Evaluating Fault and Cap Rock Seals

This volume constitutes the proceedings of the AAPG Hedberg conference on seals held in Barossa Valley, South Australia, in 2002. The key driver for both the Hedberg conference and this publication was the recognition that knowledge of risk in the estimation of sealing capacity and fault-seal potential is important in making judgments at the exploration, appraisal, and development stages of the petroleum business. In addition, incorporating seal risk in the overall assessment of hydrocarbons in place can affect decisions to drill prospects and the location of appraisal and development wells, as well as reserve estimation. Improved methods to estimate seal capacity and fault integrity can lead to savings in well costs, improved recoveries through optimum placement of wells, and improved estimates of hydrocarbon in place. This volume contains 18 chapters that reflect the spectrum of presentations at the conference. The knowledge imparted by these chapters will be a window on the state of seal knowledge at this juncture of time and includes topics such as seal failure related to basin-scale processes, the role of geomechanics in seals, and the economic evaluation of prospects with a top seal risk.
Distinct-element Stress Modeling in the Penola Trough, Otway Basin, South Australia
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Published:January 01, 2005
Abstract
The Penola Trough of the Otway Basin, South Australia, is host to five economic gas fields containing an estimated 120 bcf of original gas in place in fault-related traps. However, throughout this trough, many other fault-dependent traps contain paleocolumns or partial paleocolumns. In 2001, the Balnaves 1 well discovered a semibreached structure. This structure was originally thought to be low risk because its associated fault was optimally oriented to seal with respect to the interpreted present-day maximum horizontal stress direction. On subsequent analysis of the wellbore image data, an open conductive fracture network was observed in the seal around...
- Australasia
- Australia
- Cretaceous
- discrete element analysis
- finite element analysis
- Lower Cretaceous
- Mesozoic
- natural gas
- numerical models
- Otway Basin
- petroleum
- petroleum exploration
- sealing
- sensitivity analysis
- South Australia
- structural traps
- traps
- Penola Trough
- Pretty Hill Formation
- Sawpit Sandstone