, a description of the Objects that
specify the semantic structure of the standard and that specify
dictionary-controlled names used by the standard
- Appendix A:
LOGICAL RECORD TYPES, a list of defined Types for Public
and Private Logical Records
- Appendix B:
REPRESENTATION CODES, a list of Representation Codes
- Appendix C:
PROPERTY INDICATORS, a list of indicators used to designate
the processing or corrections performed on data
- Appendix D:
CHANGEABLE ATTRIBUTES, a list of those defined Attributes
that are permitted to be changed (i.e., updated) in a Logical File
- Appendix E:
CHECKSUM ALGORITHM, a description of the algorithm used
to compute the Checksum in the Logical Record Segment Trailer.
- Appendix F:
UNIT SYMBOLS, a list of symbols for base units and selected
Numerous cases of unusual capitalization appear in this document.
Capitalized terms have special, formal, technical connotations in a
DLIS context; these terms do not retain
their normal English connotations.
When such a special term is first introduced, it is italicized.
Acronyms are fully defined before they are used.
Many figures include comment numbers that associate a particular item
with a comment that appears below the figure. For example,
||C = 1, R = ASCII
||C = 1, R = IDENT
||R = (OBNAME, OBJREF)
||R = OBNAME
Figure 5-25. Attributes of Group Object
- 1. The OBJECT-TYPE Attribute specifies ...
- 2. The OBJECT-LIST Attribute is a List of references to ...
- 3. The GROUP-LIST Attribute is a List of references to ...
- The following is a mark of Schlumberger:
- The following is a mark of Digital Equipment Corporation:
- The following is a mark of AT&T:
- The following is a mark of IBM: