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为评价阿布扎比海上油田的水驱动态,对碳酸盐岩水平岩样进行了特殊岩心分析,分析是在新鲜和老化两种状态下通过在X射线CT扫描仪下进行观测实现的。表面直观观测和X射线CT扫描识别明显显示,岩心是非均质的,局部含有一些形成孔洞型孔隙空间的藻类碎屑和一些能形成低孔隙区域的矿物。本研究的主要目的是评价岩心的非均质性对水驱动态和后续采收率的影响。Amott和USBM试验结果表明了新鲜岩心从中间润湿到水湿的性质,这与预计的结果相矛盾。这意味着,钻井液污染可能改变了原始润湿条件。在这种条件下进行的水驱试验获得了相当高的采收率。X射线CT扫描通过识别到的均匀的水前缘推进和高波及效率证实了这一结果。在Amott和USBM试验中得到的结果表明老化岩心为油湿性质,采收率稍微低于新鲜岩心,但是仍然令人满意。X射线CT扫描还证明流动是均匀的。由此可见,尽管局部出现了非均质性,但是老化岩心试验还是获得了高采收率。用JBN方法推导的新鲜和老化岩心的Kr曲线稍有不同。
In order to evaluate the waterflooding behavior of the offshore oilfields in Abu Dhabi, special core analyzes of carbonate rock samples were conducted and analyzed under both fresh and aged conditions by observation under an X-ray CT scanner. Visual observation of the surface and identification by X-ray CT scan clearly show that the core is heterogeneous and locally contains some algal debris that forms a pore-type pore space and some minerals that can form a low-porosity region. The main purpose of this study is to evaluate the effect of core heterogeneity on waterflooding and subsequent recovery. The Amott and USBM test results show the nature of fresh core wetting from the middle to the wet, which contradicts the expected results. This means that drilling fluid contamination may change the original wetting conditions. Waterflood tests conducted under these conditions yielded quite high recovery. X-ray CT scanning confirmed this result with the identified uniform waterfront propulsion and high sweep efficiency. The results obtained in the Amott and USBM tests show that the aged core is oil-wet with a slightly lower recovery rate than fresh cores, but is still satisfactory. X-ray CT scans also show that the flow is uniform. From this, it can be seen that despite the local heterogeneity, the aged core test still achieves high oil recovery. Kr curves of fresh and aged cores derived using the JBN method are slightly different.