Nautral Fractures and Mechanical Stratigraphy in the Permian Basin (El Paso, TX to Carlsbad, NM)

INSTRUCTOR: John C. Lorenz, PhD and Scott P. Cooper MS
DISCIPLINE: Field Courses
CEUS: 3.2


WHO SHOULD ATTENDGeologists who need to characterize and understand fracture systems and their effects on reservoir permeability from core and outcrops, who need to be able to differentiate between natural and induced fractures in cores, and who would like to be able to predict the effects of lithology on fracturing.

Engineers who want to understand fracture permeability in relationship to the in situ stress system, the interaction of natural fractures with hydraulic stimulation fractures, and the important differences between extension and shear fractures in controlling individual fracture permeability and fracture network interconnectedness.

Petrophysicists who want an understanding of the significance of different fracture characteristics on image logs and the reliability of image logs in capturing the characteristics of fractures.
Seismologists who want a better understanding of subsurface fracture systems and their potential effects on seismic signals.

Managers who want an understanding of the technologies and methodologies required to adequately characterize a fractured reservoir.

COURSE DESCRIPTIONOutcrops in south-eastern New Mexico offer excellent examples of natural fractures in different lithologies. This serves as the background for discussions on mechanical stratigraphic controls of fracturing and production in conventional and unconventional reservoirs. Included in the associated lectures is a 65-piece teaching collection of natural and induced fractures in core that students will work with during class exercises.

Except for a few minor examples, the Paleozoic unconventional shales of most interest in the Permian Basin do not crop out. However, excellent fractured outcrops of associated strata illustrate fracturing in the Delaware part of the Permian basin in the Carlsbad, NM area. These include exposures of the back-reef Queen Sandstone, the deep-marine Brushy and Cherry Canyon sandstones, and several limestones in front of the Capitan Reef. An outcrop of the Bone Spring shale will be examined south of El Capitan, and significant fracturing in the reef limestones themselves is exposed in the numerous canyons that cut through the reef. A trip through Carlsbad Caverns to view the cave as well as dissolution along fracture trends in limestones is included.


  • This is a hands-on field trip and classroom experience.
  • The student will obtain insights into fracture mechanics and the origins of fractures, and uses those concepts in an applied sense to instill an understanding of natural fractures and their potential effects on reservoirs.
  • Through discussion on the outcrop the attendees will learn to differentiate fractures by type and the effects of these fracture types on reservoir permeability, and what fracture types to expect in different structural domains and reservoirs.
  • Attendees will obtain an understanding of the interactions between natural fractures, in situ stresses, and stimulation fractures.
  • Students will come away from the course with an appreciation of the wide range of structures that fall under the basket term “fracture”, and an understanding that different fracture types do not all have the same effect on hydrocarbon reservoirs.



Day 0

  • Arrive in El Paso, TX
  • Classroom: Start lectures with dinner at 6 pm, Topics include: Safety, Natural Fractures, and overviews of the Stratigraphy and Field trip
  • Overnight: El Paso, TX


Day 1

  • Field: Brushy Basin Formation (sandstone), Bone Spring Formation (shale), Carbonates in the Guadalupe Mountains National Park
  • Overnight: Carlsbad, NM


Day 2

  • Field: Interbedded Queen sandstones and dolomites, and Cherry Canyon sandstones
  • Overnight: Carlsbad, NM


Day 3

  • Field: Capitan reef outcrops in Carlsbad Caverns National Park, Exploration and tour of Carlsbad Caverns
  • Overnight: El Paso, TX


Day 4

  • Classroom: Topics, Fractures in limestone vs sandstone vs shale, Natural and induced fractures in the subsurface, Effects of natural fractures on reservoir production, Interaction between natural fractures and hydraulic stimulation fractures, Core viewing and instruction includes our 65-piece teaching collection of natural and induced fractures in core
  • Overnight: El Paso, TX


Day 5

  • Depart from El Paso, TX