Abstract: Petrophysical Characterization of Flow Properties in Shallow Crystalline Rocks and Transition Material

MATTOX, CRYSTAL A.

The purpose of this investigation is to gain a better understanding of flow characteristics in fractured materials through detailed analysis of a unique data set with continuous cores and geophysical logs from four closely spaced wells. The wells were drilled by the U.S. Geological Survey in 1996 and each penetrates to a depth of approximately 600 feet.

Microresistivity imaging logs (Formation MicroScanner) were obtained on each well. A complete logging suite, including digital sonic, array induction, gamma ray, compensated neutron, and density, was obtained from one of the wells. Specifically, fracture characteristics, petrophysical properties, and flow properties will be examined in the cores and corresponding log responses will be analyzed and fully calibrated to the core properties.

There are several original aspects of this research. Close well spacing (approximately 500 feet) facilitates the correlation of fractures between wells. Within the lower 500 feet in each well, flow is confined to the fractures in a single porosity system with the matrix being impermeable rock allowing flow to be analyzed without the complication of flow also through the matrix.

This research will allow for a more accurate prediction of fluid flow such as oil and gas migration through fractured systems and improved modeling of hydrocarbon contaminant movement from the surface into this type of ground water system.  

AAPG Search and Discovery Article #90940©1997 AAPG Foundation Grants-in-Aid