Investigation of pore-type heterogeneity and its control on microscopic remaining oil distribution in deeply buried marine clastic reservoirs
Investigation of pore-type heterogeneity and its control on microscopic remaining oil distribution in deeply buried marine clastic reservoirs
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深埋海相碎屑岩储层孔隙类型非均质性及其对微观剩余油分布的控制
DOI：
10.1016/j.marpetgeo.2020.104750
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发表时间：
2021
影响因子：
4.2
通讯作者：
Linfeng Tian
中科院分区：
文献类型：
--
作者：
Panke Sun;Huaimin Xu;Hanqing Zhu;Langbo Jia;Xiaoni Hu;Huijing Fang;Hanqiao Jiang;Zhaohui Xu;Tongwen Jiang;Xu Jiang;Linfeng Tian
孔隙类型非均质性是控制碎屑岩储层微观剩余油分布的关键因素。因此，在微观尺度上定量研究储层孔隙非均质性特征，认识其形成机理，分析其对剩余油的影响具有重要意义。针对这一问题，提出了一种以常规速度数据为输入、孔隙纵横比（α）为中间参数的流动层指示剂（FZI）表征方法，对FZI识别出的不同孔隙类型的储层样品在不同注水程度下进行CT扫描成像。结果表明，该方法可以有效地识别孔隙类型的变化，并表征速度和渗透率的变化。FZI>2.1是岩屑石英砂岩的特征，残留大量原生粒间孔，主要发育在滨岸环境。粘土边缘胶结在这种储层类型中占主导地位，因为它可以经受压实，抑制石英过度生长，从而保留具有大孔喉半径和良好连通性的粒间孔隙。该类油藏水驱时排驱压力低，水波及面积大，大部分簇状流被驱替，剩余油呈小斑块状多孔隙流形式。FZI<1.5的样品代表岩屑砂岩，粒内溶孔较多，主要发育在前滨和滨外过渡带相。该类储层经历了强烈的压实和溶蚀作用，孔喉半径小，连通性差，排替压力高。该油藏类型在驱油过程中，注入水沿着流阻较小的优先通道流动，水波及面积有限，剩余油呈簇状流动的连续特征。在上部两种储层类型之间存在1.5 < FZI<2.1的过渡带;该过渡带包含混合岩性和孔隙类型，并显示中等孔喉半径、连通性和排替压力。该类油藏剩余油以丛状流和少量多孔流的形式存在，表现为连续或小斑块的特征。此外，水驱替过程主要发生在相对较大的孔喉中，这些孔喉对每种储层类型的渗透率做出了主要贡献。这些孔喉的非均质性，如分形维数所示，控制了最终的驱油效率。该研究成果可广泛应用于类似碎屑岩储层的表征和多尺度非均质性的深入研究。
Pore-type heterogeneity is a key factor controlling the distribution of microscopic remaining oil in clastic reservoirs. It is important to quantify the characteristics of pore-type heterogeneity, understand its formation mechanisms, and analyze its impact on remaining oil at microscopic scale. Here we addressed these issues by adopting a new characterization method of flow zone indicator (FZI) with conventional velocity data as input and pore aspect ratio (α) as intermediate parameter, and conducting CT scan imaging on reservoir samples with different pore types, as identified by FZI, at different levels of water injection. The results demonstrate that this method can effectively discern pore-type changes and characterize the variabilities of velocity and permeability. A value of FZI>2.1 is characteristic of lithic quartzarenite with large amount of residual primary intergranular pores, which developed mainly in a shoreface environment. Clay rim cementation prevails in this reservoir type, as it can survive compaction, inhibit quartz overgrowth, and thus preserve intergranular pores with large pore-throat radius and good connectivity. The displacement pressure of this reservoir type is low during water flooding and the water swept area is wide; as a result, the majority of clustered flows are displaced and the remaining oil is present small patches in the form of multiporous flow. Samples with FZI<1.5 represent litharenite with large amount of intragranular dissolved pores, which developed mainly in foreshore and offshore-transition zone facies. This reservoir type underwent intense compaction and dissolution, which resulted in small pore-throat radius, poor connectivity and high displacement pressure. The injected water flows along the preferential pathways with relatively small flow resistance in this reservoir type during oil displacement such that the water swept area is limited; therefore the remaining oil is present continuous characteristics in the form of clustered flow. A transition zone with 1.5 < FZI<2.1 exists between the upper two reservoir types; this contains mixed lithologies and pore types, and exhibits medium pore-throat radius, connectivity and displacement pressure. The remaining oil in this reservoir type is present in the form of clustered flow and a small amount of multiporous flow, displaying continuous characteristics or small patches. Moreover, the water displacement process mainly occurs in relatively large pore-throats, which make a major contribution to permeability in each reservoir type. The heterogeneity of these pore-throats, as indicated by fractal dimension, controls the final oil displacement efficiency. The results of this study can be broadly applied to the characterization of similar clastic reservoirs and for further research in multi-scale heterogeneity.
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影响因子：
3.5
作者：
K. Verwer;G. Eberli;Ralf J. Weger
通讯作者：
K. Verwer;G. Eberli;Ralf J. Weger
影响因子：
3.3
作者：
H. Adesokan;Yuefeng Sun
通讯作者：
H. Adesokan;Yuefeng Sun
影响因子：
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作者：
G. Zhu;Shuichang Zhang;J. Su;Shucui Meng;Haijun Yang;Jianfeng Hu;Yongfeng Zhu
通讯作者：
G. Zhu;Shuichang Zhang;J. Su;Shucui Meng;Haijun Yang;Jianfeng Hu;Yongfeng Zhu
影响因子：
7.4
作者：
Iglauer, S.;Paluszny, A.;Blunt, M. J.
通讯作者：
Blunt, M. J.
影响因子：
7.5
作者：
H. Dakuang
通讯作者：
H. Dakuang