CPG Case Analysis & Practical Application 2

Question 1

A wildcat well encounters unexpected overpressure at 10,000 ft in a shale sequence. What is the most likely cause?

Accepted Answer

Hydrocarbon generation and fluid expansion in a sealed compartment

Answer

Overpressure in sealed shale sequences at depth is most commonly caused by hydrocarbon generation creating fluid expansion within a pressure compartment.

Question 2

A prospect has four-way dip closure but seismic amplitude anomalies are absent. Which interpretation is most appropriate?

Accepted Answer

The trap may contain brine or tight rock rather than commercial hydrocarbons

Answer

Absence of amplitude anomalies in a structurally closed trap suggests either water-saturated reservoir or tight rock with insufficient impedance contrast.

Question 3

During field appraisal, two wells on opposite flanks of an anticline both show oil-water contacts at different depths. What does this most likely indicate?

Accepted Answer

Multiple reservoir compartments separated by a permeability barrier or fault

Answer

Different OWC depths on opposite flanks typically indicate compartmentalization caused by faults or stratigraphic barriers separating the reservoir.

Question 4

A geologist is evaluating a turbidite channel play. The best analog to constrain net-to-gross ratio would be:

Accepted Answer

Outcrop studies of exhumed turbidite systems with similar depositional setting

Answer

Outcrop analogs from comparable turbidite systems provide the most direct constraints on architecture, net-to-gross, and connectivity.

Question 5

A production well shows rapid water breakthrough only 6 months after first oil. The most diagnostic first step is to:

Accepted Answer

Run a water tracer test or analyze water chemistry to identify the water source

Answer

Identifying whether breakthrough is from the aquifer, injector, or a behind-pipe zone requires chemical fingerprinting or tracer analysis before any remediation.

(CPG) Certified Petroleum Geologist Practice Test

(CPG) Certified Petroleum Geologist Practice Test

CPG Case Analysis & Practical Application 2