APPLICATIONS OF CARTOGRAPHIC METHODS AND SATELLITE

Transcription

1 APPLICATIONS OF CARTOGRAPHIC METHODS AND SATELLITE IMAGES IN PRESENTATIONS OF SEISMIC DATA (GIS IN PRACTICE) Vesna Špiljak, Gordana Rafael-Gujić Exploration Department,INA-Naftaplin Šubićeva 29, Zagreb, Croatia Abstract With this work we want to present the use of databases and application in the cartographic software- CPS-3 and satellite photographs processed by means of ERDAS-IMAGINE software in order to get different illustrations of the ground base. On such bases in the coordinate system we introduce data from the base of alignments of seismic profile and other topographic marks, for the purpose of presentation of particular project in the oil and gas research. 1.Introduction CPS-3 is a computer mapping system designed to model 3-D data for geological, environmental, and GIS applications. The software features gridding and contouring options, as well as 2-D and 3-D graphic displays. Used world-wide in earth science applications, CPS-3 is a collection of software applications that enables you to model, visualize and analyze X, Y, Z data in oil and gas exploration and production. CPS-3 can model geologic structures, and with petrophysical parameters, estimate oil-in-place volume. CPS-3 reads data, creates a model from the data, and produces maps and reports from the model. Base map provides a geographic reference for the data of primary interest. A base map usually comprises cultural and political boundaries, legends, and title boxes. From we use Cartographic software CPS-3 (Schlumberger Company) in Ina-Naftaplin. This program is well known, as one of the best programs of that kind, for producing maps. During a long time working on different projects, it has shown its precision, mathematically exactness and beauty in making maps. Software is used in exploration for displaying base-maps, for interpretation seismic profiles and determines well locations. 2. Work method When we decide to begin exploration of oil and gas deposits in some area it means geophysical and geological works. After we mark shot pointing for seismic profile, from the field records in handwriting or digital form, we draw nets of profile by CPS-3 software on the base determined by the coordinates of area. If earlier boreholes exist on that area of exploration we also use their data records from the borehole base and put them on the map. That represents foundation of the base-map. According to the user s wishes, we put on the map different topographic elements: cities and villages, roads, rivers, lakes, lines and various political boundaries. After finishing and saving that map, we copy digital records in.dxf format in the ACad graphic software and paste them on the topographic base. 154

2 Figure 1. This map represents the area of Dalmacija - Ravni Kotari, the part of the Adriatic coast and Kornati islands. It is topographic map with seismic profiles, rivers, cities and boreholes. The map is creating in scale 1: Application of satellite photographs in GIS and Geology Satellites from high altitudes take photographs of the large territory of the Earth s surface. As a result of this we can observe and research the Earth as a unique unit composed of lands, seas and the atmosphere. Rapid development in technology (new satellites and sensors for shootings and measurements) and teaching methods (GIS systems, procedures of interpretations and computer data processing), is narrowly connected with the latest achievements in the area of satellite shooting and measurements. Thanks to global covering with satellite photographs, it is possible to rapidly and correctly gather information about the Earth cover, and in the three-dimensional shape generate regular and current appearance of relief of single objects and structures on the photograph. Although the remote research includes various techniques of data collecting, we have used data obtained through satellite. In the making of digital model of field we have used SPOT snapshots, and for the purpose of interpretations LANDSAT photographs. Processing of photographs is made by the computer, and we use ERDAS IMAGINE programs for the interpretation and analysis of photographs. The simplest processing of photographs is the combination of three different spectral canals. Every spectral canal is presented in different color, what enables better differentiation of field cover. 155

3 Figures 2 and 3 Part of mosaic LANDSAT satellite photograph and equal part of joined georeferenced maps scale 1: areas which includes Obrovac, Knin, Zadar and Šibenik, and the part of Kornati islands, we export 156

4 in AutoCAD program (important for making 2D drawing). Also we inserted data of seismic profile, borehole, road, line, place and towns in dxf format. On the final picture we marked the area coordinates with data necessary for easier orientation, interpretation and analysis of the ground in the determined area. Figure 4 SPOT photographs of the same area were used as bases (DEM-the digital model of field because of the three-dimensional display), and a LANDSAT photograph is joined to illustrate present status on the field. On photographs we can notice all changes on the field (water level of rivers, change of vegetation and expansion of settlements, new roads etc) We have used LANDSAT photographs because of their sizes. Scene is 183x172 km (whole shoot), and the size of pixel is 34x34 meters. We georeferenced Satellite photographs (by reason of the accuracy we usual use topographic maps 1:25000) and made their mosaic. Using prepared photograph we cut up the part of photograph which is necessary, and we add names of places for easier orientation. For geologic interpretation it is very important to know the season in which the photographs are taken, as well as the covering of the specified field. So far we have used satellite photographs in determining the most favorable topographic locations of bore-holes. 157

5 4. Conclusion Špiljak V., Rafael-Gujić G. (2004). Geologists amongst first have started to use satellite photographs in their exploration. The remote research in discovering of hydrocarbons has been already used for a long time. The main task of geologic remote research is to recognize different geologic data on images, where some classic methods of investigating can notice them with difficulty or it isn't possible to record because of, for example, compact vegetations above the geologic structure. The target is to identify potential oil structures promising for further research. With the aid of GIS technologies the database access is made easy. Spacious data in the shape of photographs or the maps can contain different geologic data. The satellite photograph can also help us as the base for planning the net of seismic surveying. The existing net displayed on the satellite photograph, for the purpose of presentation of the single project, is good and picturesque illustration of the field. 158