Question

Which of the following Logging tool combinations are required to estimate the Hydrocarbon Initial in Place (HCIP)?

• A. Resistivity Log, Neutron Log and Gamma Ray Log
• B. Sonic Log, Neutron Log and Gamma Ray Log
• C. Resistivity Log, Density Log and Gamma Ray Log
• D. Neutron Log, Density Log and Sonic Log

Hint:

For HCIP estimation, always ensure the logging suite includes gamma ray (lithology), porosity logs, and at least one resistivity tool for fluid saturation.

Answer 1

The Correct Option is A, C

Step 1: Understanding HCIP estimation.
Hydrocarbon Initial in Place (HCIP) is estimated using several reservoir parameters—porosity, water saturation, and net pay thickness. These parameters must be derived from appropriate logging tools that measure key formation properties.
Step 2: Evaluating logging tools.
To correctly estimate HCIP, the logs required must provide: - Lithology identification → Gamma Ray Log
- Porosity measurement → Neutron Log or Density Log
- Fluid saturation estimation → Resistivity Log

Step 3: Option analysis.
(A) Resistivity + Neutron + Gamma Ray → This combination gives lithology, porosity, and fluid saturation. Suitable for HCIP estimation. ✓
(B) Sonic + Neutron + Gamma Ray → Sonic log primarily gives acoustic velocity, not fluid saturation. Not sufficient. ✗
(C) Resistivity + Density + Gamma Ray → Density log gives porosity; resistivity gives water saturation; gamma ray gives lithology. Fully valid. ✓
(D) Neutron + Density + Sonic → No resistivity log, so water saturation cannot be estimated. Not suitable. ✗

Step 4: Conclusion.
Options (A) and (C) provide the correct combination of logs necessary for determining lithology, porosity, and fluid saturation—essential for HCIP estimation.