Passionate about drill cuttings

Underutilized samples can generate high quality digital datasets to assist in detailed understanding of sub-surface plays in Alaska

Petroleum News

Drill cuttings are an invaluable source of quality organic and inorganic geological data and yet are often underutilized. Hundreds of thousands of cuttings are stored in warehouses and repositories across the length and breadth of the country, spanning decades of drilling activity.

Alaska’s largest and most comprehensive archive of geologic samples - the Geologic Materials Center, or GMC - in Anchorage, stores approximately 500,000 cuttings from offshore and onshore wells on federal, state and private land across the state, covering decades of exploration and development. In addition, large oil and gas companies store additional proprietary cuttings samples.

The GMC is dedicated to helping geoscientists and the public understand Alaska geology through the acquisition and preservation of physical and digital collections.

“With the onset of new analytical technologies and AI driven software applications, all these samples could generate high quality digital datasets that will assist in detailed understanding of sub-surface plays at a fraction of the cost of drilling a new exploration well,” Dr. Guy Oliver, a 25 year-plus veteran in the upstream oil and gas sector and a fan of the GMC, told Petroleum News.

Standard techniques are now available to correctly and accurately depth-match fresh and historic samples to wireline log suites.

Preparation key

“Consistent sample preparation is key when trying to interpret and correlate data from samples acquired by different vendors/operators.”

Understanding “base mineralogy, potential organic richness and mud type are some of the important factors to consider when making sure a sample is properly prepared. Correct washing and drying procedures are fundamental for preserving mineral species and evidence of hydrocarbons,” Oliver said.

Once correctly washed and dried, “a base analytical workflow should be undertaken to ensure that every sample is consistently measured, thus allowing for confident correlations sample to sample, well to well, and both vertically and laterally across the basin/play/asset,” he said, noting that typically, this base workflow could consist of digital photography, grainsize and shape determination, digital color images (both white light and UV light) color averaging and elemental data.

Beyond this base workflow, on a case-by-case basis, “additional valuable data can be obtained, such as biostratigraphy, mineralogical data, and organic richness and maturity,” Oliver said.

All these collected digital data can be used to help “constrain rock physics models or as input to regional or field subsurface models. Reliable, accurate and consistent data is the key to unlocking or confirming regional and field specific reservoir/seal trends,” he said.

And with Big Data and AI technologies now readily available to all, Oliver said having access to these vast “integration ready” datasets will revolutionize the way we explore for, or appraise, our energy assets.

Cuttings can be a “relatively inexpensive but incredibly valuable dataset” that could help to unlock the future potential of our energy plays for years to come, he said.

“As an industry, we need to make the most of these datasets, by digitally unlocking their data potential and having the confidence to use these data in our subsurface evaluations,” Oliver said.

GMC’s mission

On its website the GMC lists the following statistics:

* 3,096 Alaska energy wells

* 26,500,000 feet of energy strata drilled

* 16,700,000 representative feet of energy core and cuttings

* 76,000 linear feet of energy core

* 22,000 Alaska minerals boreholes

* 766,000 feet of mineral rock drilled

* 617,000 representative feet of mineral core and cuttings

* 354,000 linear feet of mineral core

* 250,000 processed slides and thin sections

* 507,000 surface samples