All the data acquired during a seismic survey is meaningless if unprocessed. To make it usable, data processing must be conducted. Computer based processes include - filtering, stacking, migration and other analysis. A very large computing power, geophysical processes and highly specialized software are required in order to process the data. Data processing is costly and time-consuming exercise and can take up to one year or more to process, depending on the size of the data. More advanced process, such as Prestack Depth Migration (PSDM) are more complex and take even more time.
Modern days, seismic vessels are equipped with preliminary processing capabilities, which result in better data obtained and ability to adjust seismic data acquisition programme, as data becomes available. Reprocessing old 3D data is an opportunity to find more hydrocarbons, as processing technologies and techniques evolve over time and provide better output. Data process industry is very manpower intensive. Although there are number of companies who provide data processing services, the industry is known to be with huge backlogs. Hence, as much as 1 year could be required in order to book a slot to process sesmic data.
Data interpretation is a process of interpreting processed data by geophysicists and geologists, together with other geo-scientific data available, if any. This integrated interpretation provides a detailed understanding of the geology and the likelihood of finding hydrocarbons. Collaborative and team effort is required to interpret the data, as geology is a very subjective science.
There are number of methods used, such as PSDM, attribute analysis, amplitude variation with offset (AVO) analysis, reservoir characterization and many more. Based on the various interpretation methods, structural geological maps are produced that map out the reservoir quality and the distribution of oil and gas.
In both data processing and interpretation, experience of people and knowledge of the particular area is the key.