Abstract:

During the process of CO₂ geological sequestration suitability evaluation with analytic hierarchy method, problems include that weight of low level evaluation index is calculated with little consideration of the real research region and suitability evaluation result isn’t studied further. To solve the above problems, through calculating the index composition weight and suitability score, CO₂ geological sequestraion suitability evaluation in Ordos Basin was carried out combined with its geological feature. Then, the research of caprock closure, taking the Chang 4+5 layer in Xingzichuan oilfield for example was done. At the same time, CO₂ geological sequestration potential in deep saline aquifer and reservoir was calculated with corresponding methods. Calculated results show that the CO₂ geological sequestraion suitability in Triassic is the best, closely followed by Carboniferous-Permian and Ordovician. Meanwhile, sealing ability of Chang 4+5 caprock in Xingzichuan oilfield is good for CO₂ geological sequestraion. Moreover, the potential of CO₂ geological sequestration in deep saline aquifer and reservoir is 1.33×10 ¹⁰ t and 1.91×10 ⁹t, respectively. In addition, there are 56 suitable areas in Wuqi, Jingbian and Xingzichuan blocks in Yanchang Petroleum and its CO₂ geological sequestraion potential is about 1.77×10 ⁸ t.

Key words: CO₂ geological sequestration, Ordos Basin, Caprock closure, Analytic hierarchy process, Sequestraion potential