Short-term and long-term behaviour of clay shale as caprock for in situ thermal (heavy oil) recovery processes

点击翻译按钮获取中文摘要

Steam stimulation is one of the viable in situ methods to recover heavy oil from deep oil sand reservoirs in Alberta. For sustainable development, a competent caprock must exist above the oil sand reservoir to prevent any upward hydraulic and thermal migration into the overburden. The hydraulic and structural integrity of the caprock must be maintained as these in situ thermal recovery processes induce significant short-term and long-term deformation in the caprock. The main objectives of the proposal research are to develop quantitative methodologies in assessing natural geological formations such as shale and mudstone as caprock for in situ thermal steam-stimulated processes. Natural caprock cores will be tested in laboratory under the short-term and long-term environmental changes encountered in the field. The short-term environmental changes include shearing deformation, high temperature heating, and pore pressure elevation. The short-term structural and hydraulic behaviour of the caprock subjected to these severe environmental conditions will be studied using a new high temperature and pressure testing facility. The long-term behaviour such as swelling under pore fluid chemistry alteration and creep under sustained shearing and heating will be also investigated. Long-term degradation in caprock structural-hydraulic integrity is the key research subject. New innovative accelerated testing methods will be developed to shorten the test duration. New criteria on structural and hydraulic integrity will be developed from this research investigation for performance evaluation of shale and mudstone as caprock for thermal recovery processes. The findings from this research investigation can be transferred to other research activities such as carbon storage and waste water disposal.