Page 22 - Well Logging and Formation Evaluation

12 Well Logging and Formation Evaluation

ously important that discussion take place between the petrophysicist and
the geologist about the need for coring and the various analyses that will
be performed once the core is recovered.
For a particular well, the detailed logging requirements will first be
specified within the well proposal, which will be agreed upon with other
partners and any government supervisory bodies. The proposal will typi-
cally not specify the exact models of tool to be run but will cover the
general types for the individual hole sections. Typically there will be many
items that are conditional on hydrocarbons being encountered, based on
shows encountered while drilling. For a well proposal, a typical program
might look something like this:

Exploration Well
1
17 / 2 ≤ hole section:
GR/resistivity/sonic (GR to surface)
If shows encountered include GR/density/neutron and optional pressure/
fluid sampling

1
12 / 4 ≤ hole section:
LWD GR/resistivity
Wireline GR/resistivity/density/neutron
Optional pressure/fluid sampling if hydrocarbons encountered
1
8 / 2 ≤ hole section:
LWD GR/resistivity
GR/resistivity/density/neutron
GR/dipole sonic/formation imager
Pressure/fluid sampling (sampling dependent on oil being encountered)
VSP
Sidewall samples

Development Well
1
17 / 2 ≤ hole section:
No logs required
1
12 / 4 ≤ hole section:
MWD [measurement while drilling]/GR
GR/resistivity/sonic (GR to surface)
If shows encountered include GR/density/neutron and optional pressure/
fluid sampling