Recent Developments in Geophysics: ABSTRACT

Abstract

The search for oil is based on the correlation process. One core is compared with another; one well log is matched against another; a seismic trace is correlated with the adjacent traces; and a seismic record is correlated with the adjacent records. The correlation process should be examined more closely. In the last few years. the process of correlating a well log with a seismic reflection record has been greatly improved. The improvement has been accomplished by changing the presentation of the well log so that, in its new form, the well log data are more comparable with the data on the seismic record. In other words, the well log curve has been filtered and redrawn to the seismic time scale. This process of filtering and changing the scale can be used in correlating on well log with another. In the process of correlation, the manner of presenting the data is most important. Because of recent improvements in seismic instruments, it is now much easier to make seismic record sections. A record section presents many data on a single sheet of paper; no data are omitted; and the data can be presented in various ways. This flexibility in the process of storing and reproducing data greatly facilitates the correlation process. Faults, uncomformities, steep dips, and unusual interference phenomena can be seen on a record section when they might not be seen in a study of separate seismic records. Much of the present correlation process is subjective. The correlator merely decides that one wiggle looks like another wiggle. The process is not quantitative. It is possible to make a mathematical correlation between two curves. Because the use of magnetic tape is so well developed, it is now easy to build a computor to perform this mathematical correlation. The correlation of exploration data by means of a computer is new. At this time, the possibilities can not be evaluated. End_of_Article - Last_Page 1773------------