Welcome to our fracture studies website. This site details our decades of work with natural fractures and their implications to production. Enjoy and please contact us for additional information.




The Atlas is available through Wiley Blackwell and AAPG.

The Atlas contains over 550 color photographs and figures, with complete detailed descriptions that illustrate the multitude of natural and induced fractures in core. The atlas is divided into three main sections: 1) Natural Fractures, 2) Induced Fractures, and 3) Artifacts. The natural fractures section highlights extension and shear fractures and various other natural fracture types plus the mineralization (real and false) or dissolution that may alter the permeability of these fractures. The induced fractures section details the wide-variety of fractures that can be formed during the drilling and handling processes. This section includes the all-important discussion on how to differentiate natural from induced fractures in core and what induced fractures can be useful for like determining the orientation of the in situ principal stresses. The last section describes the fascinating artifacts you may come across during a lifetime of logging core.

The online review by The Geological Society (of London) states "this is a high quality publication that should be an essential text in any and all core facilities and essential reading for anyone who spends time looking at core." The full review can be found here.

Also - Check out Susan Nash's AAPG Learn!Blog webpage for a great interview titled "All About Fractures: Interview with John Lorenz and Scott Cooper" concerning the Atlas and fractures both natural and induced.



We are developing a series of short natural-fracture articles for LinkedIn and similiar venues. When completed, these papers will be available here for downloading and reference.

1) Dynamically Compatible Fractures in Sandstone Outcrops (Spring 2018), download.

This paper describes an outcrop of the Chinle Formation in north-central New Mexico that exposes two lithologically dissimilar sandstones. These sandstones are cut by significantly different but dynamically-compatible fracture types. This article describes dynamically compatible fractures and their implications to reservoir permeability systems.

2) An Outcrop Example of Variable Fracture Mode in a Sandstone (Summer 2018), download.

The fracture-failure mode of a given lithology is not a constant. This is illustrated by fractures in outcrops of coarse Permian arkoses in central New Mexico where a set of older, dip-slip conjugate shear fractures strikes 70 to an unrelated set of younger vertical extension fractures. The significant change in fracture mode was controlled by either changes in the external stress environment or by modifications of the mechanical properties of the rock during cementation and diagenesis. Predictions of subsurface fractures must consider the potential for varying mechanical properties in the rock.



Publically offered courses are listed below. In-house courses focusing on your company's specific needs and proprietary data are available upon request.

Fractured and Shale Reservoirs: From Geologic Concepts to Reservoir Models
Organization: Canadian Society of Exploration Geophysicists, Doodle Train Continuing Education Week
Date: November 5-6, 2018
Location: Calgary, Alberta, Canada
Instructor: Ahmed Ouenes, FracGeo, www.fracgeo.com, and Scott Cooper, FractureStudies LLC
Registration: CSEG Doodletrain, www.cseg.ca/education/doodletrain/register, or phone 1-403-262-0015



In January 2018 we produced a webinar with Subsurface Consultants & Associates (SCA): a recording of the presentation is publically available at scacompanies.com/webinars-on-demand/ .

The webinar explores the importance of differentiating between extension and shear fractures due to the significantly different effects of the two fracture types on reservoir permeability and productivity. The two types create dissimilar drainage anisotropies and fracture-interconnectivity systems. Fractures of the two systems also have distinctly different orientations relative to the in situ stress axes, governing the potential for reservoir stimulation. Finally, fracture type governs the degree of stress sensitivity of fracture apertures to reservoir pressure drawdown during production.

Extension and shear fracture systems therefore require different stimulation and production philosophies. In order to recognize shear vs. extension fracture systems it is necessary to understand, fully characterize, and not just count fractures in core. Characterizing fractures is not wasteful "science", it is the work required to understand a reservoir and to efficiently produce the hydrocarbons it contains and to optimize recovery and profitability.

In 2017, FractureStudies LLC also presented a webinar for Explorock SAC of Lima, Peru. The webinar is publicly available, click here.


FractureStudies LLC provides insight and solutions for:

  • Fracture-controlled reservoir flow dynamics
  • Fracture-controlled production behavior
  • Better well placement
  • Better completion techniques
  • EOR activities
  • Directional drilling
  • Structural interpretations and tectonic histories
  • Increased ultimate recovery



1. The advantages and importance of knowledgeable fracture analysis:
Fractures are easy to count and to measure for dip and strike, but that does not make them simple, easy to understand, or interpret. Unless the fracture types are understood, statistical analyses of fractures are meaningless. There are many types of fractures, and each has different effects on reservoirs. Fractures vary by lithology and by stress regime, and can either enhance or degrade reservoir permeability. Many types of fracture permeability can change during production.

2. Why this fracture-analysis team is unique:
Fracture analysis requires insight into fracture type and origin in order to make valid three-dimensional assessments of fracture-related reservoir plumbing, and to reconstruct structural/tectonic histories. We offer more than the measurement and counting of cracks. Our long history of helping to develop the science of natural and induced fracture interpretation and analysis (see publications list), and our experience in a diverse array of fractured reservoir plays and formations, allow us unique insights into fractured-reservoir characterizations and problems.

3. Multidisciplinary interactions:
We have a proven record of providing useful, applied geological data and concepts to multidisciplinary teams--please note the themes of our published papers and the different expertise of the various co-authors. We have interacted successfully and productively with engineers, geophysicists, petrophysicists, rock mechanicists, and other experts.



  1. Fracture signatures on image logs must be calibrated with core.  Image logs commonly image less than half of the fractures in a formation.  They do not capture bed-parallel and low-angle fractures or short fractures, and they do not accurately represent fracture apertures.
  2. Image logs commonly misinterpret vertical natural fractures as induced fractures, and may capture only the set of fractures that strikes parallel to maximum horizontal stress.
  3. Once an image log is calibrated across the cored interval, the rest of the image log as well as image logs in adjacent wells become significantly more valuable.
  4. Cores allow direct measurement of reservoir matrix permeabilities.  Cannot distinguish KV from KH from Kh in logs.
  5. Cores allow direct measurement of geomechanical rock properties.
  6. Characterizations of the interactions between natural fractures and induced centerline fractures in cores provide direct evidence for the interaction of natural fractures with hydraulic stimulation fractures.
  7. Coring-induced petal and centerline fractures provide information on the in situ stress orientations.
  8. Cores show the distribution of natural fractures relative to lithology.
  9. All fractures are not equal; cores show the range of fracture sizes and types, allowing a determination of which fracture population controls reservoir permeability.
  10. Fracture faces cannot be seen in image logs, yet these surfaces that distinctions to be made between shear fractures, which form intersecting permeability networks and provide good drainage, and extension fractures, which form as parallel sets and create highly anisotropic drainage.
  11. Measured matrix permeability can be compared to reservoir system permeability calculated from well tests to indicate the contribution of fractures to reservoir permeability system.



A partial list of our publications is attached here as a PDF.

Two papers published in the American Association of Petroleum Geologists Bulletin (one on fractures within the Spraberry Formation the second on a fracture model based on Teapot Dome) are provided here with permission from AAPG as locked PDFs. Additional publications are available through the AAPG at www.aapg.org.

We provide several of our public-domain reports including nine Multiwell Experiment Project Reports as PDFs in our Fracture Studies/Clients page. We can provide additional articles, papers and reports on request.

Free public access to our Department of Energy reports through: Information Bridge, Department of Energy Scientific and Technical Information www.osti.gov/bridge/



Public and Private Investor Reports - previously published public papers/reports provided through links on the Case Studies/clients webpage. Private reports are available as appropriate through direct contact.

Kurdistan, Iraq – An AAPG presentation on "Fractured Reservoirs of the Shaikan Anticline, Northern Iraq" is a summary of field and core work and is available as a pdf within our FractureStudies database Shaikan Anticline. This is a singular example of some of our work done over multiple years in the Kurdistan region. Additional descriptions and photographs can be found on our FutureStudies/Contact page.

Niobrara Formation: Fracture Types and Distributions – A private-investor report in the development phase – interested and current research participants please coordinate with Dr. Lorenz on project specifics (photos).

Tensleep Formation Fracture Study Compendium – A summary of three and a half years (2007-2010) of field, outcrop and core studies on the Tensleep Formation for the Enhanced Oil Recovery Institute at the University of Wyoming.  The report is available by request at: eoriwyoming.org or as a pdf within our FractureStudies database Tensleep Formation Fracture Study Compendium.

Aerial photography: geology of production and analog areas –
John Lorenz, as a licensed pilot and flight instructor, can provide aerial images from overflights of your producing areas or analog site, field scale and aerial scale geologic assessments, or teach you how to fly. Contact John for further information.



Dr. Ahmed Ouenes/FracGeo LLC
FractureStudies for several years has co-taught classes on fractured-reservoirs and worked jointly on projects with Dr. Ahmed Ouenes of FracGeo LLC (fracgeo.com). Dr. Ouenes and FracGeo have unique fractured-reservoir modeling capabilities and are breaking new ground in the understanding of the interactions between natural fractures and hydraulic stimulation fractures.

Enhanced Oil Recovery Institute, University of Wyoming
FractureStudies has collaborated with the EORI on and off since 2001, on field trips, short courses and consultation services within Wyoming (eoriwyoming.org).

RPS/Nautilus World
FractureStudies has provided field trips and short courses and continues to offer field trips for industry through Nautilus World (nautilusworld.com).

Subsurface Consultants & Associates
FractureStudies offers short courses, field trips and consultation services for industry through SCA (scacompanies.com).


Additional Associations

Petroleum Professional Development Center of Midland College

SCAL, Inc., Midland, TX


Professional affiliations

American Association of Petroleum Geologists (AAPG)

Society of Petroleum Engineers (SPE)

Rocky Mountain Association of Geologists (RMAG)

Wyoming Geological Association (WGA)


Scott P. Cooper

Mailing Address:
99 Rainbow Road Suite 4-5 Edgewood, NM 87015-2348

John C. Lorenz

Mailing Address:
99 Rainbow Road Suite 4-5 Edgewood, NM 87015-2348

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Atlas of Natural and Induced Fractures in Core (Lorenz and Cooper, 2018).

Dueling photographers: John C. Lorenz along the Hogback monocline, northwestern San Juan basin (Lorenz and Cooper).

Creating extension fractures: Scott P. Cooper, Fort Hayes Limestone Member of the Niobrara Formation, Raton basin, Colorado (Sandia National Laboratories Technical Report, Lorenz and Cooper, 2004).

The difference between looking at slabbed core (left) and whole core (right) for fracture studies

Natural fractures account for the difference between actual well productive capacities and matrix deliverability in low-permeability sandstones of the Mesaverde Formation in the Piceance basin of Colorado (from Warpinski and Lorenz, 2007).

phto Let us provide you the courses, field trips, (all guaranteed to include lunch stops at fall aspen groves) data and/or interpretations to help analyze and produce your teams’ reservoir.