The use of drill cuttings in reservoir characterization is becoming increasingly significant to understanding reservoir properties.
This is especially heightened in today’s world where conventional coring is not always an option. Nuclear Magnetic Resonance (NMR) has proven to be an invaluable tool in the analysis of unconventionals. We are now adding to its value by presenting a new NMR cuttings measurement to determine porosity that could be used in the lab as a cost-effective core analysis technique. This idea has been around for some time but has had limited success…until now.
Where other methods have used cut-offs to account for the overestimation in porosity due to water on the surface of the cuttings, our method takes physical measures to remove the surface water and then measure the porosity directly. An added benefit of removing the surface water allows us to perform these measurements on cuttings of a much smaller size, down to 1/70th of an inch. This is important for cuttings derived using modern drill bits such as Polycrystalline Diamond Compact (PDC). This measurement can be performed on fresh cuttings straight from the wellsite or on historical samples from a cuttings database. We have extensive experience working with samples from various shale plays around the globe.
Below is a table showing the accuracy of our measurement comparing porosity of core plugs to cuttings from the same respective depth. These specific samples are from the Utica Shale play.
| Core Sample | Sample Depth (ft) | Porosity | Cuttings Sample | Sample Depth (ft) | Porosity |
|---|---|---|---|---|---|
| 1 | 12139.9 | 4.1 p.u. | 1a | 12130-121400 | 3.9 p.u. |
| 2 | 12187.4 | 5.1 p.u. | 2a | 12190-12200 | 5.1 p.u. |
| 3 | 12239.9 | 6.8 p.u. | 3a | 12230-12260 | 7.2 p.u., 6.6 p.u. |
| 4 | 12275.5 | 8.1 p.u. | 4a + 5a | 12260-12290 | 8.2 p.u., 7.8 p.u. |
| 5 | 12287.0 | 7.5 p.u. | 4a + 5a | 12260-12290 | 8.2 p.u., 7.8 p.u. |
To obtain more information on our NMR cuttings measurement watch our webinar!