Page 305 - Practical Well Planning and Drilling Manual

Section 2 revised 11/00/bc 1/17/01 12:04 PM Page 281

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2.8

Formation Evaluation

(The logging books referenced in this text are from Schlumberger, but
other companies may offer similar books)
Formation evaluation includes several different technological
approaches. These techniques are applicable at different stages of the
well. The cost of each must be considered; most are fairly expensive.
However, it is an investment that should repay more than it costs over
the life of the well in improved production and reduced future drilling
and workover costs.

2.8.1. Electric Logging and Sampling

Electric logs are specified by the exploration department to evalu-
ate the formations that have been drilled through. Drilling also can
gain a lot of useful information from logs; it seems in most operating
companies that the drillers do not have much say in the logging pro-
gram or in the interpretation work that is required.
New logging techniques are being developed all the time and of
course what follows cannot be an exhaustive list. The reader is urged
to become familiar with the logging company used, their products,
what analyses can be done, and what it costs.

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