Abstract

There are several reasons in both conventional and unconventional settings that wells may be considered failures. The well could be a dry hole, the target formation/landing zone could be resource poor/unproductive, or a lateral could drastically underperform. Analysis of the volatiles contained in legacy geological materials (drilling cuttings, sidewall core, and/or core) associated with such wells can be used not only to carry out a post-mortem of the well, but provide important insights and opportunities going forwards. Analysis of the volatiles present in materials from dry holes can yield important information in terms of neighboring prospects, the petroleum system, and may allow for the identification of low visibility bypassed pay. In the case of under performing laterals insights that enable new completion strategies going forward may be possible.

Volatiles are extracted from legacy geological materials by crushing the material to expose new surfaces and “tight” pore spaces and then decreasing the ambient pressure to where the compounds of interest enter the gas phase at room temperature. The volatiles are then collected on a liquid nitrogen cold trap; subsequent separation, identification, and quantification is accomplished by warming the cold trap and submitting its contents to a mass spectrometer as a function of temperature. Samples older than 60+ years have been successfully assessed. A more through description of the workflow can be found in Smith and Smith (2020).

We present the analysis of volatile fluids and gases from legacy geological materials (drilling cuttings) and demonstrate the value that the analysis of these materials from dry holes or underperforming wells can provide. Both conventional and unconventional examples are presented including work done in the Gulf Coast (TX), the North Slope (AK), and the SCOOP (OK).

The predominance of legacy geological materials in in state, federal, and private repositories from dry holes or underperforming wells offers a unique opportunity learn from these failures and enable subsequent success.