Simultaneous oil recovery and residual gas storage: A pore-level analysis using in situ X-ray micro-tomography
Simultaneous oil recovery and residual gas storage: A pore-level analysis using in situ X-ray micro-tomography
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DOI：
10.1016/j.fuel.2012.06.094
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发表时间：
2013-01-01
期刊：
影响因子：
7.4
通讯作者：
Blunt, M. J.
中科院分区：
文献类型：
--
作者：
Iglauer, S.;Paluszny, A.;Blunt, M. J.
我们用标称分辨率为9微米的同步辐射对剩余气饱和度(S-GR)砂岩岩心进行了成像。我们研究了两种三相驱序列：(1)向含油和初始水的岩心注气，然后进行水驱(GW过程)；(2)向注水岩心注入气体，然后进行另一次注水(WGW过程)。在GW水淹中，我们测得S-GR显著较高(=20.6%；WGW水淹中S-GR为5.3%)，剩余油饱和度显著降低(S-或；S-或在GW水淹中为21.6%，S-或在WGW水淹中为29.3%)。我们还研究了单个捕获团簇在孔隙空间中的尺寸分布。结果表明，GW驱剩余油团簇的指数分布N与S(Tau)成正比，指数T=2.02-2.03，气团簇的指数T=2.04。在WGW过程中对气团的估计的tau(=2.32)有很大的不同。此外，我们还计算了团簇的表面积A-体积V关系。再次观察到近似的幂定律关系，A无穷大的V-p，p近似为0.75。此外，在GW洪水序列中，我们发现了夹在气相和水相之间的油层；我们在WGW洪水中没有发现这样的油层。这些结果对石油开采、碳地理封存和污染物传输有几个重要的启示：(A)使用GW驱油可以生产更多的石油和储存更多的天然气；(B)三相流中剩余油或气团的团簇尺寸分布与模拟两相流中观察到的相似；(C)有大的团簇表面积可用于将残余相溶解到水相中；然而，这个表面积比渗流理论预测的要小得多(p接近于1)，这意味着二氧化碳溶解捕获和危险有机溶剂对含水层的污染比预期的要慢，因为界面接触面积减少了。(C)2012爱思唯尔有限公司。保留所有权利。
We imaged sandstone cores at residual gas saturation (S-gr) with synchrotron radiation at a nominal resolution of (9 mu m)(3). We studied two three-phase flooding sequences: (1) gas injection into a core containing oil and initial water followed by a waterflood (gw process); (2) gas injection into a waterflooded core followed by another waterflood (wgw process). In the gw flood we measured a significantly higher S-gr (=20.6%; S-gr in the wgw flood was 5.3%) and a significantly lower residual oil saturation (S-or; S-or in the gw flood was 21.6% and S-or in the wgw flood was 29.3%). We also studied the size distribution of individual trapped clusters in the pore space. We found an approximately power-law distribution N proportional to s (tau) with an exponent tau = 2.02-2.03 for the residual oil clusters and tau = 2.04 for the gas clusters in the gw flood. tau (=2.32) estimated for the gas clusters in the wgw process was significantly different. Furthermore, we calculated the surface area A-volume V relationships for the clusters. Again an approximate power-law relationship was observed, A infinity V-p with p approximate to 0.75. Moreover, in the gw flood sequence we identified oil layers sandwiched between the gas and water phases; we did not identify such oil layers in the wgw flood. These results have several important implications for oil recovery, carbon geo-sequestration and contaminant transport: (a) significantly more oil can be produced and much more gas can be stored using a gw flood; (b) cluster size distributions for residual oil or gas clusters in three-phase flow are similar to those observed in analogue two-phase flow; (c) there is a large cluster surface area available for dissolution of the residual phase into an aqueous phase; however, this surface area is significantly smaller than predicted by percolation theory (p approximate to 1), which implies that CO2 dissolution trapping and contamination of aquifers by hazardous organic solvents is slower than expected because of reduced interfacial contact areas. (C) 2012 Elsevier Ltd. All rights reserved.