Multiple data set integration for structural and stratigraphic analysis of Oil and Gas Bearing formation using GIS
 K M Mohamed Elias Cauvery Basin, Tamilnadu, India E-mail: kmelias@lycos.com
Introduction:
Exploration for oil and gas has always depended on surface maps of rock types and structures that point directly to, or at least hint at, subsurface conditions favorable for generation and accumulation of oil and gas. Mapping begins with reconnaissance, and if that indicates favorable condition for generation of hydrocarbons, then detailed mapping begins. Originally, both of these give 3-D constructions of subsurface structural and stratigraphic traps for the hydrocarbons. Then, they are sampled by drilling and their properties measured. IRS, Land sat, Spot and other space imaging systems, serve as mega-photos that depict large areas, within which clues to subsurface conditions may be evident. The advent of higher-resolution space imagery proved a boon to energy sector seeking new sources of fossil fuels. Sometimes the imagery proved especially sensitive to subtle indications of interior structures. For instance, fractures around structures in known oil/gas fields may extend further, as seen in the coherent space images, than suspected from groundwork. Also, drainage patterns at broader scales may reflect control by underlying rocks involved in suitable traps. And even vegetation distribution may disclose signs of structure. These and other indicators discernible in space imagery appealed to exploration geologists as another means to survey large areas Lineament Analysis in Geology: Lineament investigations for geological structural analysis have oftentimes been viewed as untrustworthy. This view perhaps may be caused by the subjectivity of the lineament identification process. Geologists conducting lineament analysis have generally considered all lineaments as equal regardless of their appearances in the data set(s) being used, or else used subjective processes in an attempt to identify major trends. Also, the utilization of multiple data sets in the identification and analysis of lineaments has rarely been employed. This is rather unfortunate, as it appears that surficial data sets, such as satellite imagery, aerial photo, digital elevation models (DEMs), and geological maps integrated with subsurface information such as seismic reflection geophysics and formation structure maps, provide very powerful capabilities in lineament analysis. One of the major capabilities in lineament identification made possible using data set integration is the ability to identify lineaments based on their characteristics. This is an important issue as combining data may help lend credibility to certain types of lineaments. Geographic Information Systems (GIS) functionality, such as vector and raster spatial analysis and overlay, can be employed for structural analysis and evaluation of significance, using powerful software programs such as Arc View, Arc/Info, Erdas Imagine, and Ilwis Lineaments on Remote Sensing Imagery: All the lineaments observed and identified on remote-sensing data of various types and scales and on topographic maps, constitute a definite expression of the structure of the earths in the form of linearly organized elements of the landscape.
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