Cores and Samples

• MGRRE houses approximately 530,000 feet of core from nearly 1,850 wells drilled for oil, gas and mineral exploration; environmental research and geological mapping projects. Our core collection represents 62 of 68 Lower Peninsula counties and 2 of 15 Upper Peninsula counties. Core sample depths range from unconsolidated glacial material and bedrock at the surface, to Precambrian basement at more than 16,000 feet.
• MGRRE also archives drill cutting samples from more than 28,000 wells, mostly from Lower Peninsula counties. About 25,000 of those wells are from oil and gas exploration, and 3,000 are from water wells.
• At MGRRE, we also maintain a collection of surface outcrop samples from most of Michigan’s Paleozoic sedimentary rock formations. These samples are from natural outcrops and quarries in the Lower Peninsula and eastern Upper Peninsula.
• MGRRE has also archived over 2,500 thin sections from about 200 Michigan oil and gas wells.

Data Sets

Please contact the Michigan Geological Repository for Research and Education and give at least one week’s notice and we will make sure that the requested samples are available for you to examine.

Sampling Cuttings

The mounted cuttings are glued down to long strips of light-weight cardboard, so they can’t be sampled. The cuttings marked “vials” are in small glass vials and cannot be sampled because there is so little material. Even though those types of cuttings cannot be sampled, they are very easy to view (unlike the samples in paper envelopes). All cuttings in paper envelopes can be examined. If enough material is available, these cuttings can also be sampled. Please let us know which intervals you would like us to sample; we do the sampling ourselves while you are here and give you as much as we can (usually one to four grams), while keeping enough sample for future use. If you need a large number of cutting samples, we may have to mail those to you after your visit.

The footage range identified in our inventories for well cuttings shows what was written on the boxes. Because we have thousands of boxes, the contents inside the boxes are not known with certainty until we open them. Sometimes large footage intervals were not sampled at all, even though those intervals fall within the range indicated on the outside of the box. This is especially true with shales. We cannot guarantee cuttings within the entire interval shown—it’s more of a top and bottom indication. Also, we never know if the cuttings have been lagged, so the marked footages may be off from actual vertical depths by more than a few feet.

Sampling Cores

The staff at MGRRE can sample cores if we have sufficient material. We can take small (10 gram) or larger (20 gram) chips and make one inch plugs. We can do some sampling while you are here, but experience has taught us that we often end up mailing the majority of samples after your visit. Simply let us know where you would like the samples taken from and we will do our best to service your needs. Please note that core footages can be off from the log. Also, we rarely have copies of core gamma rays and we can’t do those here.

Well Records

When available, additional well records can be provided for your use while you are at MGRRE. Because it is helpful to look at the cuttings and cores alongside well records, we will lend you available copies of our well completion reports, wireline logs and mudlogs for your use while on site. There is no extra charge for these items unless you would like digital copies of them.

Additional Data

To view a list of our mudlogs and wireline logs and additional data, please refer to the section of this website dedicated to cores, samples and data.