Print this pageSalvaging Dipmeters Using an Oil Field "Dinosaur"
BREIMAYER, ANITA R. P. and LAURA BIGLEY PUZIO
Accurate, directly measured dip data is critical in today's high-tech exploration environment. Dipmeters provide direct dip measurements at the wellbore. They are integral to resolving velocities in 3-D surveys, essential in evaluating thin-bedded lithologies, and useful in defining bed dips in sub-salt or structurally complex plays.
Too often, an explorationist views the tadpole plot itself as measured data. This is an error. The tadpole plot is simply one INTERPRETATION of the original dipmeter resistivity data. The optimal display of this data is the 60" = 100' scale playback. This display was the only record of the raw data before digital tapes and computer correlation were developed. Technology has rendered this "oil field dinosaur" nearly extinct. However, far from extraneous, 60" playback is the key to dipmeter quality control. The correct correlation among the different resistivity curves is the heart of the dipmeter computation.
We will offer a multi-step quality control procedure for maximizing dipmeter quality through the logging and computing process. Examples of 60" data illustrating several raw data problems that can result in confusing or unreliable tadpole plots will be presented. This information will help the explorationist assess the reliability of a tadpole plot, so that the dipmeter data can be used, or even discarded, in an appropriate, informed manner.