Structural geology and geomechanics

Evert Uitentuis 
Dick Nieuwland 
5 days

Business context

Structural analysis is a key part of risk assessment in subsurface evaluations. This course is intended to provide participants with the skills to optimize both exploration lead evaluation and reservoir development with respect to structural complexities in hydrocarbon reservoirs such as structural geometries, conduits and seals.

The participants will be introduced to the main elements of geo-mechanics, which then serve as a basis to understand structural geometries and kinematics. Examples can never provide the complete picture, whereas a generic geo-mechanical approach is universally applicable. Case histories still provide good illustration materials as it helps understanding mechanics and tectonics.

Participants are encouraged to bring actual cases of their current work to the workshop for general discussion and integrated 'hands-on' problem solving during the workshop. Basic interpretation elements will be discussed  for each tectonic regime.

Who should attend

Exploration and Development Geologists, Geophysicists and Petroleum Engineers  working on the development of hydrocarbons in areas with (complex) tectonic regimes.

Course content

The course program is centred around structural geometries and geo-mechanical principles behind the development of structural features such as folds, faults and fractures.

  • The roles of structural geology in E&P.
  • Basic geo-mechanics theory, Mohr circle analysis.
  • Analogue Modelling of Structural Processes
  • Overview Tectonic regimes (e.g. Extensional, Compressional, Strike-Slip)
  • Fault generation, reactivation, sealing and analysis
  • Salt tectonics and diapirism, inversion
  • Subsurface Pressures
  • Impact of rock deformation on Hydrocarbon Generation and Development

Learning, methods and tools

Exercises and case histories presented throughout the week  provide a strong link between theory and application.

Relevant examples presented by participants can be treated as part of the course if presented in advance, including some example material.

Day by day programme

Day 1: Introduction to Structural Geology and Geo-mechanics

  • Course Introduction and Overview
  • To create a 'common ground', the first day will include general aspects of the application of structural geology and geo-mechanics in the E&P business.
  • Introduction to stress and strain, rock mechanics and the application of this subject to geological phenomena as encountered in the oil and gas business.
  • The concept (and limitations) of analogue modelling will be discussed.

  Day 2: Origin of Structural Deformation; Folding, Tectonic Regimes

  • Folding: Slow deformation may lead to folding. Types, nomenclature and the relationship with hydrocarbon occurrences.
  • Tectonic Regimes
  • The various regimes will be discussed according to classification by Anderson

- Extensional tectonics

- Hydrocarbon Occurrence in Extensional Basins (with Case Histories Structural)

- Geometries and fault properties characteristic for extensional tectonic regimes such as rifts, deltas.

Day 3: Tectonic Regimes

  • Anderson classification (continued)

- Strike-slip tectonics: Structural geometries and fault properties that are characteristic for strike-slip tectonic regimes will be treated whereby the 3D nature of this tectonic setting including pitfalls and traps in structural interpretation will receive special attention.

- Compressional tectonics: fold-and-thrust belts;

- Structural geometries and fault properties that are characteristic for compressional tectonic regimes.

  • Salt-tectonics (halokinesis), occurrence, process, drilling issues.
  • The mechanics of fault reactivation - multi-phase tectonics. (inversion tectonics).

Day 4: Conduits and seals: Faults and Fractures

  • The morning session will be used to discuss fracture mechanics, fracture types, natural fracture systems and their impact on reservoir characteristics and production strategies, hydrocarbon entrapment and fluid flow.
  • Fracture systems: fracture mechanics, reservoir examples and outcrop examples.
  • Analysis of fault and fracture systems, including Integrating Faults on a map, fractal properties of fault and fractures and prediction of sub-seismic faults.
  • Subsurface pressures. The origin and effects of normal and abnormal subsurface pressure will be discussed.
  • Borehole-stability: Understanding the effect of subsurface pressures on the drilling process is essential for a safe and efficient Field Development.

Day 5: Fault sealing (cont'd);

  • Fault sealing mechanisms and approaches to evaluate seal integrity in exploration and in production scenarios will be dealt with. Case examples and exercises will be used.
  • Course Round Up and Close Out