Page 39 - Well Logging and Formation Evaluation

CHAPTER 2

QUICKLOOK LOG

INTERPRETATION

Once the section TD (total depth) of the hole has been reached, the petro-
physicist will be expected to make an interpretation of the openhole logs
that have been acquired. Before starting the log interpretation, the petro-
physicist should have:

1. All the relevant daily drilling reports, including the latest deviation
data from the well, last casing depth, and mud data
2. All the latest mud-log information, including cuttings description,
shows, gas reading, and ROP (rate of penetration)
3. Logs and interpretations on hand from nearby wells and regional wells
penetrating the same formations, in particular where regional or field-
wide values of m, n, R w, rho g and fluid contacts are available
4. A copy of the contractor’s chart book

2.1 BASIC QUALITY CONTROL

Once the log arrives, the petrophysicist needs to ensure the quality of
the log data and should perform the following regimen:

1. Check that the logger’s TD and last casing shoe depths roughly match
those from the last daily drilling report.
2. Check that the derrick floor elevation and ground level (or seabed)
positions are correct.
3. Check that the log curves are on depth with each other. The tension
curve can be used to identify possible zones where the toolstring has
become temporarily stuck, which will put the curves off depth and
result in “flatlining.”

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