研究期間：10108~10207;We intend to study issues associated with CO2 subsurface geologic sequestration using wells drilled by Chinese Petroleum Corporation (CPC) in the Yunghoshan anticline and by Taipower Corporation in Changhua industrial area of western Coast. Two major tasks include: 1) in-situ stress change due to injection and depletion of CO2, and 2) induced earthquakes associated with fluid injection. Parameters needed to calculate in-situ include: pore (or formation) pressure, overburden stress, and the maximum and minimum horizontal stresses, and corresponding data include formation test, mud weight, loss of circulation, density logs, leak-off, gas cut and hydrofrac tests from boreholes will be collected. The maximum horizontal stress can be derived from frictional limit of critically stressed faults. Both borehole wall images (FMI and FMS) and caliper logs are used to infer azimuth of the maximum or minimum horizontal stress. Data of downhole electrical logging and mechanical data of the reservoir and caprock, as well as three-dimensional fault geometry will be composed in the geomechanical analyses. A maximal column height of injected CO2 can be evaluated without compromising the risk of induced earthquakes (or reactivation of pre-existing faults) through sensitivity and scenario analyses of Monte Carlo methods.
