THE AIM OF THIS PROJECT IS TO MAKE A SIGNIFICANT BREAKTHROUGH AS TO THE QUALITY OF THE INTERPRETATION OF 2D AND 3D SEISMIC DATA BY USING NEW INTERPRETATIVE PROCESSING AND AN EXPERT SYSTEM.
A prototype seismic interpretation monitoring and guidance system has been implemented to prove the feasibility of a knowledge based system that effectively improves the quality and efficiency of structural seismic interpretation. The system is based on a limited set of knowledge sources.
All functionality of the system is based on the formal description and explicit use of geophysical and geological knowledge. This knowledge is not always suitable for direct use by the system. Representations have been found dealing with the signal and spatial character of geophysical and geological knowledge, as well as with the discrepancy between theory and practice. Syntactic descriptions have been used to overcome some of these problems.
Each formalized piece of knowledge serves as the basis for a knowledge source (KS) in the system. Together these KSs constitute the knowledge base. Each KS is a module able to use the knowledge it is based upon in the different fashions as required by the monitoring and guidance functions of the system.
A semantic information model serves as the basis for the system's internal database which has been constructed as an object oriented deductive database. From it all information necessary to support the interpreter can be retrieved. When a piece of information is not available, the database management system will call predefined procedures to obtain it. Caching of deduced information takes place optionally.
The monitoring and guidance module is designed to be an integrated part of an interactive seismic workstation. While the workstation is being used to interpret seismic data, the monitoring and guidance module monitors the actions of the interpreter in a separate background process. The system is designed to carry the interpretation together with the user to an optimal solution. The system is able to explain its conclusions in a convenient way using natural language and graphics.
The system was developed using the logical programm ing language Prolog.
THE PRESENT GENERATION WORKSTATIONS DO IMPROVE THE EFFICIENCY OF THE INTERPRETATION OF SEISMIC DATA, ESPECIALLY AS TO 3D SURVEYS, BUT THERE IS A NEED FOR IMPROVED QUALITY IN THE INTERPRETATION PROCESSES. IT IS INTENTED TO DEVELOP AN INFORMATION SYSTEM WHICH SHOULD BE ABLE TO ACHIEVE A SIGNIFICANT BREAKTHROUGH IN THIS FIELD BY IMPLEMENTING NEW INTERPRETATIVE PROCESSING TECHNIQUES AND MAKING USE OF EXPERT SYSTEMS. THE SYSTEM WILL ALLOW THE AUTOMATION OF ROUTINE INTERPRETATIONS. TO SECURE THE IMPLEMENTATION OF THE DEVELOPED SOFTWARE SYSTEM ON FUTURE COMPUTER SYSTEMS THE FOLLOWING STANDARDS WILL BE MAINTAINED.
OPERATING SYSTEM: UNIX SY. V WITH 4.2 BSD ENHANCEMENTS; LANGUAGES: FORTRAN 77 AND C; GRAPHICS: GKS; WINDOW MANAGER: UNDER EVALUATION.
THE INTERPRETATIVE PROCESSING WILL ENABLE THE EXTRACTION OF PHYSICAL PARAMETERS FROM STACKED DATA BY APPLYING THE FOLLOWING PROCEDURE:
A) REMOVE TEMPORAL DISPERSION
B) REMOVE SPATIAL DISPERSION,
C) SELECT REGION OF INTEREST
D) APPLY ALGORITHM TO EXTRACT THE GEOLOGICAL PARAMETERS.
FAST DECONVOLUTION TECHNIQUES AND K-F/X-F MIGRATION SCHEMES NEEDED FOR POINTS A) AND B) WILL BE IMPLEMENTED FOR LOCAL OPTIMIZATION. EXISTING ALGORITHMS WILL BE USED AS WELL AS NEW ONES DEVELOPED IN COOPERATION WITH DELFT UNIVERSITY OF TECHNOLOGY.
AS TO THE EXPERT SYSTEM, A SEARCH FOR OPTIMAL CHOICES FROM DIFFERENT METHODS OF KNOWLEDGE ENGINEERING (SEMANTIC NETWORKS, PRODUCTION-RULES, FRAME AND SCRIPT, ETC.) AND FROM METHODS FOR ACCESSING THE KNOWLEDGE BASE (DEPTH FIRST SEARCH BACKWARD CHAINING, FORWARD CHAINING, HEURISTIC SEARCH METHODS, PROBLEM REDUCTION ETC.) WILL BE MADE.
SOME OF THE FEATURES OF THE EXPERT SYSTEM WILL BE:
- THE ABILITY TO START AND CONTROL EXTERNAL PROCESSING PROCEDURES (E.G. INTERPRETATIVE PROCESSING);
- THE CONNECTION TO A LARGE EXTERNAL GEOLOGICAL DATABASE,
- THE CONNECTION TO A VERY USER-FRIENDLY USER-INTERFACE, INVOLVING THE APPLICATION OF MULTIWINDOWING, POP-UP MENUS AND ICONS, GRAPHICAL INPUT AND OUTPUT.
A NEW GENERATION INTERACTIVE STAND-ALONE SEISMIC INTERPRETATION WORKSTATION (DELFT SYSTEM) IS BEING DEVELOPED IN COOPERATION WITH TNO, DELFT GEOPHYSICAL BV AND CDC BENELUX. THIS SYSTEM IS SUITABLE FOR THE INTERPRETATION OF BOTH 2D AND 3D SEISMIC DATA AND WILL BE USED AS A TOOL FOR THE PROPOSED RESEARCH WORK.