Planning for Drilling and Installation of Boreholes for Cross Hole Hydrologic Tests in Overpressured Accretionary Complexes

University Of California-Santa Cruz, Santa Cruz CA

Investigators

Abstract

Modeling studies will be performed to plan new drilling for the next generation of cross-hole and single well in situ hydrologic tests in overpressured accretionary complexes. Planning for future drilling and hydrologic tests must address two concerns. The first concern is that formation conditions during previous tests were clearly disturbed but the extent of disturbance and implications for the test results are poorly understood. The second concern is the possibility that future tests may interfere with long-term monitoring efforts by perturbing the in situ conditions. Two types of models will be used to address the important questions. Using consolidation models, changes in physical properties around boreholes when the formation is open to hydrostatic conditions during extended periods will be examined. Using pore pressure and solute transport models, different single and two well test scenarios will be used to design optimal tests and assess their effect on long-term monitoring.