Interactive Graphics and Data Storage in Large Scale Log Analysis
Authors: Browne E.J.P. 
Published: December 2007

This paper was prepared for the 48th Annual Fall Meeting of the Society of Petroleum Engineers of AIME, to be held in Las Vegas., Nev., Sept. 30-Oct. 3, 1973. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon requested to the Editor of the appropriate journal, provided agreement to give proper credit is made.

Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussions may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

This paper describes and illustrates the use and formulation of a Data Storage and Interactive Graphics Computer System. This is used to store and depth correlate voluminous quantities of log, core and other reservoir data. All recording and processing is done by computer with minimal human intervention, which results in increased accuracy and efficiency.

Introduction

One of the problems of log data evaluation is preparing the data so that it is in a form which lends itself to computer analysis. With some exceptions, the data gathering problem has been solved, and many advances have been made to make analytical interpretation by computer of such data more physically meaningful.

Fortunately, the calculations which arise in log analysis, even at their most complex, are fairly simple, and although each calculation is usually short, it is invariably conducted on quantities of data so large that more time and effort are spent in preparing and conditioning the data than in the analysis itself. Today, except for certain measurements, mostly made in the laboratory, data is directly collected in digital form, and even analog recordings are now converted to digital form for computer evaluation.

One problem which is universal in log data analysis is the depth correlation of data taken from different logging devices. These logging devices accumulate data on different runs into a borehole, with the result that the depth dependent data is not, at first, depth correlated.

This data must be correlated to bring it back to a defined reference depth and, except for the introduction of incremental plotters to display digital data, there has been little success in automating this depth correlation procedure. Attempts have been made to design procedure. Attempts have been made to design mathematical algorithms for depth correlation, but these have, to date, not proved entirely suitable. The handling and depth correlating of log data is a routine and frequently occurring problem to which no acceptable solution is readily available. Anyone who has ever tried to do depth correction by the conventional manual operation would welcome the relief from the repetitive transfer of data from digital form to analog plots with the intervening hand shifting and recording.