【作者】 李海波；

【导师】 郭和坤；

【作者基本信息】 中国科学院研究生院（渗流流体力学研究所） ， 流体力学， 2008， 硕士

【摘要】 T₂截止值是T₂谱中最重要的参数之一,它选取的科学性与准确性直接影响到岩样核磁共振可动流体饱和度、束缚流体饱和度等参数的测量结果。离心方法是国内外普遍采用的确定T₂截止值方法,国内外多数专家学者选用100psi作为标定砂砾岩和碳酸岩岩心T₂截止值的最佳离心力。国外研究中砂岩T₂截止值大多在33ms左右而多数碳酸岩岩心集中在90～100ms之间,国内学者普遍认为国内沉积岩储层岩心的T₂截止值要小于33ms,还未见到火山岩油气藏岩心T₂截止值的相关报道。大量岩心分析实验结果表明,100psi作为标定岩心T₂截止值的离心力对低孔、低渗砂砾岩岩心以及碳酸岩、火山岩等特殊岩性岩心而言可能不适用。本文选取了一定数量有代表性的砂砾岩、碳酸岩和火山岩岩心进行了最佳离心力标定实验,对每块岩心均分别进行了六、七个不同离心力离心后的核磁共振测量。对本文实验选取的岩心而言,低孔、低渗砂砾岩岩心T₂截止值标定时适合的最佳离心力均大致可取200psi,而碳酸岩和火山岩岩心最佳离心力均大致可取400psi,对应的有效渗流喉道半径下限砂砾岩为0.1μm,碳酸岩和火山岩为0.05μm。在最佳离心力下,本文选取了大量有代表性的砂砾岩、碳酸岩和火山岩岩心进行了离心实验和核磁共振T₂测量,确定出了对应岩心T₂截止值大小,本文还选取了一定数量有代表性的新鲜含油砂岩湿样进行了T₂截止值标定,分析了岩心原始润湿性对T₂截止值的影响。在本文所测岩心中,砂砾岩岩心T₂截止值大多集中在几ms～30ms之间,碳酸岩岩心T₂截止值均在100ms左右,火山岩岩心T₂截止值随岩心岩性变化较大,大庆油田岩心中流纹岩平均值为87.91ms,凝灰岩平均值为52.02ms,火山角砾岩平均值为36.28ms。在保证T₂截止值准确的基础上,本文对实验岩心核磁共振束缚水饱和度与孔隙度、渗透率之间的相关性进行了细致分析,建立了火山岩岩心束缚水饱和度、可动流体饱和度分析方法,并对大庆油田部分火山岩岩心核磁分析结果与对应储层试气成果及岩心CT分析结果进行了比较。更多还原

【Abstract】 T₂ cutoff value is one of the most important parameter in T₂ spectrum. NMR measurement results of samples such as movable fluid saturation、irreducible water saturation will be scientific and accuracy when T₂ cutoff value select scientifically and accurately.Centrifugal method was general method used at home and abroad to calibrate T₂ cutoff value, and most experts and scholars at home and abroad selected 100 psi as best centrifugal force calibrating T₂ cutoff value glutenite and carbonatite cores. Most foreign scholars believed that T₂ cutoff value of sandstone cores was about 33 ms and domestic scholars generally believed that T₂ cutoff value of domestic sedimentary reservoirs cores was less than 33 ms. In majority study abroad most T₂ cutoff value of carbonatite cores distributed between 90 ms and 100ms, and never saw author relevant reports yet about T₂ cutoff value of vulcanite reservoir cores.Large number of core analysis results showed that 100 psi as the best centrifugal force of calibrating T₂ cutoff value might be not suitable for glutenite cores have low porosity and low permeability and special lithological cores such as carbonatite cores and vulcanite cores.This paper selected a certain number of representative cores of glutenite have low porosity and low permeability、carbonatite and vulcanite, and carried on best centrifugal force calibration experiments. each of cores were carried on NMR measurement after each of six or seven different centrifugal force, author can got that 200 psi was suitable to be best centrifugal force calibrating T₂ cutoff value for glutenite cores, and 400 psi was suitable for carbonatite and vulcanite cores in this paper, and corresponding lower limit of valid throat is 0.1μm for glutenite and 0.05μm for carbonatite and vulcanite.Under best centrifugal force, author selected a lot of representative Glutenite、carbonatite and vulcanite cores and carried on centrifugal experiments and NMR T₂ measurement, and determined T₂ cutoff value of each cores, This paper also selected a certain amount of representative fresh oil-bearing sandstone for calibrating T₂ cutoff value, and analyzed influence of T₂ cutoff value with original wettability of core. In this paper, T₂ cutoff value of glutenite cores mostly distributed between 10 and 30 ms, carbonatite cores were about 100ms. T₂ cutoff values of vulcanite cores changed great with lithology, and average T₂ cutoff value of rhyolite cores was 87.91 ms, tuff was 52.02 ms, and volcanic breccia was 36.28 ms.On the basis of ensuring T₂ cutoff value, author analyzed relationship between NMR irreducible water saturation in different cores and porosity、permeability, and established analytic method of irreducible water saturation、movable fluid saturation of vulcanite core. NMR results of some Daqing oilfield vulcanite cores and gas test results of corresponding reservoir and CT results were compared in this paper.更多还原