Dow shale site tracer gas pressurization study

Systems, Science and Software (S3) has developed tracer gas/ pressurization techniques necessary to determine critical media properties of underground regions. Application of this technology is especially relevant to analysis of an oil shale retort volume. During the period 7 July to 14 July 1977, a series of tracer gas pressurization experiments were undertaken at the Dow shale site at Peck, Michigan. General objectives of this study were to: evaluate flow communication between boreholes open to both the Antrim and False Antrim layers of the retort volume; determine permeability and porosity distributions within the retort volume; and assess qualitatively the uniformity of the fracturing or rubblization within the retort volume. This report summarizes the results of the tracer gas pressurization study. The system cross-hole flow communication, permeability and porosity distributions, and fracturing uniformity are discussed in detail. The influence of these individual characteristics on the total system response is also presented. Conclusions and recommendations are made. A set of appendices is also included. The first presents graphical displays of all data, together with brief interpretive narratives. Experimental techniques are described in the second appendix. Descriptions of the analytical and numerical models used for data interpretation are presented in the final two appendices. Theresults given here represent our best effort to characterize the Dow shale site. Conclusions presented are based on the interpretation of the tracer gas pressurization data only. Our knowledge of the Dow shale site is therefore somewhat limited. We recognize that the tracer gas pressurization data taken in conjunction with additional data obtained using other diagnostic methods may lead to somewhat different conclusions as to the characteristics of the Dow site.