The vast extent of oil shale resources, amounting to roughly three trillion barrels, is well known. The potentially producible resource, if successfully exploited, may provide a long-term source of affordable oil.

Determination of the kerogen content is one of the primary tasks in the evaluation of oil shale deposits and the delineation of economically producible intervals. The presence of fresh water in the Green River formation complicates the determination of kerogen content from resistivity logs. An alternative method, based on the dielectric contrast between formation water and other formation constituents (minerals and kerogen), is offered by dielectric dispersion logging. Dielectric logs provide water-filled porosity and formation water salinity that, in combination with other logs, enable the evaluation of the formation kerogen content.

Shallow parts of the Green River deposits contain fresh formation water and are potentially connected to the near-surface fresh aquifers that serve as drinking water supplies. Operators will be required to protect freshwater aquifers from pollution by either produced hydrocarbons or saltier water from deeper formations. To achieve aquifer protection it is necessary to identify freshwater formations penetrated by the well and subsequently monitor the salinity and hydrocarbon content. Dielectric logging provides both these capabilities and is a fast and reliable method of environmental monitoring.

The Green River formation was logged with a new- generation dielectric dispersion logging tool that provides measurements of the formation dielectric constant and conductivity at multiple frequencies. Accurate interpretation of dielectric measurements requires the input of the rock matrix dielectric constant. In this paper we present a methodology for laboratory measurements of the dielectric constant of dry rocks and powders that was applied to a collection of samples from the Green River formation. We also obtained chemistry and mineralogy characterizations on the same set of samples and modeled nuclear logging responses. The correlations between the rock matrix dielectric constant and logging parameters are examined.

The dielectric and other logs are subsequently interpreted in terms of the formation water content, formation salinity, and kerogen content and compared with core measurements from an offset well.