鄂尔多斯盆地CO2地质封存适宜性与潜力评价

针对目前利用层次分析法对CO₂地质封存进行适宜性评价过程中,极少结合研究区域实际计算低层次评价指标权重,对适宜性评价结果又缺少进一步的分析,结合鄂尔多斯盆地的地质特征,通过计算指标组成权重和适宜性得分对盆地开展了CO₂地质封存适宜性评价,并以适宜区杏子川油田长4+5盖层为例,开展了盖层封闭性评价实验研究。同时,采用相应的计算方法对鄂尔多斯盆地深部咸水层和油藏的CO₂地质封存潜力进行了计算。结果表明：鄂尔多斯盆地在三叠系开展CO₂地质封存的适宜性最好,石炭-二叠系和奥陶系则次之;杏子川油田三叠系延长组长4+5盖层对区域开展CO₂地质封存具备良好的封闭性;鄂尔多斯盆地深部咸水层和油藏的CO₂有效封存量分别为1.33×10 ¹⁰ t和1.91×10 ⁹ t,且在延长石油吴起、靖边及杏子川油田共有56个CO₂地质封存适宜区,其CO₂有效封存量可达1.77×10 ⁸ t。

Evaluation on geological sequestration suitability and potential of CO2 in Ordos Basin

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.