Rock typing - Understanding productivity in tight gas sands Academic Article uri icon


  • A workflow process was developed that provides a consistent procedure to systematically integrate both largescale geologic elements and smallscale rock petrology with the physical rock flow and storage properties in low-permeability sandstone reservoirs. This workflow process uses a corebased rock-typing approach to capture rock properties characteristics of light gas sands. Fundamental to this process are identification and comparison of three different rock types - depositional, petrographic, and hydraulic. Each rock type represents different physical and chemical processes affecting rock properties during the depositional and paragenetic cycles. Most tight gas sands were subjected to post-depositional diagenetic events, so a comparison of all thiree rock types will allow assessing the effect of diagenesis; on the rock physical properties. If the effects of diagenesis are minor, the permeability/porosity relationships derived for depositional rock types (using expected rock properties derived from geologic models of the depositional environments and processes) would be expected to be applicable to both petrographic and hydraulic rock types. However, as the effects of diagenesis increase in severity, magnitude, and occurrence, the original rock texture and composition, pore geometry, and physical properties will be modified. under conditions, one would expect little or no correlation of permeability/porosity relationships derived for each rock type. More importantly, use of the depositional environment and the associated (depositional) rock types to guide field-development activities would likely result in ineffective and inefficient exploitation.

published proceedings

  • JPT, Journal of Petroleum Technology

author list (cited authors)

  • Rushing, J. A., Newsham, K. E., & Blasingame, T. A.

complete list of authors

  • Rushing, JA||Newsham, KE||Blasingame, TA

publication date

  • December 2008