World-class training for the modern energy industry

Applied Concepts of Natural Fractures: Mechanics and Characteristics in Outcrop and Core, New Mexico (G049)

Tutor(s)

John Lorenz: Co-founder and Partner, FractureStudies LLC.

Scott Cooper: Co-founder and Partner, FractureStudies LLC.

Overview

Outcrops in central New Mexico offer excellent examples of natural fractures in a variety of structural settings and lithologies. They illustrate the mechanical and stratigraphic controls on the fracture systems that in turn control permeability in most conventional and unconventional reservoirs. A world-class example of permeability-reducing shear fractures (“deformation bands”) will be visited, occurring in fluvial sandstones of the Morrison Formation. The outcrops to be visited also show fractures associated with faulting, as well as the complications associated with reactivation of extension fractures in shear. An exposition of the authors’ 65-piece teaching collection of natural and induced fractures in core is part of the course, providing the chance to compare one-dimensional core fracture data with the three-dimensional data provided by outcrops.

Duration and Logistics

5 days; a mix of classroom lectures (15%), field time (75%) and core/hand sample workshop (10%).  The course begins and ends in Albuquerque, New Mexico.

Level and Audience

Advanced. This course is intended for geoscientists, reservoir and production engineers, and petrophysicists 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. It is also for those 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.

Exertion Level

This class requires a MODERATE exertion level. The fieldwork will involve walking up and down slopes over rough ground. There will be walks of up to 1.6km (1 mile) on most days, the most strenuous being an ascent (and descent) of 60m (200 ft) over rocky ground as part of a walk of 3km (2 miles). The elevation range is 1600-2200m (5300-7200 ft), which may lead to unexpected shortness of breath for some. The central New Mexico weather in the fall is cool-warm and dry, and often windy. Transport is by SUVs. Most driving is on black-top roads, but some areas are reached by gravel or dirt roads.

Objectives

In this hands-on, application-based field trip you will learn to:

  1. Assess the origins of fractures.
  2. Understand characteristics and distributions of different types of natural fractures and their potential effects on reservoir permeability.
  3. Differentiate fractures by type, as well as predict what fracture types to expect in different structural domains and reservoirs, through discussion on the outcrop.
  4. Assess the interactions between natural fractures, in situ stresses and stimulation fractures.
  5. Appreciate the wide range of structures that fall under the basket term “fracture”, and recognize that different fracture types do not have the same effect on hydrocarbon reservoirs.
 

Sequence Stratigraphy of the Permian Basin, Texas and New Mexico (G002)

Tutor(s)

Rene Jonk: Director, ACT-Geo Consulting and Training; Honorary Professor, University of Aberdeen.

Overview

This field course is designed for geoscientists and engineers exploring and developing plays in mixed carbonate-siliciclastic systems; it is relevant to those working in the Permian Basin. The course will enhance each participant’s ability to distinguish depositional facies and play elements, based on seismic features, stratal geometries, sequence stratigraphy, diagenetic changes impacting reservoir quality and depositional models. Subsurface data from the Permian Basin, including seismic, well logs and cores, will be used to establish a sequence stratigraphic framework for the basin, with emphasis on the prediction of play element presence and quality, both for conventional and unconventional resources, including discussions on production behavior and strategies.

Duration and Logistics

A 5-day field course; a mix of field activities (60%) and classroom lectures and exercises (40%), with long days (typically 10 hours). The course begins and ends in El Paso, Texas. The first night is spent in El Paso; subsequent nights are spent in Carlsbad, New Mexico.

Level and Audience

Advanced. This course is intended for geoscientists, petrophysicists, engineers and managers who are seeking a comprehensive examination into the seismic stratigraphy of the Permian Basin.

Exertion Level

This class requires a MODERATE exertion level. Fieldwork is in west Texas and southeast New Mexico, where the weather is arid and usually hot, although cold and wet weather is possible in the spring and fall when daily temperatures range from 5–25°C (40–80°F). The course includes walks of a moderate length (up to 3.2km/2 miles) with an ascent of 305m (1000 ft), frequently over very steep and uneven ground. Transport on the course will be by mini-van. Most of the driving is on black-top roads, with some driving on graded dirt roads.

Objectives

You will learn to:

  1. Analyze exposures of carbonate shelf and ramp to siliciclastic basinal systems, in order to relate depositional facies to seismic scale geometries and sequence stratigraphy.
  2. Examine seismic scale outcrop geometries, document outcrop facies and demonstrate similarities to productive intervals in the Permian Basin.
  3. Understand how subaerial exposure, marine diagenesis and early near-surface dolomitization can affect ultimate reservoir porosity and permeability and overall reservoir geometry in subsurface.
  4. Assess changes in carbonate facies and relate these changes to depositional environments.
  5. Apply Walter’s Law and chronostratigraphic principles in core, well log and seismic interpretation, and relate to prediction of play elements and best productive intervals for unconventional resources.
  6. Analyze sequence stratigraphy for carbonates and mixed carbonate-clastic depositional systems.
  7. Interpret carbonate sequence stratigraphic patterns from outcrop, well log and seismic data.