1. Lower Pennsylvanian Well Log Interpretations by Richard Andrews March 2009

2. Typical modern down-hole wireline equipment
Length in feet
Caliper
Gamma-ray
Neutron
Density
Induction (resistivity)
SP sensor
Tension

3. Siberts Well #1 Upper zone Lower zone 0 API 150 0 ohms 50
SP & GR Resistivity Conductivity
API ohms
Upper zone
See Detailed section
Lower zone
See Detailed section

4. PE; Density & Neutron Porosity K
GR & SP
2800
Resistivity
Detailed logs Siberts Well #1 – Upper zone PE
GR & CAL
2800
PE; Density & Neutron Porosity

5. Detailed logs Siberts Well #1 – Lower zone
GR, SP, & CAL Resistivity
6 Inches K

6. Detailed logs Siberts Well #1 – Lower zone
GR & Cal Density & Neutron Φ in PE
3100
3200

7. Questions for the Lower Pennsylvanian log exercise
What company drilled this well? Who owned the mineral rights?? What is the well
identification (other than its API number) and what does it mean?
2. “Joe”, a petroleum engineer from Texas designed the drilling parameters for this well. It is
being drilled in an area experiencing significant over-pressurization despite its shallow depth.
What is going to happen to “Joe’s” well if he hits pay knowing the type of mud he used?
Why wasn’t the well logged to the surface?
What is the reference datum for the well logs?
What matrix density was used to calibrate the porosity logs?
How many GR API units define the shale base-line?
7. What is the lithology throughout the upper and lower detailed sections?
Color sandstone = yellow, carbonates = blue
Identify zone(s) of mudcake buildup.
9. What is the cross-plot porosity between 3,270’-3,280’?
What is the lithology?
What is the bulk density (not porosity) and resistivity of the shale between 3,030’-3,050’
and between 3,125’-3,164’ and why the difference?
What is the cross plot porosity between 3166 – 3180? What causes the large separation
between the two log traces??
In the interval 3,160-3,210, why is the SP response greater at the base despite both
intervals having ~same cross-plot porosity? Why is the resistivity higher in the upper half?
What is the Rt at 2,788’; 3,175’; and at 3,204’?
Why isn’t there a significant SP deflection at 2,788’?
15. What is the density porosity at 3,113’? Explain.