【作者】 杨平；

【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， 2011， 硕士

【摘要】 本文利用恒速压汞技术、核磁共振技术、离心实验技术和微量驱替实验技术,对来自长庆油田的超低渗砂岩储层岩样进行研究,并将其实验结果与长庆的特低渗储层岩样和致密储层岩样的实验结果进行对比,研究了超低渗储层特征及渗流规律,得到以下结论：1.通过对储层微观孔隙结构的研究可知,长庆超低渗储层孔隙和喉道发育比特低渗储层要差,比致密储层要好。相对于特低渗储层来说,超低渗储层孔喉比较大且分布范围较宽,大喉道及大喉道所控制的孔隙体积明显较少。2.通过对储层可动流体的研究可知,长庆超低渗砂岩储层与特低渗砂岩储层可动流体饱和度都超过了40%。即使是可动流体饱和度相近的超低渗(K>0.3×10-3μm2)岩样与特低渗岩样,超低渗岩样大喉道控制的可动流体也明显少于特低渗岩样大喉道控制的可动流体；致密储层的可动流体饱和度小于特低渗和超低渗储层的可动流体饱和度,可动流体几乎全为半径小于0.2μm的小喉道所控制。长庆超低渗储层T2截止值平均值为15.22ms。3.通过对储层单相流体渗流规律的研究可知,相对于长庆特低渗储层来说,超低渗储层和致密储层注水将更加艰难。长庆渗透率小于0.3×10-3μm2的超低渗储层启动压力梯度要远高于特低渗储层,而低于致密储层；渗透率、有效喉道半径以及可动流体饱和度均对启动压力梯度有一定的影响。更多还原

【Abstract】 By using rate-controlled mercury penetration technology, NMR technology, centrifuged laboratory experiment and micro displacement experiment, this paper studied the rock samples from ultra-low permeability sandstone reservoirs in Changqing oil field. Then, the experiment results of these samples are compared with that of extra-low permeability ones and tight ones also coming from Changqing so that the reservoir characteristics and seepage law of ultra-low permeability reservoirs can be discussed. The studies provide the following results:1. From the study of reservoir microcosmic pore structure, it can be known that the pore and throat development of ultra-low permeability reservoirs in Changqing is worse than that of extra-low permeability reservoirs in Changqing and better than that of tight reservoirs in Changqing. Compared with extra-low permeability reservoirs, the pore throat ration of ultra-low permeability reservoirs is bigger and its distribution range is broader; meanwhile, the large throats and the pore volume controlled by large throats in ultra-low permeability reservoirs are far less.2. From the study of reservoir movable fluid, it can be known that the average of movable fluid saturation of extra-low permeability reservoirs and ultra-low permeability reservoirs in Changqing is more than 40%. Even though the total movable fluid saturation in ultra-low permeability (K>0.3x10-3μm2) sample is close to that in extra-low permeability one, the movable fluid content controlled by large throats in ultra-low permeability (K>0.3x10-3μm2) sandstone sample is far less than that in extra-low permeability one. The movable fluid saturation of tight reservoirs is less than that of extra-low permeability or ultra-low permeability reservoirs and the movable fluid in tight reservoirs is nearly controlled by fine throats whose radius is less than 0.2μm. The average of T2 cutoff value of ultra-low permeability reservoirs in Changqing is suggested to be 15.22ms.3. From the study of reservoir monophasic fluid seepage law, it can be known that compared with extra-low permeability reservoirs in Changqing, it is harder to inject water for ultra-low permeability and tight reservoirs in Changqing. The threshold pressure gradient of ultra-low permeability reservoirs in Changqing whose permeability is less than 0.3x10-3μm2, is far higher than that of extra-low permeability reservoirs in Changqing and lower than that of tight reservoirs in Changqing. Permeability, valid throat radius and movable fluid saturation all affect threshold pressure gradient.更多还原