Geostatistics for Naturally Fractured Reservoirs

• Author / Creator

  Niven, Eric B

• A common problem in naturally fractured reservoirs (NFRs) is a lack of data caused by few
  wells; or at least, few wells with core or borehole images. Secondary data (such as seismic) can be used to improve predictions of fracture intensity in between the wells. Common geostatistical techniques for incorporating secondary data rely heavily on the correlation coefficient, which is influenced by outliers and whose uncertainty is usually unknown or not assessed in practice. A novel method is developed for calculating a robust correlation coefficient and propagating uncertainty in the correlation through reservoir modelling of fracture intensity. Discrete fracture networks (DFNs) are created to reproduce the models of fracture intensity.

  Current DFN modelling techniques incorporate and honour some geological information such as intensity and orientation data. However, most DFN modelling algorithms and software do not account for similarity in the orientation of nearby fractures, fracture network connectivity or fracture spacing in an explicit manner. This thesis shows that some natural fracture networks are not realistically modelled by conventional techniques. A new discrete fracture network simulation algorithm is developed, which works by simulating more fractures than are required and iterating to find a subset that best matches target spatial statistics. It is shown that the proposed simulation algorithm results in fracture networks that are more geologically realistic compared with the traditional methods. The increase in geological realism is expected to lead to better resource predictions and economic decisions for reservoir management.

• Subjects / Keywords

  • Naturally fractured reservoirs
  • Geostatistics
  • Correlations
  • Discrete fracture network

• Graduation date

  Spring 2013

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3803G

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.