Abstract

The multiple elements necessary for commercial unconventional oil production are discussed.

Deposition, compaction, chemical changes leading to different hydrocarbon being generated as thermal maturity increases, expulsion, migration, trapping resulting in hydrocarbon accumulation and over-pressurized reservoirs with high GOR are all interrelated and point in the same direction: a low porosity, highly compacted source rock that transformed into a seal through geologic time.

A number of laboratory experiments are presented to demonstrate that high source rock porosity and permeability are not critical (or even desirable) in unconventional oil production. Natural and cut fluorescence in the source and in the reservoir rock is exemplified for both oil and gas windows. Shale porosity and permeability experiments are presented showing the different issues. These issues are the reasons why unconventional core analysis does not have an API standard.

The issues can be addressed and avoided by performing a number of measurements that are designed to optimize hydrocarbon production: sweet zone identification, lateral placement based on hydrocarbon generation, gas reserves (as part of the reservoir material balance), extended gas composition (indicating type of hydrocarbon generation, fracturing (He), and contaminant gases), as well as Drop Shape Analysis (DSA) a fast and precise wettability measurement (now possible even at millimeter scale) used to optimize completion fluids.