POSC Specifications Version 2.2

December 1997

The documentation and sample implementations in this Version 2.2 release of the POSC Specifications will be supplemented in the next few weeks with the additional materials described below. As these items become available, you will be able to download them from the following address at the POSC web site: http://www.posc.org/Epicentre.2_2/supplement.

Documentation Aids

• Additional examples of usage and guides for populating data
  
  Several EXPRESS-I examples of usage showing how data is populated in Epicentre are included with the present release. A number of additional EXPRESS-I examples will be added in the near future.
  
  Usage guides are being delivered in this release for seismic and for coordinate systems. The next usage guide to be delivered as a supplement to Version 2.2 will be for business associate. It will demonstrate how Epicentre can be used to store, not only the names of employees and business contacts, but many other useful pieces of information about them as well.

• An updated Epicentre implementation guide
  
  There is a beginning document under the Implementation section called Getting Started. This document gives information on setting up the POSC environment, building databases and loading databases. Some areas of this document are incomplete and will be supplemented in the near future.

• A Reader's Guide to POSC documentation
  
  The Reader's Guide will provide a personal perspective on effective ways of utilizing the POSC documenation. Based upon the viewpoints of selected readers, it provides a context to guide further exploration. The readers perspectives to be represented here are not only broad, but also quite experienced. This document can be used as a tool to either introduce yourself to the POSC documentation, or to expand your understanding by looking through someone else's eyes.

• ER diagrams in PostScript^® format
  
  Use these files to create a printed version of the entity relationship (ER) diagrams. This allows reference to the diagrams while reading related material online.

Implementation Tools

• Epicentre Well Log Data Loader
  
  The Epicentre Well Log Data Loader is a component of the EzTools Log Data Conversion Suite from Oilware, Inc. The Epicentre Well Log Data Loader will load heading information and curve data from LIS, DLIS, Western Atlas BIT, and a variety of ASCII log data formats including LAS Versions 1.2 and 2.0. The loader will support automatic detection of the Epicentre Version (2.0,2.1, or 2.2), and Datastore type (PDS or SDS), so that the proper information may be mapped and loaded.
  
  The EzTools Suite is a component based application which contains a Motif based User Interface, and a set of data scanning and conversion modules. The modules contained in the Epicentre Data Loading Package are as follows:
  
  
  • EzTools User Interface
  • LIS Scanning Module
  • BIT Scanning Module
  • ASCII Scanning Module
  • DLIS ScaningModule
  • Epicentre Loading Module
  • Utility Programs
  
  The free version available on the POSC web site will not be the complete application and is intended to provide basic functionality and an example of how to load Digital Well Log Data from several industry standard formats into Epicentre. The source code for much of the Epicentre Loading Module will be included. The application can not be rebuilt however without licenses for several of the Oilware libraries. The free version will have several other restrictions as noted below:
  
  
  • DLIS will not be included
  • Heading data loaded will be a subset
  • LIS loading will include fast channel curves, but not array curves
  • ASCII loading will be restricted to LAS only
  • Support for POSC datastore (PDS) only
  • Support for Epicentre Version 2.2 only
  
  See EzTools Screen Shots for a preview of the software modules that will be made available.

• Version migration tool set
  
  POSC has arranged for the development of a set of tools to support the migration of data existing in POSC data stores to Epicentre Version 2.2. This includes the following tools to be run on site against data stores to be migrated:
  
  
  • Survey tool - determines the populated footprint of a data store (from Oilfield Systems)
  • Data migration executable¹ - translates data to Version 2.2 of Epicentre (from Prism Technology)
  • Comparator - verifies that the populated footprint before and after migration are consistent (from Oilfield Systems)
  • Meta data tool - enables data stores containing data defined by Epicentre Version 2.0 to be accessed by either compatibility implementations complying with DAE Version 2.0 or with the current version² (from Prism Technology).
  
  These tools, which are run on site by a data administrator against POSC data stores, provide the basic functionality to migrate a properly configured and populated data store³ to Epicentre Version 2.2. The tools are delivered as logical (DAE) applications, linked with a compatibility implementation of the DAE.
  
  

¹In addition to the on-site tools, POSC has arranged for the development or enhancement of the following tools which are used to create the migration executable:



• Mapping tool - accepts input from the data modeler and generates a mapping definition in the syntax of the mapping compiler (enhancements to QMapper from Quinary, run by POSC data modelers)
• Mapping compiler - generates the data migration executable (developed and run by Prism Technology).

²In the POSC SIP Version 2.0, many aspects of the projection process and meta model were specific to Epicentre Version 2.0. With SIP Version 2.1, a new projection tool was specified and implemented, which required a new meta model. The result is a more general, flexible and robust approach to projection.

³The following assumptions are made about the data store prior to migration:



• The data store to be migrated is the master copy of the data it contains.
  
  To the extent that data are considered to be refreshable from an external master copy (e.g., operational databases or loader files), the migration of the data store will be ineffective unless loader files are migrated and transfers from operational databases are remapped. For data stores which solely or predominantly contain copies of data held externally, the decision to migrate data in place should be evaluated.
  
  
• The logical model conforms exactly to the published Epicentre model and the relational schema conforms exactly to the published Relational Projection of Epicentre.
  
  Extensions and variations are not supported, although the existence and population of extended entities and attributes defined according to subsetting rules defined by POSC should not prevent the migration of data conforming to Epicentre.
  
  
• The underlying relational schema is populated with data of good quality.
  
  The relational population should be a valid projection of a logical population which conforms to the structure and complies with the constraints of the logical model.
  
  Data loaded by direct SQL data loaders and applications should comprise a valid projection of a logical population which conforms to the structure and complies with the constraints of the logical model.
  
  
• The logical schema is populated with data of good quality.
  
  The logical population should be consistent with definitions, mappings, recommendations, and EXPRESS-I examples as published by POSC.