The SPWLA Permian Basin Chapter

Technical Lunch and Learn
 
Tuesday, March 26, 2024 at 11:30 - 1:00 PM CST
Bush Convention Center
Downstairs Meeting Rooms

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“Adaptive analytical techniques and workflows for cutting samples, utilizing geochemistry, mineralogy, petrography, and water immersion porosity: an aid to petrophysical characterization & exploration in the Delaware Basin
By: Milly Wright and Michael Nieto



Abstract:
In this talk, we present, a modified workflow for the assessment of reservoir quality in cutting samples. This workflow has been specifically designed to generate reliable information from rock cuttings and focuses on the generation of data to determine mineralogy, bulk density, porosity, and digenetic history. Ultimately also increasing understanding of the depositional environment, without the detailed core analysis.
Increasingly in the Delaware basin operators are looking at secondary targets, and potentially expanding acreage in underdeveloped areas that may have been overlooked within the Basin. Often the only material available to assess these units are cutting samples, often from repositories where the volume of material available is limited. In this study we focus our dataset on Bone Springs samples, however, this workflow is easily implemented in other units.
We show that by adapting analytical techniques that are commonly implemented on core, it is possible to produce meaningful and defendable data from cuttings material. These workflows are not designed to replace core or SWC analysis, but instead provide a screening dataset that can be fed into log calibrations and petrophysical models to aid exploration studies.
Our workflow can be broken up into three different groupings of analysis:
1. XRF (X-ray fluorescence) analysis, which is used as a screening tool to determine which samples should be selected for furthermore detailed analysis. XRF analysis is useful in this case as a non-destructive process where samples can be reused for other analyses.
Once acquired XRF data are used to assess basic differences in rock composition and allow these samples to be grouped into general facies bins which can then focus additional analysis. We can also discard samples at this point that seem poor in quality and not representative of the formation.
2. Mineral and petrographic analysis. Samples are subjected to XRD (X-ray diffraction) to determine the suite of minerals present. Of specific interest is the amount of clay (and species), quartz, and dolomite/calcite. Once identified, it’s important to understand the distribution of these minerals in the rock and their transport and/or diagenetic history. For this part of the program, we use petrographic analysis.
3. Density and porosity. Finally, we want to not only understand the rock, but also the pore system. Using a combination of WIP (water immersion porosity) and XRD it’s possible to generate bulk density, matrix density & grain density measurements from cutting samples, from which porosity can be calculated.
By adopting this workflow on cutting material it is possible to produce a dataset that can readily be integrated into geological and petrophysical models as well as proving a direct tie into log data from offset wells.


Speakers Biographies:
Milly Wright is co-founder and commercial director at RohmTek in Houston TX. Milly graduated from the University of Leicester with an honors degree in geology in 2000. She then went on to complete an MS in geology at the University of Houston in 2010, with research focused on chemostratigraphic applications to mud rocks in fluvio-deltaic depositional environments in the Ferron Sandstone, Utah. Milly was a director of Chemostrat International Ltd from 2006 to 2013, stepping down from the UK-based board to concentrate on the development of Chemostrat Inc. in the Americas from 2013-2022 before co-founding RohmTek 2022. Milly has continued to publish research based on the applications of inorganic whole-rock geochemical data to geosciences and to the oil industry and regularly presents papers at local and international conferences.

Michael Nieto is the Director of Operations at Rohmtek. He held various positions with growing responsibility at Premier Oilfield Group before joining Rohmtek. He holds Bachelor's and Master's degrees in Geological Sciences from the University of Texas. His Master's Thesis title was: Chemostratigraphic and Tephrochronologic Record of Cenomanian-Turonian Eagle Ford, South Texas, USA.

 

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Permian Basin Chapter of the SPWLA


Next Meeting: 
April 23, 2024

Monthly Meetings: 4th Tuesday of Most Months


More Information:
  PermianBasin at spwla.org

President: Veronica Montoya 
Vice President of Technology: Chris Smith
Communications: Kate La Fleur
Secretary:
Jennifer Reeves
Treasurer:
Sebastian Ramiro-Ramirez