Project Info

 

Background

 

Karst-modified carbonate reservoirs account for approximately 30-50% of the hydrocarbon production in the U. S. Midcontinent. These reservoirs are often characterized by low matrix permeability, fluid control problems, and low hydrocarbon recoveries. Reservoir compartmentalization and production are commonly thought to be related to the processes of subaerial weathering, thermobaric (hydrothermal) fluids, and tectonic faulting and fracturing. Fractures can be one of the most important controls on development of permeability and hydraulic flow units in karst reservoirs.

 

Karst-modified areas may contain vast systems of caves, sinkholes, fracture-controlled solution features, vuggy porosity, and collapse breccias; however, the amount of karst overprinting can vary laterally and the role of karst in influencing reservoir character can range from extensive to insignificant. Even where karst is extensively developed, karst processes can enhance or destroy reservoir properties. Prediction of where karst is, or is not a dominant control on reservoir character can be difficult because data from reservoirs are typically either large scale (e.g., regional maps) or sparse (from sets of individual bore holes).

 

New technology is critical to the optimization of karst-modified reservoirs, and new multi-trace, geometric seismic attributes have the potential to image karst sinkholes, field-scale fracture systems, and other usually sub seismic features in relatively low-cost, conventionally acquired 3-D seismic surveys. In order to advance this imaging technology for the development and management of karst-modified reservoirs, these attributes must be calibrated at the reservoir scale. In this project, calibration will be conducted for three Midcontinent karst-modified reservoirs (in west Texas, Colorado, and Kansas) that represent a diversity of lithologies, karst processes, and porosity/permeability systems.

 

Approach

 

Conduct an integrated study of three Paleozoic karst-modified reservoirs (the Permian San Andres in west Texas, the Mississippian Spergen in Colorado, and the Ordovician Arbuckle in Kansas) that represent a diversity of lithologies, karst processes, and porosity/permeability systems.

 

Key Deliverables

  • Seismic attribute catalog of karst features
  • Integrated 3-D reservoir geomodels
  • Reservoir simulations
  • Seismic-based best-practice workflow for
    • identifying karst features and associated reservoir heterogeneity
    • predicting lithology, porosity, and permeability
    • quantifying karst-associated reservoir properties
  • Models of new well paths

 

Schedule

 

 

 


http://www.kgs.ku.edu/SEISKARST/index.html

Last Modified November 2005