Minnelusa Project: A Capstone Exercise for Junior-Level Sedimentary Rocks and Processes Lab

Dennis Kerr
,
The University of Tulsa Department of Geosciences
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Summary

The Minnelusa Project integrates core description and interpretation, lithologic unit identification from well log response, subsurface well log correlation, and subsurface mapping. The final goal is to propose and defend a drilling prospect based on a given play concept.

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Context

Audience

Sedimentary Rocks and Processes (SRP) Lab is a separate 1-credit course with a co-requisite of enrollment in 3-credit SRP Lecture. This lab is a junior-level course required for all BS degree Geosciences majors, and elective for BA degree Geosciences majors. Other students who enroll as an elective include Petroleum Engineering and Anthropology majors.

Skills and concepts that students must have mastered

  • Ability to describe and classify sedimentary rock types.
  • Recognition and description of sedimentary structures.
  • Ability to interpret sedimentary processes/environments.
  • Some experience with contouring data fields.

How the activity is situated in the course

The Project culminates approximately 11 weeks of experience, which includes 3 field exercises, in describing and interpreting sedimentary rocks.

Goals

Content/concepts goals for this activity

The Project builds in three major steps, each of which are introduced sequentially and take about a week to complete.

Part A involves the description and interpretation of a core from a single well. This task is aided by the use of a core description form. Goals include:
  1. delimiting lithologic units useful for interpretation;
  2. recognition of an unconformity; and
  3. appreciating resolution limits of core data.

Part B involves relating the core of Part A to the well log from the same well; recognition of 6 general lithologies based on well log response; and correlation lithologic units and unconformity surface across well log cross sections. Goals include:
  1. appreciation for well log response to sedimentary rocks;
  2. resolution limits of well log data (reflection back to Part A); and
  3. how iteration of work and integration of information can assist in recognition of unconformity surface (reflection back to Part A).

Part C involves construction of specific subsurface maps leading to the identification and defense of a well drilling prospect based on a play concept. directs students to produce subsurface maps that aid in generating a drilling prospect based on a play concept. Goals include:
  1. developing contouring skills;
  2. integrating perspective from Part B in to map constructions;
  3. graphic representation of 3D relationships; and
  4. written and oral presentation of data and findings.

Higher order thinking skills goals for this activity

  • Visualizing and representing 3D relationships based on information from discrete point locations.
  • Integration of data of varying types (i.e. actual rock and well log response).
  • Formulation and defense of a drilling prospect based on a given prospect model.

Other skills goals for this activity

  • Develop geologically realistic contour and paleogeologic maps.
  • Presentation of data and findings in written and oral form.

Description of the activity/assignment

The Project builds in three major steps, each of which are introduced sequentially and take about a week to complete.

Part A involves the description and interpretation of a 57-foot core from a single well. The core is a sample of the lower Goose Egg Formation and upper Minnelusa Formation. Goals include: 1) delimiting lithologic units useful for interpretation; 2) recognition of an unconformity; and 3) appreciating resolution limits of core data.

Part B tasks the students to relate the core description of Part A to the well log (GR and sonic) from the same well; depth adjustment for relating the two data types is necessary. Based on Part A and additional information provided, the well log is to be interpreted in terms of 6 lithologies. Using well log cross sections, intersecting at the cored well, the students correlate and trace the subdivisions of the upper Minnelusa, unconformity surface, and subdivisions of the lower Goose Egg. Goals include: 1) appreciation for well log response to sedimentary rocks; 2) resolution limits of well log data (reflection back to Part A); and 3) how iteration of work and integration of information can assist in recognition of unconformity surface (reflection back to Part A).

Part C directs students to produce subsurface maps that aid in generating a drilling prospect based on a play concept. The play concept is the location of a structurally tilted paleo-ridge below the sub-Goose Egg unconformity. Given a table of depth information (KB, unit tops and TD), the students construct the following maps: structure map; gross interval isopach map from a marker to base Goose Egg as a surrogate for paleotopography; paleogeologic map along the sub-Goose Egg unconformity; and a map integrating the information from the other maps to support a prospective drilling location. Finally, each student writes a defense for their prospect and participates as a team member in the oral presentation of their results. Goals include: 1) developing contouring skills; 2) integrating perspective from Part B in to map constructions; 3) graphic representation of 3D relationships; and 4) written and oral presentation of data and findings.

Determining whether students have met the goals

Results are compared to a key made by the instructor. The key is not considered "the answer" but rather "an answer". Evaluation of a student's results is based on the completeness of the assigned tasks, the geologic reasonableness of the effort, and the presentation quality of the work.

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Supporting references/URLs

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